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Epidurals: Do They or Don’t They Increase Cesareans?

January 27th, 2015 by avatar

By Henci Goer

In October, Author Henci Goer wrote an article for Science & Sensibility, Epidural Anesthesia: To Delay or Not To Delay – That is the Question – examining the impact of the timing of an epidural on labor and birth.  Today Henci looks at some new research, Epidural analgesia in labour and risk of caesarean delivery which seeks to determine whether receiving an epidural at all impacts the likelihood of a cesarean delivery.  Lamaze International has a great infographic on epidurals that you also may find very helpful. – Sharon Muza, Community Manager, Science & Sensibility.

© J. Wasikowski, provided by Birthtastic

© J. Wasikowski, provided by Birthtastic

Let’s start with a bit of background for those of you who didn’t personally live through the early controversy over whether epidurals increased the cesarean rate. As epidurals began to achieve popularity in the late 1970s and 1980s, one researcher sounded the alarm when he and his group published a study of 714 first-time mothers showing that even after excluding women with big babies and women whose labor pattern was abnormal prior to having an epidural, epidurals remained a potent factor in cesarean rates for delayed progress (Thorp 1989). Everyone pooh-poohed his finding on grounds that observational studies can’t truly determine whether epidurals lead to more cesareans or women experiencing more prolonged, painful labors, and therefore at higher risk for cesarean, were more likely to want epidurals. The “chicken versus egg” question, they argued, couldn’t be resolved without a randomized controlled trial (RCT), and it wasn’t likely that women would agree to be assigned by chance to have an epidural or not. In point of fact, that same year saw publication of a small Danish RCT (107 women, 104 of them first-time mothers) (Philipsen 1989). It reported that having an epidural nearly tripled the cesarean rate (16% vs. 6%) for “cephalopelvic disproportion” despite no clinical evidence of CPD being a requirement for inclusion. The investigators ignored this, however, concluding only that instrumental vaginal delivery rates were similar, and epidurals provided better pain relief. In any case, the anesthetic dose was much higher than was already becoming the norm, so it could be reasonably argued that the trial’s findings wouldn’t apply to modern-day practice.

Thorp, meanwhile, took up the RCT challenge. He and his colleagues carried out an epidural versus no epidural trial in 93 first-time mothers and found that epidurals did, in fact, lead to cesareans (25% vs. 2%), not vice versa (Thorp 1993). That bit of unwelcome news precipitated a stampede to perform more RCTs, and when enough of those had accumulated, to a series of systematic reviews pooling their data (meta-analysis), of which the Cochrane review, Anim-Somuah et al. (2011), is the latest. These reached the more comfortable conclusion that epidurals didn’t increase likelihood of cesarean, and pro-epiduralists breathed a collective sigh of relief and went back, if they had ever stopped, to unreservedly recommending epidurals. (This rather sweeps under the rug the other problems epidurals can cause, but that’s a topic for another day.)

Weaknesses of the “Epidural” vs. “No Epidural” Trials

Epidural

By User:Ravedave (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html)

The finding that epidurals don’t increase cesareans is puzzling because they increase likelihood of factors associated with them (Anim-Somuah 2011). For one thing, they increase use of oxytocin to augment labor, which implies they slow labor. For another, more women run fevers, and it stands to reason that a woman progressing slowly who starts running a fever is a likely candidate for cesarean. For a third, the difference in fetal malposition (occiput posterior) rates at delivery comes close to achieving statistical significance, meaning the difference is unlikely to be due to chance. Persistent OP is strongly associated with cesarean delivery (Cheng 2006; Fitzpatrick 2001; Phipps 2014; Ponkey 2003; Senecal 2005; Sizer 2000). Epidurals even increase cesareans for fetal distress by 40%, although the absolute difference didn’t amount to much (1 more per 100 women). Could a difference exist and meta-analysis of RCTs fail to detect it?

A string of well-conducted observational studies over the years have suggested that they could (Eriksen 2011; Kjaergaard 2008; Lieberman 1996; Nguyen 2010), the most recent of which is a very large, very convincing study published last fall (Bannister-Tyrrell 2014). Its authors point out, as have others before them, the weaknesses of the RCTs, weaknesses serious enough to nullify their results or make them inapplicable to typical community practice (external validity).

To begin with, in most trials, substantial percentages of women allocated to the non-epidural group ended up having epidurals, and some women allocated to the epidural group ended up not having one. Since RCTs analyze results according to group assignment (to do otherwise would negate the point of random assignment, which is to avoid bias), not what actually happened, this diminishes differences between groups. In addition, trials were mostly confined to women with no medical or obstetric complications who were treated according to strict protocols for labor management and indications for cesarean delivery. Neither is the case in most hospitals. To these I would add that many trials lumped together first-time mothers and women with prior births when reporting outcomes. First-time mothers are much more susceptible to factors that impede progress, so including women with prior vaginal births can make it appear that epidurals are less problematic for first-time mothers than they really are. In addition, three of the trials were carried out in a hospital where participants were mostly attended by midwives, and cesarean rates were much lower than is common for women attended by obstetricians.

All of this means that any null results in meta-analyses of the trials can be taken with a grain of salt, any findings of significant differences probably represent a minimal value, and first-time moms may be harder hit than appears. To cite one example, Anim-Somuah (2011) reported that 5 more women per 100 having epidurals had a malpositioned baby at delivery (18% vs. 13%) in the 4 trials reporting this outcome, a difference, as I said, that just missed achieving statistical significance. But when I confined results to the two trials in first-time mothers alone in which 10% or fewer of the women in the “no-epidural” group had an epidural, the gap widened to 9 more per 100 (11% vs. 2%).

Summary of the Bannister-Tyrrell (2014) Analysis

Bannister-Tyrrell and colleagues (2014) drew their population from a database of 210,700 Australian women with no prior cesareans who were laboring at term with a singleton, head-down baby. A strength of the database was that, unlike most, it distinguished epidurals for labor from epidurals for delivery. Using a long list of factors, investigators constructed a propensity score for how likely a woman was to have an epidural, matched women according to their score, and compared results according to whether women with the same score had or didn’t have an epidural. Matched controls were found for 52,600 women who had an epidural and were found across the full range of propensity scores. Women having epidurals were 2.5 times more likely to have a cesarean (20% vs. 8%), or put another way, 12 more women per 100 having epidurals had a cesarean (absolute excess), which amounts to 1 additional cesarean for every 8.5 women having an epidural (number needed to harm). Among first-time mothers, women having epidurals were 2.4 times more likely to have a cesarean. Study authors didn’t provide cesarean rates for this subgroup, but the raw cesarean rates overall were 18% in first-time mothers versus 2% in women with prior births, so the effect on this more vulnerable population could be dire.

