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Elective Induction at Term Reduces Perinatal Mortality Without Increasing Operative Delivery? Looking Behind the Curtain

May 29th, 2012 by avatar

A recent study of elective induction at term purports to show that it would reduce perinatal mortality without affecting spontaneous birth rates, although it would increase admission to a special neonatal care unit if done before 41 weeks. The study, conducted in Scotland, analyzed outcomes of 1,271,549 women carrying a singleton, head-down baby of 37 to 40 weeks gestation who gave birth between 1981 and 2007. (Forty-one weeks was considered postterm.) Women with prior cesarean, breech baby, or placenta previa were excluded. Elective induction was defined as induction with no medical indications (hypertensive or kidney disorders, thromboembolic disease, diabetes, liver disorders, pre-existing medical disorder, antenatal investigation of abnormality, suspected fetal abnormality, fetal compromise, or previous stillbirth or neonatal death), and 176,136 women met these criteria. Perinatal mortality was defined as stillbirth or death within the first month, excluding deaths associated with congenital anomalies. Outcomes were adjusted for maternal age, parity (no prior births vs. one or more prior births), time period, and birth weight.

Investigators reported outcomes by week in two ways: women electively induced compared with women not electively induced who delivered after that week and women electively induced compared with women not electively induced who delivered in or after that week. I will report outcomes according to the second method because it is less biased.

Perinatal mortality rates declined from 2.4 per 1000 at 37 weeks to 1.6 per 1000 at 41 weeks in the “not electively induced” population and varied from 0.9 to 0.6 per 1000 in the electively induced population, showing no trend, which meant that the excess

Drewesque, via Flickr, Creative Commons Attribution

perinatal mortality rate fell from 2.3 per 1000 more deaths at 37 weeks in the “not electively induced” population to 0.9 more at 41 weeks. That would seem to clinch the argument for elective term induction were it not for one fatal flaw: investigators did not compare similar populations. They isolated a low-risk—I may even say ultra-low-risk—group of women and compared them with everyone else, including women with the high-risk conditions listed above! Finding lower perinatal mortality rates should not be surprising. It would have been extraordinary if they had not.

Even with that advantage, more babies were admitted to special or intensive care nurseries after elective induction at every week through 40 weeks, which contradicts the current belief that elective delivery at 39 weeks poses no excess risk. Excesses declined from 94 more babies per 1000 with elective induction at 37 weeks to 10 more babies per 1000 at 40 weeks. (At 41 weeks, 3 more babies per 1000 were admitted to special or intensive care in the “not electively induced” population.)

What about finding similar spontaneous vaginal birth rates? Spontaneous birth rates were, indeed, similar between groups, but more women delivered via cesarean surgery in the electively induced group. Depending on the week, 0.3 to 1.5 more women per 100 electively induced had cesareans. Spontaneous birth rates were similar because the cesarean excess was offset by an excess of instrumental vaginal deliveries at each week in the “no elective induction” group. An excess of instrumental deliveries is concerning primarily because of the increased likelihood of anal sphincter injury; however, an excess in cesarean deliveries is far more serious, carrying as it does increased likelihood of severe maternal and perinatal morbidity and mortality in both current and future pregnancies.

Rob, Joyce, Alex & Nova's photostream, via Flickr, Creative Commons Attribution

Rob, Joyce, Alex & Nova's photostream, via Flickr, Creative Commons Attribution

Furthermore, the investigators chose not to report cesarean rates according to parity. Women with a prior vaginal birth or births will be little affected by induction, but first-time mothers are a different story. Studies (see references below) comparing term elective induction with spontaneous onset report that elective induction roughly doubles the chance of cesarean with excesses ranging from 3 to 31 more women per 100 having labor end in cesarean. Three studies (Hannah et al. 1996, Kassab et al, 2011; Pavicic et al. 2009.) specifically evaluating elective induction at 41 weeks compared with expectant management for at least one more week in low-risk first-time mothers report a remarkably similar excess: 8 to 9 more cesareans per 100 women induced electively. In first-time mothers, then, the excess cesarean surgery rate was almost certainly much greater than the excess rate in the Scottish population overall.

