Science & Sensibility

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Regular contributor Deena Blumenfeld shares her recent experience with a “research” article that washed over social media outlets and was shared and discussed by many birth professionals.  Deena explains how she fell in step with others and ended up being lead down the wrong path.  Have you every made this mistake too?  Please share your thoughts in our comment section.- Sharon Muza, Science & Sensibility Community Manager.

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Gathering information from social media can be like playing a giant game of “telephone” with a million of your closest friends.

This is often how it goes:

• Someone reads an article. They post to Facebook (or other venue) a link and a comment.
• We read this person’s comment and add our own comment.
• Then we go back and skim the article, and comment again.
• Next we post a link to the article, with our own comments and opinions regarding the article.
• The next reader takes our opinion as gospel, only reads the headline of the article and then shares our opinion on their page, neglecting to link the article with their comment.
• So now we have a rumor about an opinion and after 345 more postings, no one knows where the original source was of what anyone is talking about anymore.  But, whatever it is, it sounds AWFUL and we are indignant about it.

Does this sound familiar to you? Have you ever taken a rumor, opinion or comment about an article or study to be gospel truth, without fully reading and researching the information on your own… and then go on to repeat that rumor or opinion? 

I’ll sheepishly raise my hand here…

Not too long ago, there was an article on medpagetoday.com entitled “New Form of Misoprostol Speeds Up Labor.” Now, without reading the article, doesn’t it seem that we now have a form of misoprostol being used for augmentation? 

This is the misinterpretation that was flying around Facebook, Twitter and other social media sites for days after the article was published on February 18, 2013. The outrage, fear and condemnation of anyone who thought it might possibly be a good idea to use misoprostol for augmentation was overwhelming. I read, and participated in, many discussions regarding the dangers of this drug; uterine rupture, mothers who have died, babies who have died, the Safe Motherhood Quilt Project, and so on. 

But yet we all missed it, me included.  That misleading headline leads us to believe that this was misoprostol for augmentation of labor; when in reality, it is an article about a new form of misoprostol, designed in the appropriate dosage, to induce labor.  This ‘little oops’ caused a big stir for not much. 

So, let’s look at what the article really talks about and what we should know.

• This is an article about an abstract which was presented at a conference. It is not a peer-reviewed, published study.
• We do not have access to the full study, since it isn’t published. So, we cannot evaluate it effectively.
• The study compared the efficacy of this new form of misoprostol suppository to the existing dinoprostone (cervadil) suppository for induction of labor.
• This study of 1,358 women found that the misoprostol suppository worked more quickly than the dinoprostone to get women to active labor as well as to birth.

“Along with the primary efficacy benefit of shorter time to vaginal delivery, the novel agent was also associated with faster delivery of any type, vaginal or cesarean (median 18.3 hours versus 27.3 hours with dinoprostone, P<0.001).”

“Other secondary outcome benefits were shorter time to active labor at 12.1 hours versus 18.6 hours, respectively (P<0.001), with substantially fewer women needing oxytocin prior to delivery (48% versus 74%, P<0.001).” 

Hang on a minute: “faster delivery of any type, vaginal or cesarean.” If the results of the induction end up as a cesarean, can we call it a successful induction? I’m not sure we can. I think this is a failed induction. Sure the medication worked to get labor started, but for whatever reason she ended up with a cesarean section. Faster to a cesarean section – wouldn’t it have been even faster to just schedule the cesarean section? 

“T’he primary safety outcome of cesarean delivery came out similar between groups at 26% with misoprostol and 27% with dinoprostone (P=0.65). Nor was there a difference in indication for cesarean section.”

When asked at the session why a faster vaginal delivery didn’t translate into fewer cesarean deliveries, Wing pointed to the myriad other factors that play into delivery mode. “We can flip the switch on but that doesn’t always get us the desired result,” she told the audience.” 