But there’s still more. Investigators further adjusted for confounding factors not captured in their database. These included differences in health-care settings (same state but not same city), care provider (women without epidurals are more likely to be attended by midwives), and for confounding interventions more likely with epidurals (continuous fetal monitoring). Relative risk of cesarean with an epidural remained at 2.5. Investigators then adjusted for the association between occiput posterior baby and cesarean by setting estimates of the risk ratio to exceed the strongest associations reported in the literature, and they assumed that the prevalence of severe labor pain was 3 to 4 times higher in women having epidurals. Factoring these into their statistical analysis reduced the risk ratio, but women having epidurals still were 50% more likely to have a cesarean. This means that with a baseline cesarean rate of 8% in women without an epidural, 12% of women with an epidural will have one or 4 more women per 100 or 1 more cesarean for every 25 women.

The Take-Home

At the very least we cannot assure women with confidence that epidurals don’t increase the likelihood of cesarean. For this reason and because of their numerous other drawbacks and considering that comfort measures and other strategies have been shown to be both effective for most women and free of adverse effects (Declercq 2006; Jones 2012), women may want to make epidurals Plan B rather than Plan A. That being said, whatever their choice, women can minimize their chance of cesarean—with or without an epidural—by choosing a midwife or doctor whose policies and practices promote spontaneous vaginal birth http://www.lamaze.org/HealthyBirthPractices.

References

Anim-Somuah, M., Smyth, R. M., & Jones, L. (2011). Epidural versus non-epidural or no analgesia in labour. Cochrane Database Syst Rev(12), CD000331. doi: 10.1002/14651858.CD000331.pub3 http://www.ncbi.nlm.nih.gov/pubmed/22161362

Bannister-Tyrrell, M., Ford, J. B., Morris, J. M., & Roberts, C. L. (2014). Epidural analgesia in labour and risk of caesarean delivery. Paediatr Perinat Epidemiol, 28(5), 400-411. http://www.ncbi.nlm.nih.gov/pubmed/25040829

Cheng, Y. W., Shaffer, B. L., & Caughey, A. B. (2006). Associated factors and outcomes of persistent occiput posterior position: A retrospective cohort study from 1976 to 2001. J Matern Fetal Neonatal Med, 19(9), 563-568. http://www.ncbi.nlm.nih.gov/pubmed/16966125?dopt=Citation

Declercq, E., Sakala, C., Corry, M. P., & Applebaum, S. (2006). Listening to Mothers II: Report of the Second National U.S. Survey of Women’s Childbearing Experiences. New York: Childbirth Connection. http://childbirthconnection.org/pdfs/LTMII_report.pdf

Eriksen, L. M., Nohr, E. A., & Kjaergaard, H. (2011). Mode of delivery after epidural analgesia in a cohort of low-risk nulliparas. Birth, 38(4), 317-326. http://www.ncbi.nlm.nih.gov/pubmed/22112332

Fitzpatrick, M., McQuillan, K., & O’Herlihy, C. (2001). Influence of persistent occiput posterior position on delivery outcome. Obstet Gynecol, 98(6), 1027-1031. http://www.ncbi.nlm.nih.gov/pubmed/11755548?dopt=Citation

Jones, L., Othman, M., Dowswell, T., Alfirevic, Z., Gates, S., Newburn, M., . . . Neilson, J. P. (2012). Pain management for women in labour: an overview of systematic reviews. Cochrane Database Syst Rev, 3, CD009234. http://www.ncbi.nlm.nih.gov/pubmed/22419342

Kjaergaard, H., Olsen, J., Ottesen, B., Nyberg, P., & Dykes, A. K. (2008). Obstetric risk indicators for labour dystocia in nulliparous women: a multi-centre cohort study. BMC Pregnancy Childbirth, 8, 45. http://www.ncbi.nlm.nih.gov/pubmed/18837972?dopt=Citation

Lieberman, E., Lang, J. M., Cohen, A., D’Agostino, R., Jr., Datta, S., & Frigoletto, F. D., Jr. (1996). Association of epidural analgesia with cesarean delivery in nulliparas. Obstet Gynecol, 88(6), 993-1000. http://www.ncbi.nlm.nih.gov/pubmed/8942841

Nguyen, U. S., Rothman, K. J., Demissie, S., Jackson, D. J., Lang, J. M., & Ecker, J. L. (2010). Epidural analgesia and risks of cesarean and operative vaginal deliveries in nulliparous and multiparous women. Matern Child Health J, 14(5), 705-712. http://www.ncbi.nlm.nih.gov/pubmed/19760498?dopt=Citation

Philipsen, T., & Jensen, N. H. (1989). Epidural block or parenteral pethidine as analgesic in labour; a randomized study concerning progress in labour and instrumental deliveries. Eur J Obstet Gynecol Reprod Biol, 30(1), 27-33. http://www.ncbi.nlm.nih.gov/pubmed/2924990

Phipps, H., Hyett, J. A., Graham, K., Carseldine, W. J., Tooher, J., & de Vries, B. (2014). Is there an association between sonographically determined occipito-transverse position in the second stage of labor and operative delivery? Acta Obstet Gynecol Scand, 93(10), 1018-1024. http://www.ncbi.nlm.nih.gov/pubmed/25060716

Ponkey, S. E., Cohen, A. P., Heffner, L. J., & Lieberman, E. (2003). Persistent fetal occiput posterior position: obstetric outcomes. Obstet Gynecol, 101(5 Pt 1), 915-920. http://www.ncbi.nlm.nih.gov/pubmed/12738150?dopt=Citation

Senecal, J., Xiong, X., Fraser, W. D., & Pushing Early Or Pushing Late with Epidural study, group. (2005). Effect of fetal position on second-stage duration and labor outcome. Obstet Gynecol, 105(4), 763-772. http://www.ncbi.nlm.nih.gov/pubmed/15802403

Sizer, A. R., & Nirmal, D. M. (2000). Occipitoposterior position: associated factors and obstetric outcome in nulliparas. Obstet Gynecol, 96(5 Pt 1), 749-752. http://www.ncbi.nlm.nih.gov/pubmed/11042312?dopt=Citation

Thorp, J. A., Hu, D. H., Albin, R. M., McNitt, J., Meyer, B. A., Cohen, G. R., & Yeast, J. D. (1993). The effect of intrapartum epidural analgesia on nulliparous labor: a randomized, controlled, prospective trial. Am J Obstet Gynecol, 169(4), 851-858. http://www.ncbi.nlm.nih.gov/pubmed/8238138?dopt=Citation

Thorp, J. A., Parisi, V. M., Boylan, P. C., & Johnston, D. A. (1989). The effect of continuous epidural analgesia on cesarean section for dystocia in nulliparous women. Am J Obstet Gynecol, 161(3), 670-675. http://www.ncbi.nlm.nih.gov/pubmed/2782350

About Henci Goer

Henci Goer

Henci Goer

Henci Goer, award-winning medical writer and internationally known speaker, is the author of The Thinking Woman’s Guide to a Better Birth and Optimal Care in Childbirth: The Case for a Physiologic Approach She is the winner of the American College of Nurse-Midwives “Best Book of the Year” award. An independent scholar, she is an acknowledged expert on evidence-based maternity care.  

