24h-payday

Archive

Archive for the ‘Systematic Review’ Category

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 , , , , , , ,

Happy 20th Anniversary to the Cochrane Collaboration!

January 15th, 2013 by avatar

As I wrote about in my January 3rd, 2012 post on the top 10 reasons to join Lamaze International, one of the great benefits of being a Lamaze member is complete access to the Cochrane Collaboration.  The Cochrane Collaboration is an international organization whose purpose is to make available information on the effects of healthcare interventions.  Reports in the form of Cochrane Reviews are current, accurate and made available electronically on the internet and by DVD, and updated monthly.  Systematic reviews are conducted and published on a wide variety of healthcare interventions so that people can make informed decisions. This is stored in the Cochrane Library.

Archie Cochrane, photo credit: Cardiff University. Library, Cochrane Archive, University. Hospital Llandough

The Cochrane Collaboration was founded by Archie Cochrane, who was a British medical researcher.  Mr. Cochrane is best known for his article Effectiveness and Efficiency: Random Reflections on Health Services written in 1972.  

The creation of a systematic review of randomised controlled trials (RCT’s) of care during pregnancy and childbirth is “a real milestone in the history of randomised trials and in the evaluation of care.” Professor Archibald Leman Cochrane, CBE FRCP FFCM, (1909 – 1988)

The Cochrane Collaboration is celebrating their 20th anniversary this year, 2013 and will be sharing a series of 24 short videos over the course of the anniversary year, focusing on the ideas, achievements and people that have been part of the history of this international and well-respected organization.  I am sharing the first in this series, so you can learn a bit more about how this organization came to be recognized as the gold standard in evidence-based health care.

The United States Cochrane Center has created and made available free of charge, an online tutorial, “Understanding Evidence-based Healthcare: A Foundation for Action, that can help you to learn how to best navigate and understand the resources contained in the Cochrane Library.

Lamaze International’s Healthy Birth Practice Tools is completely based on evidence based information and was created so that consumers could understand and advocate for the best care for themselves and their babies.  Lamaze recognizes the importance of educators and others having access to up to date information and therefore is pleased to offer access to the Cochrane Library as a member benefit.   To access the Cochrane Library as a Lamaze member, first login to Lamaze International’s Member Center and then follow the drop down box to the Cochrane Library. You will be redirected to the library, with full access.

I rely on and use this member benefit constantly, and appreciate it being made available to me by Lamaze.  Won’t you share in the comments section how you use the Cochrane Library?  How has it helped you?  Do you find what you need?  Do you share information and studies with your students, clients and patients?  Let us know, please.

References 

Cochrane AL. Effectiveness and Efficiency. Random Reflections on Health Services. London: Nuffield Provincial Hospitals Trust, 1972. (Reprinted in 1989 in association with the BMJ, Reprinted in 1999 for Nuffield Trust by the Royal Society of Medicine Press, London (ISBN 1-85315-394-X)

Childbirth Education, Continuing Education, Evidence Based Medicine, Healthy Birth Practices, Healthy Care Practices, informed Consent, Lamaze International, Maternal Quality Improvement, Maternity Care, Medical Interventions, New Research, Practice Guidelines, Research, Systematic Review , , , , , , , , ,

Book Review: Optimal Care in Childbirth: The Case for a Physiologic Approach Reviewed Through a Childbirth Educator’s Eyes

October 18th, 2012 by avatar

I had waited excitedly for the release of Henci Goer and Amy Romano’s new book for a long time and was delighted to receive it after it was published in May 2012. Optimal Care in Childbirth: The Case for a Physiologic Approach was a robust, updated successor to Henci’s previous book; Obstetric Myths Versus Research Realities which was a well used source on my office bookshelf.

Both authors have a long history with Lamaze International. Prior to her current position with Childbirth Connection, directing the Transforming Maternity Care Partnership, Amy launched Science & Sensibility, and provided a keen and critical eye when analyzing, reviewing and sharing research items with readers. Henci Goer has been the long time resident expert on the “Ask Henci” forum hosted by Lamaze International, providing and sharing resources on a wide variety of pregnancy and childbirth topics with consumers and professionals alike, as well as a regular contributor to this blog. Please read the full bios of Amy and Henci on their website, where you can find complete information on their work, background and other works that they have authored.