So there you have it. Does elective induction at term save babies? We don’t know because the investigators compared apples to oranges. It certainly increases likelihood of admittance to special or intensive neonatal care through 40 weeks, an excess all the more ominous because comparison women were not all low risk. It’s also a safe bet that it substantially increases cesarean surgery rates in first-time mothers going by what other studies have found. And, again, the excess would likely have been greater even in the population overall had investigators compared low-risk women to low-risk women. Lesson learned: if you don’t look at what’s behind the curtain, you may get very misleading ideas of what is really going on.

Boulvain, M., Marcoux, S., Bureau, M., Fortier, M., & Fraser, W. (2001). Risks of induction of labour in uncomplicated term pregnancies Paediatr Perinat Epidemiol, 15(2), 131-138.

Cammu, H., Martens, G., Ruyssinck, G., & Amy, J. J. (2002). Outcome after elective labor induction in nulliparous women: A matched cohort study. Am J Obstet Gynecol, 186(2), 240-244.

Dublin, S., Lydon-Rochelle, M., Kaplan, R. C., Watts, D. H., & Critchlow, C. W. (2000). Maternal and neonatal outcomes after induction of labor without an identified indication. Am J Obstet Gynecol, 183(4), 986-994.

Ehrenthal, D. B., Jiang, X., & Strobino, D. M. (2010). Labor induction and the risk of a cesarean delivery among nulliparous women at term. Obstet Gynecol, 116(1), 35-42.

Glantz, J. C. (2005). Elective induction vs. Spontaneous labor associations and outcomes. J Reprod Med, 50(4), 235-240.

Le Ray, C., Carayol, M., Breart, G., & Goffinet, F. (2007). Elective induction of labor: Failure to follow guidelines and risk of cesarean delivery. Acta Obstet Gynecol Scand, 86(6), 657-665.

Luthy, D. A., Malmgren, J. A., & Zingheim, R. W. (2004). Cesarean delivery after elective induction in nulliparous women: The physician effect. Am J Obstet Gynecol, 191(5), 1511-1515.

Macer, J. A., Macer, C. L., & Chan, L. S. (1992). Elective induction versus spontaneous labor: A retrospective study of complications and outcome. Am J Obstet Gynecol, 166(6 Pt 1), 1690-1696; discussion 1696-1697.

Maslow, A. S., & Sweeny, A. L. (2000). Elective induction of labor as a risk factor for cesarean delivery among low-risk women at term. Obstet Gynecol, 95(6 Pt 1), 917-922.

Prysak, M., & Castronova, F. C. (1998). Elective induction versus spontaneous labor: A case-control analysis of safety and efficacy. Obstet Gynecol, 92(1), 47-52.

Seyb, S. T., Berka, R. J., Socol, M. L., & Dooley, S. L. (1999). Risk of cesarean delivery with elective induction of labor at term in nulliparous women. Obstet Gynecol, 94(4), 600-607.

Vahratian, A., Zhang, J., Troendle, J. F., Sciscione, A. C., & Hoffman, M. K. (2005). Labor progression and risk of cesarean delivery in electively induced nulliparas. Obstet Gynecol, 105(4), 698-704.

van Gemund, N., Hardeman, A., Scherjon, S. A., & Kanhai, H. H. (2003). Intervention rates after elective induction of labor compared to labor with a spontaneous onset. A matched cohort study. Gynecol Obstet Invest, 56(3), 133-138.

Vardo, J. H., Thornburg, L. L., & Glantz, J. C. (2011). Maternal and neonatal morbidity among nulliparous women undergoing elective induction of labor. J Reprod Med, 56(1-2), 25-30.

Vrouenraets, F. P., Roumen, F. J., Dehing, C. J., van den Akker, E. S., Aarts, M. J., & Scheve, E. J. (2005). Bishop score and risk of cesarean delivery after induction of labor in nulliparous women. Obstet Gynecol, 105(4), 690-697.

Yeast, J. D., Jones, A., & Poskin, M. (1999). Induction of labor and the relationship to cesarean delivery: A review of 7001 consecutive inductions Am J Obstet Gynecol, 180(3 Pt 1), 628-633.