 

Cesarean Birth, Childbirth Education, Epidural Analgesia, Guest Posts, Healthy Birth Practices, Medical Interventions, New Research, Pain Management, Research , , , , , , ,

Epidural Analgesia: To Delay or Not to Delay, That Is the Question

October 23rd, 2014 by avatar

By Henci Goer

Unless you have been “off the grid” on a solitary trek, surely you have read and heard the recent flurry of discussion surrounding the just released study making the claim that the timing of when a woman receives an epidural (“early” or “late” in labor) made no difference in the rate of cesarean delivery.  Your students and clients may have been asking questions and wondering if the information is accurate.  Award winning author and occasional Science & Sensibility contributor Henci Goer reviews the 9 studies that made up the Cochrane systematic review: Early versus late initiation of epidural analgesia for labour to determine what they actually said.  Read her review here and share if you agree with all the spin in the media about this new research review. Additionally, head on over to the professional and parent Lamaze International sites to check out the new infographic on epidurals to share with your students and clients.- Sharon Muza, Science & Sensibility Manager. 

Epidural infographic oneArticles have been popping up all over the internet in recent weeks citing a new Cochrane systematic review- Early versus late initiation of epidural analgesia for labour, concluding that epidural analgesia for labor needn’t be delayed because early initiation doesn’t increase the likelihood of cesarean delivery, or, for that matter, instrumental vaginal delivery (Sng 2014). The New York Times ran this piece. Some older studies have found that early initiation appeared to increase likelihood of cesarean (Lieberman 1996; Nageotte 1997; Thorp 1991), which is plausible on theoretical grounds. Labor progress might be more vulnerable to disruption in latent than active phase. Persistent occiput posterior might be more frequent if the woman isn’t moving around, and fetal malposition greatly increases the likelihood of cesarean and instrumental delivery. Which is right? Let’s dig into the review.

The review includes 9 randomized controlled trials of “early” versus “late” initiation of epidural analgesia. Participants in all trials were limited to healthy first-time mothers at term with one head-down baby. Five trials further limited participants to women who began labor spontaneously, three mixed women being induced with women beginning labor spontaneously, and in one, all women were induced. Analgesia protocols varied, but all epidural regimens were of modern, low-dose epidurals. So far, so good.

Examining the individual trials, though, we see a major problem. You would think that the reviewers would have rejected trials that failed to divide participants into distinct groups, one having epidural initiation in early labor and the other in more advanced labor, since the point of the review is to determine whether early or late initiation makes a difference. You would think wrong. Of the nine included trials, six failed to do this.

cc photo bryanrmason http://flickr.com/photos/b-may/397189835

cc photo bryanrmason http://flickr.com/photos/b-may/397189835

The two Chestnut trials (1994a; 1994b) had the same design, differing only in that one was of women who were laboring spontaneously at trial entry and the other included women receiving oxytocin for induction or augmentation. Women were admitted to the trial if they were dilated between 3 and 5 cm. Women in the early group got their epidural immediately while women in the late group could have an epidural only if they were dilated to 5 cm or more. If late-group women were not dilated to 5 cm, they were given systemic opioids and could have a second dose of opioid one hour later. They could have an epidural when they attained 5 cm dilation or regardless of dilation, an hour after the second opioid dose. Let’s see how that worked out.

Among the 149 women in the trial that included women receiving oxytocin (Chestnut 1994b), median dilation in the early group at time of epidural initiation was 3.5 cm, meaning that half the women were dilated more and half less than this amount. The interquartile deviation was 0.5 cm, which means that values were fairly tightly clustered around the median. The authors state, however, that cervical dilation was assessed using 0.5 increments which meant that dilation of 3-4 cm was recorded as 3.5. In other words, women in the early group might have been dilated to as much as 4 cm. The median dilation in the late group was 5.0 cm, again with a 0.5 cm interquartile deviation. Some women in the late group, therefore, were not yet dilated to 5 cm when their epidural began, and, in fact, the authors report that 26 of the 75 women (35%) in the late group were given their epidural after the second dose of opioid but before attaining 5 cm dilation. The small interquartile deviation in the late group tells us that few, if any, women would have been dilated much more than 5 cm. Add in that assessing dilation isn’t exact, so women might have been a bit more or less dilated than they were thought to be, and it becomes clear that the “early” and “late” groups must have overlapped considerably. Furthermore, pretty much all of them were dilated between 3 and 5 cm when they got their epidurals, which means that few of these first-time mothers would have been in active labor, as defined by the new ACOG standards.

Overlap between early and late groups must have been even greater in Chestnut et al.’s (1994a) trial of 334 women laboring spontaneously at trial entry because median dilation in the early group was greater than in the other trial (4 cm, rather than 3.5) while median dilation in the late group was the same (5.0 cm), and interquartile deviation was even tighter in the late group (0.25 cm, rather than 0.5 cm). As before, dilation was measured in 0.5 cm increments, which presumably means that women in the early group dilated to 4-5 cm would have been recorded as “4.5,” thereby qualifying them for the “early” group even though they might have been as much as 5 cm dilated.

Based on my analysis, I would argue that there was no clinically meaningful difference in dilation between early and late groups in either trial.

A second pair of trials, one a mixed trial of spontaneous labor onset and induction and the other all induced, also had the same design in both trials (Wong 2005; Wong 2009). All women were less than 4 cm dilated at first request for pain medication. In the early group, women had an opioid injected intrathecally, i.e. the “spinal” part of a combined spinal-epidural, and an epidural catheter was set. At the second request, an epidural was initiated. In the late group, women were given a systemic opioid. At second request, they were given a second dose of systemic opioid if they hadn’t reached 4 cm dilation and an epidural if they had dilated to 4 cm or more. At third request, they were given an epidural regardless of dilation. Women who had no vaginal exam at second request and were given an epidural were “assumed,” in the authors’ words, to be dilated to at least 4 cm. What were the results?

Wong (2005) included 728 women, some beginning labor spontaneously and some induced. You may already have noticed the flaw in the trials’ design: Wong and colleagues confused the issue by considering intrathecal opioid to be equivalent to epidural anesthetic in the early group, although women didn’t actually receive anesthetic until their second request for pain medication some unknown time later. So far as I know we have no evidence that opiods, spinal or epidural, have any effect on labor progress. As to dilation at the time of epidural initiation, 63% of women in the so-called “early” group were either determined or assumed to be at 4 cm dilation or more while in the late group, some unknown proportion were less than 4 cm dilated either because they got their epidural at third pain medication request regardless of dilation or they were assumed to be at 4 or more cm dilation at second request, but weren’t assessed.