The article is leaning towards “faster is better” in terms of labor. We are left with more questions than answers. The answers may be found within the study itself, however, we don’t have access to the study. My questions:

But why? Why is a faster induction (or faster labor) better than a slower one?

Aren’t faster labors more painful? Aren’t contractions more challenging to cope with when they are more intense?

Do we have high rates of fetal distress with a faster labor vs. a slower one?

Who benefits from a faster birth?

The articles states that fewer women needed to be augmented with pitocin with a misoprostol induction vs. a dinoprostone induction. Is that a good thing? Bad? Neutral?

We also don’t know the researcher’s intentions. Without being able to read the study, we can only make assumptions. Do we assume the intention is a faster labor? Do we assume the intention is to make misoprostol safer for induction? Something else? Or maybe, just maybe, we don’t assume anything at all. Assumptions can be very dangerous and in most cases, they are wrong. 

My Take Away

The take away from all of this is that an article about an abstract presented at a conference leaves us with more questions than answers. We cannot accurately evaluate that which we cannot read in its entirety. Social media is a good tool, but we should be cautious about that which sounds too good (or bad!) to be true. We should take others opinions as just that – opinions, until we’ve done our own solid research. We should also be cautious about the ‘click and share’ phenomenon. Double check, do your homework and make sure the information we share is accurate. I’ll do better next time too.

For more on misoprostol for labor induction please read:

1. Science & Sensibility: Update on Spin Doctoring Misoprostol (Cytotec): Unsafe at Any Dose
2. Science & Sensibility: ACOG’s 2009 Induction Guidelines: Spin Doctoring Misoprostol (Cytotec)
3. Journal of Perinatal Education: The Freedom to Birth—The Use of Cytotec to Induce Labor: A Non-Evidence-Based Intervention by Madeline Oden
4. WHO: Misoprostol for cervical ripening and induction of labour
5. WHO: WHO Recommendations for Induction of Labor, 2011
6. Induced and Seduced: The Dangers of Cytotec by Ina May Gaskin
7. Adverse Events Following Misoprostol Induction of Labor by Marsden Wagner, MD, MS

Deena Blumenfeld Cesarean Birth, Childbirth Education, Evidence Based Medicine, Guest Posts, Maternity Care, Medical Interventions, New Research, Research, Uncategorized cytotec, Deena Blumenfeld, guest post, guest posts, induction, labor induction, misoprostol, power of social media, research, Social Media

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Last April, the ABIM Foundation, with Consumer Reports and other partners, drew national attention to overuse of ineffective and harmful practices across the health care system with their Choosing Wisely campaign. As part of the campaign, professional medical societies identified practices within their own specialties that patients should avoid or question carefully. Today, the American College of Obstetricians and Gynecologists (ACOG) and the American Academy of Family Physicians (AAFP) have joined the campaign, drawing national attention to the overuse and misuse of induction of labor. ACOG and AAFP are telling women and their maternity care providers:

• Don’t schedule elective, non-medically indicated inductions of labor or cesarean deliveries before 39 weeks 0 days gestational age.

• Don’t schedule elective, non-medically indicated inductions of labor between 39 weeks 0 days and 41 weeks 0 days unless the cervix is deemed favorable. 

(“Favorable” means the cervix is already thinned out and beginning to dilate, and the baby is settling into the pelvis. Another word for this is “ripe,” and doctors and midwives use a tool called the Bishop Score to give an objective measurement of ripeness. Although ACOG and AAFP do not define “favorable,” studies show cesarean risk is elevated with a Bishop Score of 8 or lower in a woman having her first birth and 6 or lower in women who have already given birth vaginally.)  

Much work has already been done to spread the first message. Although ACOG has long advised against early elective deliveries, a confluence of quality improvement programs and public awareness campaigns have made it increasingly difficult for providers to perform non-medically indicated inductions or c-sections before 39 weeks.