Cesarean Birth, Do No Harm, Evidence Based Medicine, Guest Posts, Healthy Birth Practices, Healthy Care Practices, Maternity Care, Medical Interventions, New Research, Research, Uncategorized , , , , , , , , , ,

How Long Can Labor Safely Be?

April 18th, 2012 by avatar

How Long Can Labor Safely Be?

By regular contributor, Henci Goer

A few weeks ago Kathy Morelli wrote an S&S blog post about a study comparing labor patterns in the 1960s with labor patterns today. The contemporary data were collected by the U.S. Consortium on Safe Labor (CSL), a collection of 19 hospitals, 17 of them teaching institutions, whose primary purpose is “to describe contemporary labor progression and to evaluate the timing of Cesarean delivery in women with labor protraction and arrest.” The study compared women with spontaneous labor onset at term who were carrying singleton, head-down babies and found that after adjustment for differences in maternal and pregnancy characteristics, labors take longer today despite substantially increased use of oxytocin augmentation. The authors attributed the increased length to changes in management practices and concluded: “Since labor times are longer today than in the past, the benefit of extensive interventions such as oxytocin and cesarean delivery in modern labor management needs further evaluation”(Laughon, Branch, Beaver and Zhang, p. 14).

The question still on the table is at what point does increased risk of morbidity from continuing a prolonged labor outweigh the risks of cesarean surgery or instrumental vaginal delivery to curtail it? The CSL study doesn’t answer that question, but we have two studies, one in a single institution and the other a multicenter study, that provide means and extremes for duration of physiologic labor. Both studies were conducted in healthy women in spontaneous labor at term with a singleton, head down fetus who were cared for by midwives. No woman had oxytocin augmentation, epidural analgesia, or an instrumental vaginal or cesarean delivery. Let’s compare data on first-time mothers since they are much more likely to experience progress delay.

 

CSL
n = 43,576

Albers 1999
n = 806

Albers 1996
n = 556

4 cm -> 10 cm
CSL: median (95th percentile)*
Albers: mean (95th percentile)
6.5 (24.0) hr 7.7 (17.5) hr 7.7 (19.4) hr
2nd stage
CSL: median (95th percentile)**
Albers: mean (95th percentile)
0.9 (3.1) hr 0.9 (2.4) hr 0.9 (2.5) hr
epidural 60% 0% 0%
oxytocin augmentation 37% 0% 0%
instrumental vaginal delivery 10% 0% 0%
intrapartum cesarean 16% 0% 0%
5-min Apgar < 7 2% 0.8% 1.1%

*data only from women reaching full dilation
** data only from women having spontaneous birth

As you can see, labor averaged even longer in the physiologic groups without doing any harm to the newborns. As you can also see, the midwifery data blow active management concepts, now enshrined in partograms, out of the water. Setting 1 cm per hour as the threshold for abnormally slow progress—which allows 6 hours to go from 4 cm to 10—means augmenting first-time mothers dilating faster than the average rate!

The CSL investigators point out that half the cesareans in the entire CSL cohort were performed for “failure to progress” or “cephalopelvic disproportion” and reference another study of the cohort finding that “a large percentage of women” (p. 12) had cesareans prior to active-phase labor. Indeed they did. Among first-time mothers with spontaneous labor onset who had cesareans for delayed progress, more than a quarter of them (28%) had the surgery at 5 cm dilation or less. Among induced labors, the percentage soared to half (53%).

Despite their concern about over use of oxytocin augmentation and operative delivery, the CSL investigators also note that the extra two hours of average labor duration in first-time mothers (compared with the 1960s cohort) cost Intermountain Healthcare hospitals, which managed 5439 vaginal births in first-time mothers in 2010, an extra $110.40 per labor, amounting to an annual excess cost of $600,466. They continue: “The implications for healthcare systems and payors are obvious and should drive a reconsideration of modern-day labor process management with an eye towards process improvement” (p. 13). One wonders just what that process improvement might be. The “time is money” argument certainly doesn’t augur for recommendations to have patience and avoid intervening—especially not when intervening via cesarean surgery increases revenue as well as saves money.