Wong (2009), a study of 806 induced women, was set up the same way but reported data somewhat differently. Early-group women were administered a spinal opioid at a median of 2 cm dilation and an interquartile range of 1.5 to 3 cm, which means that values in the middle 50% of the dataset ranged from 1.5 to 3 cm. We have no information on dilation at the time they received their epidural. The median dilation at which late-group women had their epidural initiated was 4 cm with an interquartile range of 3 to 4 cm, that is, in the middle 50% of the dataset ranged from 3 to 4 cm dilation.

As with the Chestnut trials, dilation at time of epidural initiation in the two Wong trials must have overlapped considerably between groups. And, again, few women in the late epidural group would have been in active labor. The Wong trials, however, muddy the waters even further by considering spinal opioid to be the same thing as epidural anesthetic, and while the authors were careful to use the term “neuraxial analgesia,” the Cochrane reviewers made no such distinction.

This brings us to Parameswara (2012), a trial of 120 women that included both spontaneous onset and induced labors. This trial defined the early group as women less than 2 cm dilated at time of epidural initiation and the late group as women more than 2 cm dilated. That’s all the information they provide on group allocation.

Last of the six, we have Wang (2011), a trial of 60 women in spontaneous labor. All women were given intrathecal anesthetic plus opioid. The early group was started on epidural anesthetic plus opioid 20 minutes later whereas the late group had their epidural initiated when they requested additional pain relief. No information is given on dilation at time of epidural initiation. Not only do we have no idea whether early and late groups differed from one another, women in both groups received neuraxial anesthetic at the same time.

In summary, “garbage in, garbage out.” No conclusions can be drawn about the effect of early versus late epidural administration from these six studies.

The other three studies are a different story. They achieve a reasonable separation between groups. Luxman (1998) studied 60 women with spontaneous labor onset. The early group had a mean, i.e., average, dilation of 2.3 cm with a standard deviation of + or – 0.6 cm while the late group had a mean dilation of 4.5 cm + or – 0.2 cm. Ohel (2006) studied a mixed spontaneous onset and induced group of 449 women. The mean dilation at initiation in the early group was 2.4 cm with a standard deviation of 0.7 cm, and the late group had a mean dilation of 4.6 cm with a standard deviation of 1.1 cm. Wang (2009), the behemoth of the trials, included 12,629 women who began labor spontaneously. The early epidural group had a median dilation of 1.6 cm with an interquartile range of 1.1 to 2.8 and the late group a median of 5.1 cm dilation with an interquartile range of 4.2 to 5.7. Cesarean and instrumental delivery rates were similar between early and late groups in all three trials, so had reviewers included only these three trials, they would still have arrived at the same conclusion: early epidural initiation doesn’t increase likelihood of cesarean and instrumental delivery.

We’re not done, though. Wang (2009) points us to a second, even bigger issue.

The Wang (2009) trial, as did all of the trials, limited participants to healthy first-time mothers with no factors that would predispose them to need a cesarean. The Wang trial further excluded women who didn’t begin labor spontaneously. Nevertheless, the cesarean rate in these ultra-low-risk women was an astonishing 23%. Comparing the trials side-by-side reveals wildly varying cesarean and instrumental vaginal delivery rates in what are essentially homogeneous populations.

© Henci Goer

© Henci Goer

© Henci Goer

© Henci Goer

Comparing the trials uncovers that epidural timing doesn’t matter because any effect will be swamped by the much stronger effect of practice variation.

Analysis of the trials teaches us two lessons: First, systematic reviews can’t always be taken at face value because results depend on the beliefs and biases that the reviewers bring to the table. In this case, they blinded reviewers from seeing that two-thirds of the trials they included weren’t measuring two groups of women, one in early- and one in active-phase labor. Second, practice variation can be an unacknowledged and potent confounding factor for any outcome that depends on care provider judgment.

Conclusion

So what’s our take home? Women need to know that with a judicious care provider who strives for spontaneous vaginal birth whenever possible, early epidural administration won’t increase odds of cesarean or instrumental delivery. With an injudicious one, late initiation won’t decrease them. That being said, there are other reasons to delay an epidural. Maternal fever is associated with epidural duration. Running a fever in a slowly progressing labor could tip the balance toward cesarean delivery as well as have consequences for the baby such as keeping the baby in the nursery for observation, testing for infection, or administering prophylactic IV antibiotics. Then too, a woman just might find she can do very well without one. Epidurals can have adverse effects, some of them serious. Comfort measures, cognitive strategies, and all around good emotionally and physically supportive care don’t. Hospitals, therefore, should make available and encourage use of a wide range of non-pharmacologic alternatives and refrain from routine practices that increase discomfort and hinder women from making use of them. Only then can women truly make a free choice about whether and when to have an epidural.

After reading Henci’s review and the study, what information do you feel is important for women to be aware of regarding epidural use in labor?  What will you say when asked about the study and timing of an epidural?  You may want to reference a previous Science & Sensibility article by Andrea Lythgoe, LCCE, on the use of the peanut ball to promote labor progress when a woman has an epidural. – SM 

References

Caughey, A. B., Cahill, A. G., Guise, J. M., & Rouse, D. J. (2014). Safe prevention of the primary cesarean delivery. American journal of obstetrics and gynecology210(3), 179-193.

Chestnut, D. H., McGrath, J. M., Vincent, R. D., Jr., Penning, D. H., Choi, W. W., Bates, J. N., & McFarlane, C. (1994a). Does early administration of epidural analgesia affect obstetric outcome in nulliparous women who are in spontaneous labor? Anesthesiology, 80(6), 1201-1208. http://www.ncbi.nlm.nih.gov/pubmed/8010466?dopt=Citation

Chestnut, D. H., Vincent, R. D., Jr., McGrath, J. M., Choi, W. W., & Bates, J. N. (1994b). Does early administration of epidural analgesia affect obstetric outcome in nulliparous women who are receiving intravenous oxytocin? Anesthesiology, 80(6), 1193-1200. http://www.ncbi.nlm.nih.gov/pubmed/8010465?dopt=Citation

Lieberman, E., Lang, J. M., Cohen, A., D’Agostino, R., Jr., Datta, S., & Frigoletto, F. D., Jr. (1996). Association of epidural analgesia with cesarean delivery in nulliparas. Obstet Gynecol, 88(6), 993-1000. http://www.ncbi.nlm.nih.gov/pubmed/8942841

Luxman, D., Wolman, I., Groutz, A., Cohen, J. R., Lottan, M., Pauzner, D., & David, M. P. (1998). The effect of early epidural block administration on the progression and outcome of labor. Int J Obstet Anesth, 7(3), 161-164. http://www.ncbi.nlm.nih.gov/pubmed/15321209?dopt=Citation

Nageotte, M. P., Larson, D., Rumney, P. J., Sidhu, M., & Hollenbach, K. (1997). Epidural analgesia compared with combined spinal-epidural analgesia during labor in nulliparous women. N Engl J Med, 337(24), 1715-1719. http://www.ncbi.nlm.nih.gov/pubmed/9392696?dopt=Citation

Ohel, G., Gonen, R., Vaida, S., Barak, S., & Gaitini, L. (2006). Early versus late initiation of epidural analgesia in labor: does it increase the risk of cesarean section? A randomized trial. Am J Obstet Gynecol, 194(3), 600-605. http://www.ncbi.nlm.nih.gov/pubmed/16522386?dopt=Citation

Parameswara, G., Kshama, K., Murthy, H. K., Jalaja, K., Venkat, S. (2012). Early epidural labour analgesia: Does it increase the chances of operative delivery? British Journal of Anaesthesia 108(Suppl 2):ii213–ii214. Note: This is an abstract only so all data from it come from the Cochrane review.