As the title clearly states, this book is about childbirth, and as such, you will not find information on pregnancy, breastfeeding or newborn topics. Nor is this the type of text that childbirth educators would hand out in class for consumers to use. This book is heavy with sources, study outcomes and insights into current obstetric practices. But, as a guide to best practice, the book becomes a great repository of information that allows consumers and professionals alike to learn and make decisions about care that can help keep birth as physiological as possible. The book focuses on what factors affect, both positively and negatively, birth, so that an optimal outcome can occur.

The authors define optimal outcomes as “the highest probability of spontaneous birth of a healthy baby to a healthy mother, who feels pleased with herself and her caregivers, ready for the challenges of motherhood, attached to her baby, and goes on to breastfeed successfully.”

The chapters are well organized, with the topic of cesareans starting things off. Cesarean rates have never been higher, and many of the topics that Goer and Romano discuss later in the book often have the unintended consequence of contributing to the skyrocketing cesarean rates in this country. I think it is an important topic and one that receives a thorough evaluation by the authors.

Each chapter starts off with “contradicting” quotes from researchers working in the field of obstetrics, and I have to say, that reading these at the beginning of each chapter was something I looked forward to, a nice added bonus and really made me pause and consider the different viewpoints and how they influence practice today. The lead in for chapter 12 on epidurals and spinals contains one of my favorites:

“There is no other circumstance in which it is considered acceptable for a person to experience untreated severe pain, amenable to safe interventions, while under a physician’s care.” ACOG 2006

“Epidural anaesthesia remains one of childbirth’s best exemplars of iatrogenesis. It is a wonderful intervention for managing labour complications, especially as an alternative to general anaesthetic for caesarean sections, but has significant side effects that constantly need weighing alongside benefits. Though its rising popularity almost grants it the status of normative practice on some [U.K.] maternity unites, it remains incompatable with physiological labour.” Walsh 2007

Each chapter begins with a wonderful perspective on each topic, sharing history and cultural practices so the reader can understand how standard protocols found in most birthing facilities have come to be, even when not backed up by research. I think it is critical to include this information, for if there is to be a shift to more evidence based care in the field of obstetrics, we need to be aware and acknowledge that some practices may have evolved for legal, cultural, social or policy reasons having nothing to do with sound research.

The authors ask and answer the very questions that I find myself asking out loud, helping the reader to understand why we continually observe care that is known to not improve outcomes. For example, when discussing electronic fetal monitoring, the question “Why does use of continuous EFM persist?” in normal low risk labors is asked (and thoroughly answered) with supporting references for further information.

Each chapter contains a brief summary of action steps that women can take to receive optimal care, along with the supporting research that backs up these steps. These lists are great talking points both for educators to integrate in their classrooms, but also for consumers to discuss with their health care providers and understand why their care might deviate from that supported by research.

The conclusion of each chapter has what the authors call a “mini-review” and neatly summarizes the important topic statements and provides (and references) outcomes of studies so that the reader can evaluate for himself or herself the validity of the research. Though these sections are called reviews, I found them to be a very helpful component of the book, when looking for solid sources.

At the end of each chapter, all of the sources referenced in that chapter are listed.

Henci Goer

I was very appreciative throughout the book, for the definitions that the authors provided when discussing a topic. It is important (and helpful) to know how terms are defined, so that the reader can best understand the discussion. For example, in one of the cesarean chapters, one can find a list of “rate” terms, so when “primaparous cesarean rate” is discussed, this term has already been explained.

Several places throughout the book, in various callout boxes, Goer and Romano discussed the selective language that health care providers use when talking about childbirth and presenting information to families. I found these small detours fascinating, as I am very interested in the language that HCPs use to discuss risk, procedures and events with their patients.

The last chapters of the book take a look at choice of birth location, what the ideal maternity care system might include and includes information on maternal mental health. The appendices speak to common “less than optimal” situations, such as the OP fetus in labor, meconium staining and other circumstances that frequently cause concern and labor interventions. Again, the authors include information on optimal care in these cases that can help.

It is clear from some of the phrasing, chapter titles and choice of words in some of the discussions, that the authors have a bias towards a childbirth process that unfolds in a natural and physiological manner. This language, while potentially off-putting to those who firmly believe in the medical model, is effective in causing the reader to consider standard practices that make no logical “sense”, and certainly, references are provided for further research should the reader wish to investigate further.