They don’t come right out and say so, but clearly the CSL investigators know they have documented a gross overuse of cesarean surgery to cut short (pun intended) perfectly normal labors that pose no excess risk to mothers or babies. The Consortium on Safe Labor has, in fact, exposed that labor in their participating hospitals isn’t very . . . well, . . . safe. Women are ending up with major interventions they don’t really need and, no doubt, some of them are experiencing unnecessarily their consequent complications. What is more, economics provides a perverse incentive for keeping it that way.

 

 

Authoritative Knowledge, Cesarean Birth, Systematic Review, Uncategorized , , ,

Pain Management for Women in Labor: A Research Review

April 11th, 2012 by avatar

As a childbirth professional or an expectant parent, do you wonder about the multitude of pain management techniques offered for childbirth?

As part of the Cochrane Collaboration, Leanne Jones and eight of her colleagues (2012) has published new research synthesizing divergent data constructs and summarizing 355 trials on pain management during childbirth. There are many detailed data tables associated with this study.

To view the entire study, Lamaze members can access the full Cochrane Library, via the Members Only Section.

A summary of the study is below.

Background

In 2007, the Cochrane Pregnancy & Childbirth Group (PCG) consumer’s group identified pain relief in childbirth as the topic of most importance to them.

This study was funded to provide an evidence-based summary of the efficacy and safety of pain management methods in childbirth for consumers, policy-makers, and childbirth educators.

Women experience pain in childbirth in varying degrees of intensity, influenced by physiological and psychosocial factors. Most women require some type of pain relief. Both non-pharmacological and pharmacological methods are used for pain management.

312 Studies Reviewed

Collecting the totality of evidence from existing randomized controlled trials, the researchers identified 18 total systematic reviews for inclusion in their study. 15 reviews were Cochrane reviews (257 included trials) and 3 were non-Cochrane reviews (55 included trials). Data from a total of 312 studies were reviewed in this study.

There were more studies of pharmacological interventions than non-pharmacological interventions.

13 Outcomes Identified for Inclusion

The researchers, in partnership with the PCG consumer group, identified these outcomes for inclusion in the study.

Effects of interventions

  • Pain intensity (as defined by trialists)
  • Satisfaction with pain relief (as defined by trialists)
  • Sense of control in labor (as defined by trialists)
  • Satisfaction with childbirth experience (as defined by trialists)

Safety of interventions

  • Effect (negative) on mother/baby interaction
  • Breastfeeding (at specified time points)
  • Assisted vaginal birth
  • Cesarean section
  • Adverse effects (for women & babies)
  • Admission to special care baby unit / NICU
  • Apgar score less than at five minutes
  • Poor infant outcomes at long-term follow-up (as defined by trialists)

15 Childbirth Management Methods Identified

The researchers identified a list of 15 childbirth pain management methods:

  • placebo/no treatment
  • hypnosis
  • biofeedback
  • intracutaneous or subcutaneous sterile water injection
  • immersion in water
  • aromatherapy
  • relaxation techniques (yoga, music, audio)
  • acupuncture or acupressure
  • massage, reflexology or manual methods
  • TENS
  • inhaled analgesia
  • opioid
  • non-opioid drugs
  • local anesthetic nerve blocks
  • epidural

 As a Lamaze childbirth educator, how will you incorporate respect for your client’s individual decisions while presenting the Six Lamaze Healthy Birth Practices?

Results: Non-pharmacological Studies

The authors found that non-pharmacological methods are mostly used in midwife-led continuity of care births and/or where women had continuous intrapartum support. Such non-pharmacological methods are meant to break the fear-pain-tension cycle and to work within the pain paradigm. The pain paradigm of birth is a philosophy based on the idea that pain is a normal part of the physiology of labor and that women can use coping methods to manage the pain (Leap, 2008; as cited in Jones et al, 2012).

The researchers found the evidence for many non-pharmacological methods to be mostly incomplete as there is an average of only two studies for each method.

However, the following non-pharmacological methods are shown to provide pain relief and positive maternal psychological outcomes without invasive side effects: immersion in water, relaxation, acupuncture/acupressure and massage.