Sng, B. L., Leong, W. L., Zeng, Y., Siddiqui, F. J., Assam, P. N., Lim, Y., . . . Sia, A. T. (2014). Early versus late initiation of epidural analgesia for labour. Cochrane Database Syst Rev, 10, CD007238. doi: 10.1002/14651858.CD007238.pub2 http://www.ncbi.nlm.nih.gov/pubmed/25300169

Thorp, J. A., Eckert, L. O., Ang, M. S., Johnston, D. A., Peaceman, A. M., & Parisi, V. M. (1991). Epidural analgesia and cesarean section for dystocia: risk factors in nulliparas. Am J Perinatol, 8(6), 402-410. http://www.ncbi.nlm.nih.gov/pubmed/1814306?dopt=Citation

Wang, F., Shen, X., Guo, X., Peng, Y., & Gu, X. (2009). Epidural analgesia in the latent phase of labor and the risk of cesarean delivery: a five-year randomized controlled trial. Anesthesiology, 111(4), 871-880. http://www.ncbi.nlm.nih.gov/pubmed/19741492?dopt=Citation

Wang, L. Z., Chang, X. Y., Hu, X. X., Tang, B. L., & Xia, F. (2011). The effect on maternal temperature of delaying initiation of the epidural component of combined spinal-epidural analgesia for labor: a pilot study. Int J Obstet Anesth, 20(4), 312-317. http://www.ncbi.nlm.nih.gov/pubmed/21840705

Wong, C. A., McCarthy, R. J., Sullivan, J. T., Scavone, B. M., Gerber, S. E., & Yaghmour, E. A. (2009). Early compared with late neuraxial analgesia in nulliparous labor induction: a randomized controlled trial. Obstet Gynecol, 113(5), 1066-1074. http://www.ncbi.nlm.nih.gov/pubmed/19384122?dopt=Citation

Wong, C. A., Scavone, B. M., Peaceman, A. M., McCarthy, R. J., Sullivan, J. T., Diaz, N. T., . . . Grouper, S. (2005). The risk of cesarean delivery with neuraxial analgesia given early versus late in labor. N Engl J Med, 352(7), 655-665. http://www.ncbi.nlm.nih.gov/pubmed/15716559?dopt=Citation

About Henci Goer

Henci Goer

Henci Goer

Henci Goer, award-winning medical writer and internationally known speaker, is the author of The Thinking Woman’s Guide to a Better Birth and Optimal Care in Childbirth: The Case for a Physiologic Approach She is the winner of the American College of Nurse-Midwives “Best Book of the Year” award. An independent scholar, she is an acknowledged expert on evidence-based maternity care.  

Cesarean Birth, Childbirth Education, Epidural Analgesia, Guest Posts, informed Consent, Medical Interventions, New Research, Systematic Review , , , , , , ,

Cochrane Systematic Review Supports Lamaze Healthy Birth Practice #2- Walk, Move Around And Change Positions Throughout Labor

December 19th, 2013 by avatar
Image Source: © Sharon Muza

Image Source: © Sharon Muza

Today, author Henci Goer takes a look at a new Cochrane Systematic Review; “Maternal positions and mobility during first stage labour” and finds that the results of this review support the 2nd Lamaze International Healthy Birth Practice: Walk, move around and change positions throughout labor. Families taking Lamaze childbirth classes learn how they can promote physiologic birth by using a variety of positions throughout their labor, but women don’t have to take a childbirth class to know that walking and trying different positions reduces pain and speeds up labor.  Intuitively, women respond to the needs of their baby and their body during labor.  Henci examines the review and shares some of the benefits that were found in the women who followed the 2nd Healthy Birth Practice to promote safe and healthy birth. – Sharon Muza, Community Manager.

Advocates for physiologic care in labor will be pleased, although not surprised, to know that a Cochrane systematic review supports mobility and upright positioning in first-stage labor (the cervical dilation phase) (Lawrence 2013.) The review includes 18 randomized controlled trials (RCTs) comprising 3337 women not having epidurals at trial entry and 7 trials comprising 1881 women in which all participants had epidurals or combined spinal-epidurals at trial entry.

The body of data poses challenges in analysis and interpretation. Trials were published between 1963 and 2012 and conducted in 13 countries. As reviewers note, this means that they took place in highly varied cultural and healthcare contexts, equally varied expectations on the part of staff and laboring women, and with evolving healthcare technologies, all of which could influence results. In addition, comparison “treatment” and “control” groups also varied widely and overlapped among them. So, for example, one trial compared walking with remaining in bed in whatever posture, including upright postures; another compared walking with recumbent postures; and still another combined sitting and walking as upright postures and compared them with recumbent postures. That being said, here is what the reviewers found:

Compared with recumbent postures and bed care, upright postures and walking in women without epidurals at trial entry:

• Shortened first-stage labor duration by a mean difference of 1 hour 22 minutes in women overall (15 trials, 2503 women) and by 1 hour 13 minutes in first-time mothers (12 trials, 1486 women). In women with prior births (4 trials, 662 women), duration differed by only 34 minutes, and the difference just missed achieving statistical significance, that is, statistical analysis shows that the difference is unlikely to be due to chance. By comparison, rupturing membranes, commonly used to “get the show on the road,” had no effect on first-stage duration in women overall (5 trials, 1127 women) (Smyth 2013), and too few women were reported according to first-time or prior births to draw meaningful conclusions.

• Decreased likelihood of cesarean delivery (14 trials, 2682 women) by 30%. Likelihood decreased by 20% in first-time mothers (8 trials, 1237 women) and 40% in women with prior births (4 trials, 775 women), but the differences didn’t achieve statistical significance probably because aggregated numbers were too small (underpowered) and cesarean rates too low to detect a difference. By contrast, rupturing membranes increases the likelihood of cesarean surgery by 30%, a risk that misses achieving statistical significance by a whisker and probably would have achieved significance had not so many women assigned to “conserve membranes” actually had their membranes ruptured (Smyth 2013).

• Reduced use of epidural analgesia (9 trials, 2107 women) by 20%.