I must say that I very much enjoyed this book, and I will find it very useful in my doula and Lamaze childbirth education practice. It is the type of book that one thumbs through frequently, when asked a question by a student or client, or when helping a client to prepare to speak to their health care provider about best practices and birth preferences. I think that any birth professional would do well to have this book on their shelf and be able to refer to it when necessary. This book represents a significant amount of research and I find great comfort in knowing that all the resources and references supporting the statements made in the book are available for me to source myself.

Amy Romano

I look forward to the release of the e-book version of this title, expected this fall, for the Kindle, iPad and other tablets, so that I could have easy access from wherever I am. I would be delighted if the references and sources could be routinely updated as new research is released and published, so that I can use this guide for many years to come, confident that it reflects the newest and most valid research. I know that is a formidable task, but I would gladly pay a small subscription fee to have an updated version as often as necessary.

This book is available for purchase from both Amazon.com and the Optimal Care in Childbirth website. The book is on the expensive side, costing approximately $50.00, but very well may become the go-to source for evidenced based research on your office shelf, so worth the investment. If you choose to purchase from the book’s site, there are bulk and wholesale discounts available.  For purchases made from the book’s website, the authors are providing a 15% discount for our Science & Sensibility blog readers and conference attendees. Enter code UXJXI52F at checkout to receive the discount.

I hope that you are planning to attend the upcoming Lamaze International Innovative Learning Forum next week, where both Amy Romano and Henci Goer have been invited to speak. You will have an opportunity to meet these authors, ask them questions, purchase this book and hear their powerful presentations. As a General Session Speaker, Amy’s session will be available as part of the “Virtual Conference” option for those unable to attend the conference in person.

Have you read Optimal Care in Childbirth?  Are you using it already in your practice?  Please share your thoughts and comments in our comment section here on the blog.  I look forward to hearing your views. – SM

References

ACOG committee opinion. No. 339: Analgesia and cesarean delivery rates. Obstet Gynecol 206;107(6):1487-8.

Walsh D. Evidenced Based Care for Normal Labor and Birth. London: Routledge; 2007.

Book Reviews, Cesarean Birth, Childbirth Education, Epidural Analgesia, Fetal Monitoring, Healthcare Reform, informed Consent, Lamaze 2012 Annual Conference, Maternal Mental Health, Medical Interventions, New Research, Pain Management, Practice Guidelines, Research, Systematic Review, Transforming Maternity Care , , , , , , , , ,

What is the Evidence for Induction for Low Amniotic Fluid in a Healthy Pregnancy?

August 30th, 2012 by avatar

By Rebecca L. Dekker, PhD, RN, APRN

Today’s post on the Evidence for Induction for Low Amniotic Fluid in a Healthy Pregnancy is a guest post by blogger Rebecca Dekker, owner of  the fairly new blog in the birth world, Evidence Based Birth that has been  very well received and enjoyed by many.  Look for an interview with Rebecca in an upcoming post where we will learn how this Assistant Professor of Nursing who teaches pathopharmacology and studies depression in patients with heart failure ended up writing the Evidence Based Birth blog appreciated by birth professionals.  I look forward to future posts and collaboration with Rebecca and thank her for her contribution today.- SM

__________________

This question came from one of my readers:

“Low fluid seems to be the new “big baby” for pushing for induction. What does the research say about low fluid at or near term? From what I’ve been able to see in research summaries at least, there appears to be no improved outcome for babies, but I’d love to see the research really hashed out. I’m also curious about causes of low fluid (theorized or known), risks of low fluid, and perhaps as important if not more so, measurements of low fluid.”

This is a great question and I felt like it was a perfect topic for my first article for Science and Sensibility. Standard of practice in the U.S. is to induce labor at term if a mother has low amniotic fluid in an otherwise healthy pregnancy. In fact, 95% of physicians who practice maternal-fetal medicine feel that isolated oligohydramnios—low amniotic fluid in an otherwise healthy pregnancy—is an indication for labor induction at 40 weeks (Schwartz, Sweeting et al. 2009).

But what is the evidence for this standard birth practice? Let’s take a look at the evidence together.

First of all, what is oligohydramnios?

Oligohydramnios means low fluid inside the amniotic sac.

(oligo = little, hydr = water, amnios = membrane around the fetus, or amniotic sac).

Not sure how to pronounce oligohydramnios? Click here.

It is standard of care in the U.S. to induce women with isolated oligohydramnios at term.
Image Source drewesque 

What is amniotic fluid, and what does it do?