In addition, women report greater emotional satisfaction with childbirth when using immersion and relaxation. With the use of relaxation and acupuncture/acupressure, there is a decrease in the use of forceps and ventouse. There is a decrease in the amount of cesarean section associated with the use of acupuncture/acupressure.

The researchers report there is insufficient evidence to report on pain relief using the following methods: hypnosis, biofeedback, sterile water injection, aromatherapy and TENS.

Results: Pharmacological Studies

There are more studies of pharmacological methods versus non-pharmacological methods. The authors found that pharmacological methods relieve pain and have side effects.

Pharmacological methods are most likely to be used in settings with a pain relief paradigm. In the pain relief paradigm of labor, pain is considered barbaric, the benefits of analgesia outweigh the risks, and women should be free to use whatever pain relief methods she wishes, without guilt (Leap, 2008; as cited in Jones et al, 2012).

Comparative Pain Relief & Side Effects

Epidural, combined spinal epidural (CSE) and inhaled nitrous oxide & oxygen relieve pain better when compared to opioids (Jones et al, 2012).

Epidurals are associated with an increase of the use of forceps or ventouse, an increase in the risk of low blood pressure, low motor blocks, fever and urine retention (Amin-Somanuh, 2005; as cited in Jones et al, 2012). In addition, other side effects such as shivering, tinnitus, and respiratory or cardiovascular depression may occur. The authors state it is uncertain whether the use of epidurals interfere with breastfeeding (Reynolds, 2011; as cited in Jones et al, 2012).

Combined spinal epidurals (CSE) provide faster pain relief than traditional epidurals, but are associated with more feelings of itchiness, giddiness, sweating, and tingling (Jones et al, 2012).

Inhaled nitrous oxide is associated with minimal toxicity and rapid maternal and neonate elimination, but can cause feelings of nausea, drowsiness and sickness (KNOV, 2009; Rosen, 2002; as cited in Jones et al, 2012).

Non-opioid drugs (acetaminophen and non-steroidal anti-inflammatory drugs (NSAIDS)) relieve pain for shorter periods of time as compared to opioid drugs (Bayarski, Hebbes, 200; as cited in Jones et al, 2012).

Opioid drugs (morphine, nalbuphine, fentanyl, parenteral and pethidine) are used worldwide. Parenteral opioids are reported to provide less pain relief than epidurals. Side-effects include impaired maternal capacity for decision-making, sedation, hypoventilation, hypotension and urine retention. Opioids readily cross the placenta, thus neonatal respiratory depression and hypothermia are also concerns. Pethidine is shown to affect fetal heart rate variability during labor (Sekhavat, 2009; Solt, 2002; as cited in Jones et al, 2012), thus continuous fetal monitoring is recommended. Neonatal effects are inhibited and early cessation of breastfeeding and decreased alertness (Nissen, 1995; Ransjo-Arvidsen, 2001; Righard, 1990; Rajan, 1994; as cited in Jones et al, 2012).

Limitations Found in the Studies

The authors state the studies use differing methods to measure pain management outcomes. Many do not at all measure maternal psychological outcomes (feelings of intrinsic self-control), mom-baby interaction, or breastfeeding and infant outcomes.

Conclusions

This study shows consumers rate pain management as a high priority in childbirth, however, after 30 years of research, standardized pain management and outcome measurements have not been created.

The authors suggest their outcome guidelines, developed with consumer input, be adopted for use in future research.

Overall, women should feel free to choose whatever methods of pain relief they wish, both non-pharmacological and pharmacological, for their individual childbirth experience.

As part of a childbirth preparation program, women should be informed of the efficacy and potential side-effects on both themselves and their babies of non-pharmacological and pharmacological methods of pain relief for childbirth.

Hopefully this study will generate an effort to standardize the constructs associated with research of measurements of pain management in labor, maternal psychosocial satisfaction, and maternal-baby outcomes.