• Didn’t increase satisfaction or decrease complaints of pain, but only one small study (107 women) measured satisfaction, and among the three trials (338 women) evaluating pain, women reported less pain in two of them, but in the third (201 women), which comprised 60% of the population overall, participants assigned to sit or walk were not allowed to lie down at any time during first stage. Bloom et al. (1998), by far the largest of any of the trials at 1067 participants, wasn’t included in the pain and satisfaction assessments probably because they took a different approach. They asked women who walked whether they would want to walk in a future labor. Ninety-nine percent said “Yes,” which would seem a ringing endorsement of ambulation.

• Showed no evidence of increasing maternal, fetal, or neonatal harm. In fact, one small trial (200 women) reported significantly fewer admissions to neonatal intensive care.

Benefits were maintained when subgroupings of upright postures were compared with subgroupings of recumbent postures, as for example, walking compared with recumbent/supine/lateral or sitting and standing, squatting, kneeling, or walking compared with recumbent/supine/lateral.

No benefits were found for walking or upright postures (7 trials, 1881 women) in women who had epidurals or combined spinal-epidurals at trial entry. This doesn’t really mean much, though, because in some trials, substantial percentages of women assigned to walk didn’t actually do so, and in others “ambulation” was defined to be as little as 5 minutes of walking per hour.

The review leaves some questions open: Can mobility be used to treat delayed progress? Should women with ruptured membranes be allowed to walk? What about women at risk for fetal compromise? To the first question, it makes sense to encourage walking and upright positioning as a first-line measure to treat progress delay. The alternatives, rupturing membranes and oxytocin augmentation, have potential harms while walking and position changes don’t. To the second, when upright, gravity would tend to bring the presenting part downward to block the cervical opening, thereby protecting against umbilical cord prolapse. A common sense approach might be to monitor fetal heart tones throughout a contraction upon the woman first assuming an upright position and repeat whenever she returns to an upright position after lying down. To the last question, studies would need to be done, but rupturing membranes increases risk of fetal compromise by releasing the fluid that prevents umbilical cord compression (you can’t compress a liquid), and augmentation increases contraction intensity, which also could increase risk of compromise in a vulnerable fetus.

The true benefits of mobility are almost certainly much greater than the review shows. This is because RCTs are analyzed according to “intent to treat,” that is, participants are kept with their assigned group regardless of their actual treatment. To do otherwise would negate the point of random assignment, which is to avoid bias; however, when substantial percentages of participants receive the treatment of the other group, as is the case with many of the mobility RCTs, it both diminishes differences between groups and makes it harder to detect a significant difference between them. This was a problem in all the mobility RCTs, not just the ones where women already had regional analgesia on board. Again, take Bloom et al. (1998): among women assigned to walk, 22%—approaching 1 in 4—never walked at all, and of the women who did, the mean time spent out of bed was an hour mostly because of policies that kept them in, or returned them to, bed.

The reviewers conclude:

[W]e believe wherever possible, women should be informed of the benefits of upright positions, encouraged and supported to take up whatever positions they choose, they should not have their freedom of movement options restricted unless clinically indicated, and they should avoid spending long periods supine (p. 23).

It isn’t enough, though, to advise women that it’s a good idea to stay mobile and stay off their backs unless staff follow through on not restricting freedom of movement. As matters currently stand, conventional hospital labor management couldn’t do a better job of restricting mobility if that were its intended goal. To turn that around, hospitals would need to:

• Provide an environment conducive to mobility, including ample space for moving around and props such as birth balls, rocking chairs, and cushions,

• Provide comfort measures such as hot and cold packs, private showers, and soaking tubs to reduce and delay use of epidural analgesia,

• Train staff in encouraging and providing physical assistance in changing positions, in the use of mobility props, and in how to provide emotionally supportive care,

• Welcome doulas who can share the burden of providing physical and emotional support,

• Use intermittent listening to fetal heart tones except when continuous monitoring is medically indicated,

• Reserve IVs for medical indications, which would mean allowing women oral intake of fluids and calories, and

• When mobility-inhibiting interventions are required or the woman desires an epidural, minimize their impact by such measures as telemetry monitoring, inserting IV catheters in the forearm rather than the hand or wrist or using saline locks instead of IVs, and encouraging women with epidurals to assume upright positions and change positions periodically.

In other words, promoting mobility in labor is the proverbial tip of the iceberg. Floating below is the vast bulk of providing physiologic care. That won’t be easy for a number of reasons.

For one thing, medical research principles require that investigators define the intervention under evaluation precisely and maximize compliance with its administration. But this is the direct opposite of women doing what instinctively feels best in an environment that encourages their experimentation and is free from elements that inhibit or restrict them. We have no trials that compare this style of care with conventional medical-model management, which means we don’t have data showing the true degree of harm arising from confining and circumscribing mobility in labor or the magnitude of the benefits to be gained with promoting it. Without that knowledge, there is little incentive to change.

For another, in the topsy-turvy world of medical-model research, maternal movements and physiologically normal behaviors are framed as “interventions.” This means that being up and around and having the freedom to labor in the positions of the woman’s choice has to prove itself, not confinement to bed and positioning restriction. What is more, to institute change, the “intervention” must prove itself superior according to medical model concepts of improved outcomes, or conventional management stands, however much that management lacks an evidence basis. This explains how Bloom and colleagues could entitle their trial “Lack of effect of walking on labor and delivery” despite walking having no harms and 99% of women who walked wanting to do so again in a future labor.

Finally, powerful forces line up against instituting the sweeping changes that would be required to convert to mobility-friendly care. Inertia is one. People will generally resist change even when it benefits them personally, which in this case it doesn’t. Economics is another. The costs of maintaining a 24/7 obstetric analgesia service demand that most women have epidurals while any renovation expenses, such as providing private showers, soaking tubs, or telemetry monitoring, would not be reimbursed. Hospital culture is perhaps the biggest obstacle of all. “This is the way we’ve always done it” and “what is must be right” are potent impediments to improvement. Specifically, so long as reducing cesarean rates isn’t a shared, strongly-held goal—and a cursory glance at hospital cesarean rates shows that it isn’t in most hospitals—motivation to change will be low.

All of this is to say that reform won’t be easy, not that it can’t be done, and, I would add, the wellbeing of mothers and babies obliges us to try. In that interest, can we crowd source strategies? Are any hospitals in your community mobility friendly? What are their practices and policies? Have any of you been involved in projects to increase mobility in labor, and if so, what went well and what would you do differently?