During pregnancy, the baby is surrounded by a liquid called amniotic fluid. Amniotic fluid helps protect the baby from trauma to the mother’s abdomen. Amniotic fluid cushions the umbilical cord, protects the baby from infection, and provides fluid, space, nutrients, and hormones to help the baby grow (Brace 1997).

During the second half of pregnancy, amniotic fluid is made up of the baby’s urine and lung secretions. This liquid originally came from the mother, and then flowed through the placenta, to the baby, and out through the baby’s bladder and lungs (Brace 1997).

This same amniotic fluid is then swallowed by the baby and re-absorbed by the lining of the placenta. Because the mother’s fluid levels are the original source of amniotic fluid, changes in the mother’s fluid status can result in changes in the amount of amniotic fluid. Amniotic fluid levels increase until the mother reaches about 34-36 weeks, and then levels gradually decline until birth (Brace 1997).

What can cause low amniotic fluid at term?

Both mother and baby factors can contribute to low amniotic fluid at term.

Mother factors:

  • If the mother is dehydrated, this may lower the amniotic fluid levels. (Patrelli, Gizzo et al. 2012)
  • Women are more likely to be diagnosed with low amniotic fluid levels during the summer, possibly because of dehydration. (Feldman, Friger et al. 2009)
  • If a woman with low amniotic fluid levels at term drinks at least 2.5 Liters of fluid per day, she increases the likelihood that her amniotic fluid levels will be back up to normal by the time of delivery. (Patrelli, Gizzo et al. 2012)
  • If the mother rests on her left side before or during the fluid measurement, this can increase amniotic fluid levels. (Ulker, Temur et al. 2012)
  • If the mother’s water has broken (membranes ruptured), this will lead to a decrease in amniotic fluid. (Brace 1997)
  • If the mother’s placenta is not acting sufficiently anymore, this may lead to a decrease in amniotic fluid. When this happens, it may be because the mother has a serious condition such as pre-eclampsia or intrauterine growth restriction. (Beloosesky and Ross 2012)

Baby factors:

  • If the baby has a problem with the urinary tract or kidneys, this may decrease the flow of urine. (Brace 1997)
  • In the 14 days before the start of spontaneous labor, the baby’s urine output starts to decrease. (Stigter, Mulder et al. 2011)
  • As the baby gets closer to term, the baby swallows more amniotic fluid, thus leading to a decline in fluid levels. (Brace 1997)
  • If the baby is post-term (after 42 weeks), he or she begins to swallow significantly more fluid, contributing to a decline in amniotic fluid. (Brace 1997)
  • If the baby has a birth defect, he or she may swallow significantly more fluid, leading to low amniotic fluid levels. (Beloosesky and Ross 2012)

What is the best way to measure amniotic fluid levels?

The gold-standard method is to inject the amniotic sac with dye and then take samples of the amniotic fluid to check the dilution. However, this method is very invasive. So the most commonly used methods instead are 2 ultrasound techniques:  the amniotic fluid index (AFI) and the single deepest pocket (Gilbert 2012).

To calculate the AFI, the technician divides the uterus into 4 areas. The largest fluid pocket in each area is measured, and then these 4 numbers are added make up the AFI. An AFI value of 5 cm or less is considered oligohydramnios. With the single deepest pocket method, the technician looks for the largest pocket of amniotic fluid in the uterus. If the largest pocket is less than 2 cm by 1 cm, then that is considered a diagnosis of oligohydramnios (Nabhan and Abdelmoula 2009).

It is important to understand that amniotic fluid levels exist on a continuum and that there is no agreement among researchers about the cut-off value that predicts poor outcomes—the AFI level of 5 was arbitrarily chosen to define oligohydramnios (Nabhan and Abdelmoula 2009). Furthermore, a large body of research has shown that both AFI and single deepest pocket are poor predictors of true amniotic fluid volume. For example, the AFI catches only 10% of all cases of true oligohydramnios (10% sensitivity)(Gilbert 2012).

There are several factors that make it difficult to get an accurate ultrasound measurement. As fluid levels decrease, ultrasound results become less accurate. Inexperience on the part of the technician can reduce the accuracy of the test results, as well as the amount of pressure that the technician puts on the ultrasound probe. The position of the baby can also affect the accuracy of the results. (Nabhan and Abdelmoula 2009; Gilbert 2012).

So which is the best way to measure amniotic fluid?