References

Jones L, Othman M, Dowswell T, Alfirevic Z, Gates S, Newburn M, Jordan S, Lavender T, Neilson JP. Pain management for women in labour: an overview of systematic reviews. Cochrane Database of Systematic Reviews 2012, Issue 3. Art. No.: CD009234. DOI: 10.1002/14651858.CD009234.pub2

Babies, Cesarean Birth, Do No Harm, Epidural Analgesia, Evidence Based Medicine, Fetal Monitoring, Healthy Birth Practices, informed Consent, Medical Interventions, Midwifery, New Research, News about Pregnancy, Pain Management, Practice Guidelines, Research , , , , , , , , ,

Changes in Labor Patterns Over 50 Years – A Research Review

April 2nd, 2012 by avatar

New research was published in the American Journal of Obstetrics and Gynecology. Katherine Laughon, MD, and her colleagues, D. Ware Branch, M.D., Julie Beaver, M.S, and Jun Zhang, Ph.D., M.D., (2012) examined differences in childbirth labor patterns over the past fifty years, comparing data from a large study in the 1960′s with data from a large study in the 2000′s.

The researchers found differences both in maternal characteristics and obstetric practice patterns. In the contemporary cohort, the authors found an increase in first stage labor of over two hours and a cesarean section rate four times as high as in the past cohort. In the cohort from the 1960′s, a higher operative vaginal delivery rate was found as compared to the contemporary cohort. The authors link these differences to changes in obstetric practice patterns. The authors state that even after controlling for maternal and obstetrician characteristics, the increased length of labor result for the contemporary cohort persists (Laughon, Branch, Beaver and Zhang, 2012).

Positive Action Items for Moms and Childbirth Educators

The National Institute of Child Health and Human Development (NICHD)ran a conference call on March 31, 2012, where Katherine Laughon, MD, the lead researcher on the study, gavea brief overview of the study and answered questions. Robin Elise Weiss, LCCE, was on the call and summarized Dr. Laughon’s positive steps to take by women and childbirth educators who are interested in natural childbirth. Dr. Laughon’s suggestions fall into Lamaze’s Six Healthy Birth Practices.

  • These women might be comfortable waiting longer to get pitocin and other interventions, including cesareans.
  • Choose your practitioner carefully. Dr. Laughon suggests a practitioner should be able to think about the differences in labor patterns in modern times, not from textbooks.
  •  Remember there is not an ideal length of labor, long or short. It is based on the individual, woman to woman and baby to baby.

 As a Lamaze childbirth educator, do the results of this study surprise you?

What does this mean to you and the families you serve?

Below is a synopsis of the study methods, statistics and conclusions.

Study Design: Comparing Data from the 1960′s to Data from 2000′s

The researchers compared the data from the National Collaborative Perinatal Project (CPP) dating from 1959 – 1966 to the data from the Consortium on Safe Labor (CSL), dating from 2002- 2008. Data from a combined total of 137,850 women from the two studies were included in the 2012 study.

National Collaborative Perinatal Project (CPP) 1959-1966

The CPP (1959-1966) was a prospective study following 54,000 births to 44,000 women. Twelve university centers across the country enrolled pregnant women and collected data such as demographics, medical history, socioeconomic status, behaviors, blood samples, and information from regular physical exams, did interviews and gathered information from the senior obstetrician. The children were followed for seven years after birth. Laughon and her colleagues (2012) limited the use of the CPP data to only women known to be birthing for the first time. Thus, the 2012 study included data from 39,491 women from the CPP study.

Consortium on Safe Labor (CSL) 2002-2008

The CSL (2002 – 2008) was a retrospective cohort study of 228,668 births, with the majority of births (87%) occurring between 2005 and 2007. Information was examined from 12 clinical centers and 19 hospitals in 9 American College of Obstetrics and Gynecology (ACOG) districts. Data was extracted from both the electronically held maternal medical files and neonatal intensive care units. Data on demographics, medical history, maternal and neonatal outcome, and discharge disposition were extracted from the electronic files. Investigators at delivery sites collected information on obstetrician characteristics. Laughon and her colleagues (2012) limited their use of the CSL data to only those women in spontaneous labor with a single gestation. Thus, the 2012 study examined 98,359 women from the CSL study, inclusive of a total of 137,850 women from both the CPP and CSL dataset.