References

Bloom, S. L., McIntire, D. D., Kelly, M. A., Beimer, H. L., Burpo, R. H., Garcia, M. A., & Leveno, K. J. (1998). Lack of effect of walking on labor and delivery. N Engl J Med, 339(2), 76-79. http://www.ncbi.nlm.nih.gov/pubmed/9654537?dopt=Citation

Lawrence, A., Lewis, L., Hofmeyr, G. J., & Styles, C. (2013). Maternal positions and mobility during first stage labour. Cochrane Database Syst Rev, 10, CD003934. doi: 10.1002/14651858.CD003934.pub4 http://www.ncbi.nlm.nih.gov/pubmed/24105444

Smyth, R. M., Markham, C., & Dowswell, T. (2013). Amniotomy for shortening spontaneous labour. Cochrane Database Syst Rev, 6, CD006167. doi: 10.1002/14651858.CD006167.pub4 http://www.ncbi.nlm.nih.gov/pubmed/23780653

 

Evidence Based Medicine, Guest Posts, Healthy Birth Practices, Healthy Care Practices, New Research, Push for Your Baby, Research , , , , , ,

Safe at Home? New Home Vs. Hospital Birth Study Reviewed by Henci Goer

November 26th, 2013 by avatar

 Regular contributor Henci Goer examines the most recent study on the safety of home birth in the United States.  When taking a closer look at the data analysis done by the authors, there are concerns not addressed in the study, that raise issues that cause the study’s conclusions to be questioned. Henci shares some other studies that do not reach the same results about the safety of home birth. Have you read this study?  If you had read this study too, did you find more questions than answers when you were done? – Sharon Muza, Community Manager, Science & Sensibility.

“Researchers have already cast much darkness on the subject, and if they continue their investigation, we shall soon know nothing at all.” – Mark Twain

flickr.com/photos/vestfamily/2591899412/

The latest contender in the long list of studies attempting to compare the safety of home and hospital birth, “Selected perinatal outcomes associated with planned home births in the United States,” was published last month (Cheng 2013). Let’s start by summarizing the study:

Using data compiled from the U.S. birth certificate, Cheng and colleagues compared outcomes between 12,039 women “planning” home births with 2,081,753 women having hospital births. All women were at term (between 37 and 43 weeks) and carrying one head-down baby. Women with prior cesarean were not excluded. After adjustment for numerous factors including number of prior births, medical conditions (hypertension, diabetes), risk factors (smoking), and social and demographic factors (race/ethnicity, age, marital status), women having home births were much less likely to have an instrumental vaginal delivery (0.1% vs. 6.2%; odds ratio 0.1), induced labor (1.4% vs. 25.7%; odds ratio 0.2), or labor augmentation (2.1% vs. 22.2%; odds ratio 0.3). They were also, however, twice as likely to have a baby with a 5-minute Apgar less than 4 (0.24% vs. 0.37%; odds ratio 1.9), three times as likely to have a baby experience neonatal seizure (0.06% vs. 0.02%; odds ratio 3.1), and more than twice as likely to have a baby with 5-minute Apgar less than 7 (2.42% vs. 1.17%; odds ratio 2.4). On the other hand, similar percentages of babies needed more than 6 hours of ventilator support, and babies born at home were much less likely to be admitted to intensive care (0.57% vs. 3.03%; odds ratio 0.2). In the discussion, the investigators note that removing the 489 women with previous cesareans who had planned home birth and women with medical or obstetric conditions did not alter that infants of women with prior births who planned home birth were more likely to have a low Apgar score. They don’t specify whether this was 5-minute Apgar less than 4 or less than 7 nor do they report the occurrence rate in this higher-risk subgroup.

There is more. To evaluate the effect of birth attendant qualifications, the investigators excluded births attended by doctors or unknown birth attendant and stratified the remaining home birth population into those attended by professional midwives and those attended by “other midwives.” (Confusingly, study authors state that Certified Professional Midwives [CPMs] were categorized as Certified Nurse-Midwives in the birth certificate data yet go on to refer solely to “CNMs” in the rest of the analysis.) In the subset attended by professional midwives, newborn outcomes were similar except that hospital-born infants were more likely to be admitted to intensive care (0.37% vs. 3.03%; odds ratio 0.1).

Cheng and colleagues conclude that while women planning home births are less likely to experience obstetric intervention, their babies are more likely to be born in poor condition. Do their data warrant that conclusion?

To begin with, the relevant question isn’t the tradeoffs between planned home birth per se and hospital birth. It is: “What are the excess risks for healthy women at low risk of urgent complications who plan home birth with qualified home birth attendants compared with similar women planning hospital birth?” This study can’t answer that question. Here’s why:

The study only includes women actually delivering at home, but you can’t make a meaningful comparison unless you have the outcomes of women transferred to hospital. “Planning” in this study meant only that birth at home wasn’t accidental, not the more usual meaning that birth may be planned at home but problems during labor may alter that plan. I discovered this when I wrote the lead author to request cesarean rates, which, oddly, to me, were not reported in the study. She responded that this was because cesareans aren’t performed at home. Puzzled by this explanation, I wrote back that neither are instrumental vaginal delivery, induction, nor labor augmentation, which were reported. She responded that birth certificate data don’t state how labor was induced or augmented but that perhaps at home births it was by rupturing membranes and that “apparently some midwives or birth attendants do perform vacuum extraction at home,” but it is rare since only 10 were reported.

Not all women planning home birth were low-risk. For one thing, women with prior cesareans were included. For another, the methods section states that the analysis adjusted for medical risk, and the discussion notes that women with prior children in the home birth group were more likely to have babies with low Apgar scores even after removing women with medical risk, which implies that some of them had medical problems.

Not all women in the home birth group had qualified home birth attendants. Outcome data on the overall population came from women recorded as being attended by MDs, DOs, “other midwife,” “others,” and “unknown/not stated” as well as by professional midwives.

Rates of neonatal seizure and 5-minute Apgar less than 4 were very low, and the study doesn’t report on perinatal death or permanent disability. As concerning as an excess in low Apgar scores and seizures may be, the real question is excess incidence of permanent harm. Even without limiting the population to low-risk women with qualified care providers, only 1 more baby per 1000 born at home experienced very low 5-minute Apgar, and only 4 more babies per 10,000 experienced neonatal seizure, and while babies born in poor condition are more likely to incur permanent neurologic damage or die, most will recover. Also, as we saw, differences in rates of these adverse outcomes disappeared with a qualified provider.

The proof of the pudding lies in studies free of these weaknesses. A study of 530,000 low-risk Dutch women found no difference in deaths during labor or newborn death rates between women planning, but not necessarily having, home birth and those planning hospital birth (de Jonge 2009). A Canadian study comparing outcomes of 2900 women eligible for home birth with women equally eligible but planning hospital birth reported worse newborn outcomes (more required resuscitation at birth or oxygen for more than 24 hrs and more birth injuries), worse maternal outcomes (more anal sphincter tears and postpartum hemorrhage), and more use of instrumental and cesarean delivery in the hospital population (Janssen 2009).