In a Cochrane review, researchers combined the results from 5 randomized controlled trials with more than 3,200 women. In these studies, women were randomized to either the AFI method or the single deepest pocket method. Researchers found that when the AFI is used to measure amniotic fluid, women were 2.4 times more likely to be diagnosed with oligohydramnios, 1.9 times more likely to be induced, and 1.5 times more likely to have a Cesarean for fetal distress without any corresponding improvement in infant outcomes. The researchers concluded that the single deepest pocket measurement has fewer risks and should be the preferred way to measure amniotic fluid (Nabhan and Abdelmoula 2009).

What is the clinical significance of low amniotic fluid when a mother reaches 37 or more weeks?

In 2009, 91% of physicians believed that isolated oligohydramnios, or low amniotic fluid in an otherwise healthy pregnancy at term, was a risk factor for poor outcomes (Schwartz, Sweeting et al. 2009).

In the U.S., 91% of maternal-fetal physicians believe that isolated oligohydramnios at term is a risk factor for poor outcomes, and 95% will recommend labor induction.
Image Source robenjoyce

However, this belief is not accurate. In early studies on amniotic fluid and outcomes, researchers included babies with congenital defects , women with pre-eclampsia or intrauterine growth restriction (IUGR), and women who were post-term (past 42 weeks) in their samples. These women and babies are more likely to have low amniotic fluid, and they are also much more likely to have poor outcomes. So although early researchers found that babies born to women with low amniotic fluid had higher perinatal mortality rates (Chamberlain, Manning et al. 1984), higher Cesarean rates for fetal distress, and lower Apgar scores (Chauhan, Sanderson et al. 1999), the poor outcomes were due to the complications—not the low amniotic fluid (Gilbert 2012).

So, if a woman has TRUE ISOLATED oligohydramnios at term, meaning low amniotic fluid in a healthy pregnancy with a healthy baby at term (between 37 and 42 weeks), what are the risks?

There is no evidence that isolated oligohydramnios at term is a risk factor for poor outcomes. However, induction for isolated oligohydramnios leads to higher Cesarean rates. In a systematic literature review, I found 5 studies from the last 10 years. I will discuss the 3 highest quality studies here. For results from all 5, you can see my findings summarized in this Google document table here.

  1. Locatelli et al. (2003) studied 3,049 healthy pregnant women who were between 40 and 41.6 weeks pregnant. The purpose of this study was to find out if low amniotic fluid (defined as AFI ≤ 5) led to poor outcomes. Eleven percent of women had low amniotic fluid, and these women had higher induction rates (83% vs. 25%), higher Cesarean rates (15% vs. 11%), and higher Cesarean rates for non-reassuring fetal heart rates (8% vs. 4%). Babies born to women with low amniotic fluid were more likely to have birth weights beneath the 10th percentile (13% vs. 6%). There were no differences between groups with meconium staining, meconium aspiration, umbilical artery pH <7, or Apgar scores. There was only one stillbirth (in the normal fluid group) for a true knot in the umbilical cord.

After controlling for the fact that some women were induced and some women were having their first baby, the researchers found no association between Cesarean for non-reassuring heart rate and amniotic fluid. This means that the inductions were probably responsible for the higher Cesarean rates in the low amniotic fluid group. However, when the researchers controlled for gestational age, they found that the association between low birth weight and low amniotic fluid remained significant. This means that women with low amniotic fluid were 2 times more likely to have a baby that is born beneath the 10th percentile. These babies may have had undiagnosed fetal growth restriction (IUGR), which is a separate risk factor for poor outcomes.

  1. Manzaneres et al. (2006) compared outcomes from 206 healthy pregnant women who were induced for isolated oligohydramnios at term and 206 healthy pregnant women with normal amniotic fluid levels who went into spontaneous labor.  The women in both groups delivered between 37 and 42 weeks. The researchers found that the low amniotic fluid group was more likely to require forceps or vacuum delivery (26% vs. 17%), Cesarean delivery (16% vs. 6%), and have non-reassuring fetal status during labor (8% vs. 2%). The non-reassuring fetal status may have been due to the induction medications, but this explanation was not proposed by the authors. There were no differences between groups with birth weight, Apgar scores, meconium staining, neonatal admissions, or umbilical cord pH. In summary, the authors found that inducing labor for isolated oligohydramnios at term increased Cesarean and operative vaginal delivery rates without any improvement in newborn outcomes.
  1. There was one small pilot study done in which researchers randomized women with isolated oligohydramnios at term to induction or watchful waiting. The researchers randomly assigned 54 women who were 41 weeks pregnant to either induction or watchful waiting. There were no differences between groups in any outcomes, including birth weight, Cesarean delivery, Apgar scores, or neonatal admission. This study was limited by its small sample size and the fact that it only included women who were 41 weeks pregnant (Ek, Andersson et al. 2005).