Results: Differences in Characteristics of the Women

Characteristics of the women, of their labors and of their newborns differed significantly between the earlier CPP and the contemporary CSL study.

Women in the CSL were older than in the CPP (26.8 years vs. 24.1), had a higher average BMI both pre-pregnancy (26.3 vs 24.1) and at delivery (29.9 vs 26.3), were more racially diverse, and delivered an average of 4.9 days earlier. Their babies weighed an average of 99 grams (3.48 ounces) more and Apgar scores were higher in the CLS than the CPP.

Results: Differences in Practice Patterns

Use of epidurals (55% vs. 12%), oxytocin (44% vs. 12%); and cesarean delivery (12% vs. 3%) was higher in the contemporary CSL cohort than the CPP. Cesarean delivery in the contemporary cohort is four times as high as in the 1960′s cohort.

Episiotomy (68% vs. 17%) and operative vaginal delivery (40% vs. 6%) were higher in the 1960′s CPP cohort than the contemporary CSL.

Results: First Stage – Differences in Length of Labor

For nulliparas, the first stage of labor (from 4 cm to completely dilated) was 2.6 hours longer in the contemporary cohort (CSL) than the former cohort (CPP).

For secundagravidas and multigravidas, the length of labor was, on average, 2.0 hours longer for the CSL cohort than the CPP cohort.

Results: Second Stage – Differences in Length of Labor

For nulliparas, in the second stage of labor, in the CLS cohort, there was a 10% operative vaginal delivery rate compared to 66% of the CPP cohort. Among women who spontaneously delivered, there was an increase of 27 minutes in the CSL group as compared to 13 minutes in the (CPP group.

Operative vaginal delivery, in secundagravidas and multigravidas, occurred in the CSL 4% and 2.5 % compared to 36% and 18% in the CPP. In secunagravidas and multigravidas, second stage labor did not have a clinically relevant difference in length of labor between the two groups.

Conclusion

The authors state firm conclusions merit further study.

In summary:

“…for women who presented in spontaneous labor at term, the duration of labor from 4 cm to 5 cm in multiparas to complete dilation and the 2nd stages of labor were longer in the contemporary population than a cohort from the 1960s. The overall median differences in the first stage of labor persisted after controlling for maternal and obstetric characteristics, indicating that modern labor differs from the older cohort largely due to changes in obstetric practices. Since labor times are longer today than in the past,the benefit of extensive interventions such as oxytocin and cesarean delivery in modern labor management needs further evaluation.”(Laughon, Branch, Beaver and Zhang, p. 14).

Hopefully this study will generate increased study of obstetric intervention patterns with an eye towards improved contemporary obstetric process management.

References

Laughon, S.K., Branch, D.W., Beaver, J., Zhang, J., Changes in labor patterns over 50 years, American Journal of Obstetrics and Gynecology (2012), doi: 10.1016/j.ajog.2012.03.003.

Many thanks to Robin Elise Weiss, LCCE, who graciously helped out with her reporting expertise on this post!

Cesarean Birth, Childbirth Education, Evidence Based Medicine, Practice Guidelines, Research , , , , , ,

Is Elective Repeat Cesarean Surgery Truly Safer Than Planned VBAC?

March 28th, 2012 by avatar

The headline on a recent BBC News health article reads: “Planned repeat C-sections ‘safer.’ The article goes on to report on two studies that appear to support that conclusion, but do they really? Let’s see what the article says and follow with a look at the actual studies.

One of the studies, the BBC News article tells us, is a U.K. study of 159 cases of uterine rupture in which 139 occurred in women with a prior cesarean. The risk of scar rupture in women with a prior scar, it reports, was seven times greater in women having VBAC labors compared with women planning repeat cesareans, and the risk of the baby dying was three times higher.