What can we take away from Cheng and colleagues analysis? First, care provider qualifications matter. Women desiring home birth should have access to professional midwifery care, which argues for making CPMs legal in all 50 states. Second, less than optimal candidates are birthing at home, and some women may be continuing labor at home who shouldn’t. Why might that be? Women may choose home birth because they want control over what happens to them, they have had a prior negative hospital experience, or they want to avoid unnecessary medical intervention (Boucher 2009), the last of which will include women denied hospital VBAC. Women may resist hospital transfer for the same reasons or because they know that at best, hospital transfer means losing the care and advice of the care provider they trust and at worst, they will be treated badly by disapproving hospital staff. If we want to reduce their numbers, hospital-based practitioners need to address the behaviors, practices, and policies that drive women away from hospital birth. This would have the added benefit of improving care for the 99% of American women who would never consider birthing at home.

References

Boucher, D., Bennett, C., McFarlin, B., & Freeze, R. (2009). Staying home to give birth: why women in the United States choose home birth. J Midwifery Womens Health, 54(2), 119-126. http://www.ncbi.nlm.nih.gov/pubmed/?term=boucher+2009+home+birth

Cheng, Y. W., Snowden, J. M., King, T. L., & Caughey, A. B. (2013). Selected perinatal outcomes associated with planned home births in the United States. Am J Obstet Gynecol, 209(4), 325 e321-328. doi: 10.1016/j.ajog.2013.06.022 http://www.ncbi.nlm.nih.gov/pubmed/23791564

de Jonge, A., van der Goes, B. Y., Ravelli, A. C., Amelink-Verburg, M. P., Mol, B. W., Nijhuis, J. G., . . . Buitendijk, S. E. (2009). Perinatal mortality and morbidity in a nationwide cohort of 529,688 low-risk planned home and hospital births. BJOG 116(9), 1177-1184. http://www.ncbi.nlm.nih.gov/pubmed/?term=de+jonge+2009+planned+home

Janssen, P. A., Saxell, L., Page, L. A., Klein, M. C., Liston, R. M., & Lee, S. K. (2009). Outcomes of planned home birth with registered midwife versus planned hospital birth with midwife or physician. CMAJ, 181(6-7), 377-383. http://www.ncbi.nlm.nih.gov/pubmed/19720688

 

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Does the Hospital “Admission Strip” Conducted on Women in Labor Work as Hoped?

October 3rd, 2013 by avatar

The 20 minute electronic fetal monitoring strip is a “right of passage” for any woman being admitted to the hospital in labor.  But is this automatic 20 minute strip evidence based?  Regular Science & Sensibility contributor Henci Goer takes a look at a recent Cochrane systematic review and lets us know what the research says.  Do you discuss this with your students?  Do you share about this practice  in your classes and with your patients and students?  What do you tell them? Will it change after reading Henci’s review below? – Sharon Muza, Science & Sensibility Community Manager

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© http://www.flickr.com/photos/jcarter

Some weeks ago, I did a Science and Sensibility post summarizing the latest version of the Cochrane systematic review of continuous electronic fetal monitoring (EFM)—AKA cardiotocography (CTG)—in labor versus intermittent listening. A couple of commenters on that post asked if I would tackle the “admission strip,” the common practice of doing EFM for 20 minutes or so at hospital admission in labor to see whether ongoing continuous monitoring is warranted.

I was in luck because the Cochrane Library has a recent systematic review of randomized controlled trials of this practice versus intermittent listening in women at low risk for fetal hypoxia (Devane 2012). The rationale for the admission strip, as the reviewers explain, is that pregnancy risk factors don’t predict all babies who will experience morbidity or mortality in labor. The admission strip is an attempt to identify women free of risk factors whose babies nevertheless might benefit from closer monitoring. Let’s see whether the admission strip succeeds at identifying those babies and improving their outcomes.

As to whether the admission strip identifies babies believed to be in need of closer surveillance, the answer is “yes.” Pooled analysis (meta-analysis) of the trials found that 15 more women per 100 allocated to the admission strip group went on to have continuous EFM (3 trials, 10,753 women), and 3 more babies per 100 underwent fetal blood sampling (3 trials, 10,757 babies).

Furthermore, women almost certainly underwent more cesareans as well (4 trials, 11,338 women). All four trials reported more cesareans in the admission strip group. The pooled increased risk of 20% just missed achieving statistical significance, but this is probably because cesarean rates were so low, only 3 to 4% in by far the biggest trial, which contributed 8056 participants. Because of the lack of heterogeneity among trials, the reviewers think the difference is likely to be real. If it is, then using an admission strip in low-risk women results in 1 additional cesarean for every 136 women monitored continuously (number needed to harm). I would add that not separating out first-time mothers, who are at greater risk for cesarean delivery, probably masked a bigger effect in this subgroup. How big an effect might this be?  Let’s assume a 9% cesarean rate in low-risk first-time mothers, that being the rate found  in first-time mothers still eligible for home birth at labor onset in the Birthplace in England study (2011). At this cesarean rate, a 20% increase over baseline would calculate to 1 additional cesarean for every 55 first-time mothers monitored continuously.

The crucial question, though, is whether increased monitoring and surgical deliveries produced better perinatal outcomes. To that, the answer is “no.” Combined fetal and neonatal death rates in infants free of congenital anomalies were identical at 1 per 1000 in both groups (4 trials, 11,339 babies). The reviewers acknowledge that their meta-analysis of over 11,000 babies is still “underpowered,” i.e., too small to detect a difference in outcomes. However, they continue, the event is so rare in low-risk women that no trial or meta-analysis would likely be big enough to do so. Additionally, no differences were found for cases of hypoxic ischemic encephalopathy (1 trial, 2367 babies), admissions to neonatal intensive care (4 trials, 11,331 babies), neonatal seizure (1 trial, 8056 babies), evidence of multi-organ compromise within the first 24 hours (1 trial, 8056 babies), or even 5-minute Apgar scores less than 7 (4 trials, 11,324 babies).

The reviewers therefore conclude:

We found no evidence of benefit for the use of the admission CTG for low-risk women on admission in labour. Furthermore, the probability is that admission CTG increases the caesarean section rate by approximately 20%. . . . The findings of this review support recommendations that the admission CTG not be used for women who are low risk on admission in labour. Women should be informed that admission CTG is likely associated with an increase in the incidence of caesarean section without evidence of benefit (Devane 2012, p. 2). [Emphasis mine.]

Conclusion

According to the best evidence, the admission strip isn’t just ineffective, it’s harmful, and its use should be abandoned

References

Birthplace in England Collaborative Group. (2011). Perinatal and maternal outcomes by planned place of birth for healthy women with low risk pregnancies: the Birthplace in England national prospective cohort study. BMJ, 343, d7400.  http://www.ncbi.nlm.nih.gov/pubmed/22117057?dopt=Citation

Devane, D., Lalor, J. G., Daly, S., McGuire, W., & Smith, V. (2012). Cardiotocography versus intermittent auscultation of fetal heart on admission to labour ward for assessment of fetal wellbeing. Cochrane Database Syst Rev, 2, CD005122. doi: 10.1002/14651858.CD005122.pub4 http://www.ncbi.nlm.nih.gov/pubmed/22336808

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