So what is the evidence for induction because of low amniotic fluid (without any other complications) at term?

There is no evidence that inducing labor for isolated oligohydramnios at term has any beneficial impact on mother or infant outcomes. Based on the lack of evidence, any recommendation for induction for isolated oligohydramnios at term would be a weak recommendation based on clinical opinion alone.

In summary, this is what I found about low amniotic fluid in an uncomplicated pregnancy at term (37-42 weeks):

  • Ultrasound measurement is a poor predictor of actual amniotic fluid volume
  • The single deepest pocket method of measurement has fewer risks than the AFI
  • Poor outcomes seen with low amniotic fluid are usually due to underlying complications such as pre-eclampsia, birth defects, or fetal growth restriction
  • The main risk of low amniotic fluid at term in a healthy pregnancy is induction (and Cesarean delivery as a result of the induction) and potentially the risk of lower birth weight
  • Current evidence does not support induction for isolated oligohydramnios at term

Are women in your local areas being induced for isolated oligohydramnios at term? Are consumers and clinicians aware of this evidence? What is the standard of practice for evaluating amniotic fluid in your local facilities, AFI or Single Deepest Pocket? How do you discuss this in your classes and with your patients, clients and students?

References

  1. Beloosesky, R. and M. G. Ross. (2012). “Oligohydramnios.”   Retrieved 8/20/12, 2012, from www.UpToDate.com
  2. Brace, R. A. (1997). “Physiology of amniotic fluid volume regulation.” Clin Obstet Gynecol 40(2): 280-289.
  3. Chamberlain, P. F., F. A. Manning, et al. (1984). “Ultrasound evaluation of amniotic fluid volume. I. The relationship of marginal and decreased amniotic fluid volumes to perinatal outcome.” Am J Obstet Gynecol 150(3): 245-249.
  4. Chauhan, S. P., M. Sanderson, et al. (1999). “Perinatal outcome and amniotic fluid index in the antepartum and intrapartum periods: A meta-analysis.” Am J Obstet Gynecol 181(6): 1473-1478.
  5. Ek, S., A. Andersson, et al. (2005). “Oligohydramnios in uncomplicated pregnancies beyond 40 completed weeks. A prospective, randomised, pilot study on maternal and neonatal outcomes.” Fetal Diagn Ther 20(3): 182-185.
  6. Feldman, I., M. Friger, et al. (2009). “Is oligohydramnios more common during the summer season?” Arch Gynecol Obstet 280(1): 3-6.
  7. Gilbert, W. M. (2012). Amniotic Fluid Disorders. Obstetrics: Normal and Problem Pregnancies. S. G. Gabbe. Philadelphia, PA, Elsevier. 6.
  8. Locatelli, A., P. Vergani, et al. (2004). “Perinatal outcome associated with oligohydramnios in uncomplicated term pregnancies.” Arch Gynecol Obstet 269(2): 130-133.
  9. Nabhan, A. F. and Y. A. Abdelmoula (2009). “Amniotic fluid index versus single deepest vertical pocket: a meta-analysis of randomized controlled trials.” International journal of gynaecology and obstetrics: the official organ of the International Federation of Gynaecology and Obstetrics 104(3): 184-188.
  10. Patrelli, T. S., S. Gizzo, et al. (2012). “Maternal hydration therapy improves the quantity of amniotic fluid and the pregnancy outcome in third-trimester isolated oligohydramnios: a controlled randomized institutional trial.” J Ultrasound Med 31(2): 239-244.
  11. Schwartz, N., R. Sweeting, et al. (2009). “Practice patterns in the management of isolated oligohydramnios: a survey of perinatologists.” J Matern Fetal Neonatal Med 22(4): 357-361.
  12. Stigter, R. H., E. J. Mulder, et al. (2011). “Fetal urine production in late pregnancy.” ISRN Obstet Gynecol 2011: 345431.
  13. Ulker, K., I. Temur, et al. (2012). “Effects of maternal left lateral position and rest on amniotic fluid index: a prospective clinical study.” J Reprod Med 57(5-6): 270-276.
About Rebecca Dekker
Rebecca Dekker, PhD, RN, APRN, is an Assistant Professor of Nursing at a research-intensive university and author of www.evidencebasedbirth.com. Rebecca’s vision is to promote evidence-based birth practices among consumers and clinicians worldwide. She publishes summaries of birth evidence using a Question and Answer style.