That would seem to make a clear case for elective (no medical indication) repeat cesarean (ERC), but if we turn to the study itself, we find that the risk of scar rupture in a VBAC labor was 2 per 1000 VBAC labors versus 0.3 per 1000 planned repeat cesareans, or roughly 2 more scar ruptures per 1000 VBAC labors, not the large difference that “seven times greater” suggests. Moreover, the likelihood of scar rupture was influenced by modifiable factors. The use of prostaglandin, oxytocin, or both for initiating or augmenting labor increased the risk without improving the VBAC rate. In fact, misoprostol was the induction agent in 18% of induced women experiencing scar rupture, but none of the women not having scar rupture were given this agent. ACOG’s 2006 induction guidelines for VBAC labors prohibits using misoprostol because of its strong association with scar rupture. Furthermore, study authors theorize that one reason the scar rupture rate was so low in their study compared with some others was because double-layer uterine suturing, another modifiable practice, is the norm in the U.K..

As for VBAC labor tripling the rate of perinatal (intrapartum + neonatal) death compared with ERC, the study doesn’t give us this number (or maternal morbidity or mortality rates either, for that matter). The study actually only reports maternal and perinatal outcomes in the population overall, which included 20 women with rupture of an unscarred uterus, an event that may be more likely to produce severe adverse outcomes than a scar rupture. In addition, some of the neonatal deaths in women with prior cesarean may have been in women having emergent nonlabor cesareans. For example, three women had a scar rupture in conjunction with placenta previa. The extensive NIH systematic review  of VBAC reported that 6% of babies died as a result of scar rupture in a VBAC labor. We can use that number to calculate the odds of a baby dying in a VBAC labor in the U.K. study by multiplying it (0.06) by the U.K. study’s scar rupture rate (0.002). The result equals 0.00012 or 1 perinatal death per 10,000 VBAC labors. To be sure, every death is a tragedy, but we must also put this into perspective: that mortality is equivalent to the maternal mortality rate with ERC, which is 3 per 10,000, and much less than the fetal loss rate as a result of having an amniocentesis, which one modern-day study found to be 60 per 10,000.

The other study, according to the BBC News article, is an Australian study  of more than 2000 women planning their second delivery after a first cesarean. The BBC article states that the planned VBAC group had more stillbirths, and women were more likely to have severe bleeding, but gives no numbers.

Again, let’s turn to the actual study. The two planned VBAC deaths were unexplained fetal demises in infants born at 39 weeks, the implication being that ERC before that gestational age would have averted them. Perhaps they would have, but as the study  I analyzed in another blog post found, ERC at 39 weeks would have prevented only two of the six antepartum deaths.

The excess in severe hemorrhage (defined as > 1500 ml or transfusion) amounted to 1.5 more instances per 1000 VBAC labors, again, a small absolute difference, and a difference, moreover, that probably would have favored planned VBAC had not so few women had vaginal births. Maternal morbidity mostly occurs in labors that end in intrapartum cesareans, and the VBAC rate in this study was a dismal 43%. With physiologic care, the rate could have been as high as 81%. Even with typical management, studies have reported rates ranging from 61-72% in women with no prior vaginal births. In any case, however worrisome at the time, no differences were found in permanent sequelae such as hysterectomy.

And there is more: neither these studies nor the BBC news article considers the downstream consequences of accumulating cesarean scars, but they should. Even women who plan no more children may change their minds or continue with an unplanned pregnancy. According to the NIH systematic review, as the number of cesareans rises so does the risk of serious neonatal and maternal morbidity and perinatal mortality. By contrast, once a woman has a VBAC under her belt, so to speak, she is almost certain to go on having uneventful VBACs. Also, the review found that the risk of forming dense adhesions (internal scar tissue) rises with number of cesareans as well, thus increasing the likelihood of chronic pain and making any future abdominal surgery, not just future cesareans, more risky and difficult. Add these considerations into the mix, and the balance tips toward planning VBAC as the safer option for almost all women.

Headlines and articles like the one from the BBC News obstruct informed decision making by obscuring the true degree of comparative risk, and the studies contribute by failing to emphasize that better labor management in the previous delivery and current labor would improve outcomes. Planned VBAC is not without risks, but neither is ERC. Women deserve accurate, complete, and, most importantly, quantified information on which to decide on mode of birth after a cesarean. They also should have care in the primary cesarean that promotes safety in future VBACs and care in VBAC labors that promotes safe, healthy vaginal birth. To do less than that does women and their babies a serious disservice.

Cesarean Birth