 

 

 

Evidence Based Medicine, Fetal Monitoring, Guest Posts, Healthy Birth Practices, Healthy Care Practices, informed Consent, Maternity Care, Medical Interventions, Systematic Review, Uncategorized , , , , , , , , ,

Science And Sensibility; Words To Live By

May 14th, 2012 by avatar

Science is simply common sense at its best.  ~Thomas Huxley

Science.  Sensibility.  Science and sensibility are good words.  I gravitate to these words naturally.  These words offer me security, comfort and a feeling of order in the world.  I am delighted and honored to be the new Community Manager for Lamaze International’s Science and Sensibility blog and every time I think of the name of the blog I smile, because it feels like coming home.  It defines what I think is important in the work that I do as a childbirth educator and doula.

Science and sensibility is the crux of why I became a Lamaze certified childbirth educator.  The foundation of Lamaze and the principles that guide the work of this blog and of the entire Lamaze organization are built on quality research.  I am proud when I teach The Six Lamaze Healthy Birth Practices in my own classes and I can share the citations that support each practice.  This is the kind of information that should guide informed decision-making by the families that we work with and research that should guide protocols and practice by the health care providers who families trust to care for them during the childbearing year.

I just finished teaching a three day Passion for Birth childbirth educator workshop working with men and women who are on the path to becoming Lamaze certified childbirth educators.  During the workshop, we dedicate time to discuss research.  What makes a good study?  What are reliable sources for information?  How to understand the research?  Vocabulary words like “peer reviewed” and “randomized controlled trial” and other terms are discussed.  We want new educators to feel comfortable looking at research, understanding research and being able to apply current information in their classes as they work with new families.  The workshop attendees often state that they are intimidated, scared and confused about interpreting a research study.  They are not sure how to jump in or what to look for.  Here’s where this blog, Science and Sensibility, can really shine!  Science and Sensibility can help take the mystery out of reading the current research and help new educators, experienced educators, other professionals and interested parents to feel confident about understanding articles and research that impacts new families.

 The purpose of this blog, since it’s inception, has been to highlight current research on pregnancy, maternity care, birth, parenting and breastfeeding topics.  To share important studies, to break them down, provide a common-sense approach to the material, which is often covered in rather technical terms.  And this…this, is what really makes me feel good.  This mission is what makes me absolutely thrilled to be in the role of Community Manager.  To follow in the footsteps of the previous Community Managers, Amy Romano and Kimmelin Hull, who have worked hard to bring you the research, to highlight important studies and to demonstrate how Lamaze supports and incorporates this information and makes it available to educators, parents and the community at large in the work that it does as a leader in the childbirth education arena promoting normal birth.

My goals for this blog are to:

  • Continue to profile current research.
  • Present research in a matter of fact way with resources for when you want more information.
  • Bring you guest bloggers who are experts in their field, inviting them to share their expertise.
  • Reach out to the investigators themselves, in order to get the inside scoop on the research.
  • Help you to learn more about the leaders and organizations that are on the front lines of improving care for mothers and their babies.
  • Recognize that issues of pregnancy, birth and parenting are global in nature.
  • Follow the science and make it understandable and relevant to you.
  • Do all of this in entertaining, enjoyable ways.

I invite you to participate with me on this journey. I call on you to share your thoughts, ask your questions, and suggest topics to be explored.  Consider contributing your own ideas by becoming a guest blogger. Let me know who you want to hear from and what you want to know more about.  This blog belongs to all of us and requires the participation of many to make it as rich and successful as it has been and can continue to be.  I am excited about the possibilities and opportunities that await me and all of us.  Together, we can be sure that the science is understandable and that future educators embrace the opportunity to comprehend important research, discuss with others and share with families.

Let’s begin!

 

 

 

Childbirth Education, Evidence Based Medicine, Healthy Birth Practices, informed Consent, Maternity Care, Practice Guidelines, Research, Science & Sensibility, Systematic Review , , , , , , , ,