But as the public and the health care community have accepted the “39 weeks” directive, concern about unintended consequences has grown. Christine Morton, a researcher at the California Maternal Quality Care Collaborative and regular contributor to Science & Sensibility, sums up concerns shared by many, including Childbirth Connection:

It is possible that this measure may sensitize stakeholders to the wrong issue: timing of birth rather than the fact that it is generally best when labor begins on its own.  Additionally, is it possible that 39 weeks could become the new “ideal” gestational age, because it will be assumed that 39 completed weeks is the best time to be born?

The second Choosing Wisely statement aims to mitigate these unintended consequences. Inducing with an unripe cervix significantly increases the chance of a c-section and its many associated harms. Women considering induction for a non-medical reason deserve to know about these excess risks, and should question whether it is worth any non-medical benefits of elective delivery they perceive or expect. Lamaze International has spoken to the importance of letting labor begin on its own, as it is the first topic in the Six Healthy Birth Practices.

But will the new message lead women and care providers to think that delivery is indicated once a woman’s cervix is ripe? Through the Choosing Wisely campaign ACOG and AAFP have made powerful statements acknowledging that scheduled delivery is unwise if the baby or the woman might not be ready for birth. Although gestational age and the Bishop score are tools to estimate readiness for birth, the best indicator of readiness is still the spontaneous onset of labor at term, the culmination of an intricate interplay of hormonal signals between the fetus and the woman. Anytime we intervene with the timing of birth we have to weigh the potential benefits and harms of overriding that process in the context of the fully informed preferences and values of women.

This summer, our collaboration with the Informed Medical Decisions Foundation will culminate in the release of our first three Smart Decision Guides. These evidence-based, interactive decision support tools will help women learn the possible benefits and harms of scheduled delivery versus waiting for labor to start on its own and to weigh these based on what is most important to them. These tools help women choose wisely – to identify when an option is not appropriate or safe for them, and to thoughtfully weigh options when there are both pros and cons to consider.

Interested in learning more about shared decision making in maternity care? Sign up for a free webinar on March 13 sponsored by the Informed Medical Decisions Foundation to hear more about what clinicians, consumers, employers, and others thinking about the importance of maternity care shared decision making.

Amy Romano ACOG, Childbirth Education, Evidence Based Medicine, Guest Posts, Healthcare Reform, Healthy Birth Practices, Healthy Care Practices, informed Consent, Maternal Quality Improvement, Medical Interventions, Practice Guidelines, Pre-term Birth, Webinars AAFP, ABIM Foundation, ACOG, Amy Romano, avoiding labor induction, Childbirth Connection, Foundation for Informed Medical Decision Making, induction, informed Consent, labor induction, Webinars

The  Canadian Medical Association Journal, published in their September 12, 2012 issue a very interesting study examining how a team approach to maternity care might improve maternal and neonat aloutcomes.  The study, Effect of a collaborative interdisciplinary maternity care program on perinatal outcomes  is reviewed here.

The Challenge

Photo Source: http://www.flickr.com/photos/jstownsley/28337593/

The number of physicians in Canada who provide obstetric care has declined in past years for reasons that include increasing physician retirement, closure of rural hospitals, liability concerns, dissatisfaction with the lifestyle and a difficulty in accessing maternity care in a variety of settings.  While registered midwife attended births may be on the rise, midwives in Canada attend less than 10% of all births nationwide.   At the same time as the number of doctors willing or able to attend births decline, cesarean rates are on the rise,  causing pressure on the maternity care system, including longer hospital stays both intrapartum and postpartum, which brings with it the associated costs and resources needed to accommodate this increase.

The diversity of the population having babies in many provinces is increasing, presenting additional challenges in meeting the non-French/English speaking population, who are more at risk for increased obstetrical interventions and are less likely to breastfeed.

The Study

In response to these challenges, the South Community Birth Program was established to provide care from a consortium of providers, including family practice physicians, community health nurses, doulas, midwives and others, who would work together to serve the multiethnic, low income communities that may be most at risk for interventions and surgery.

The retrospective cohort study examined outcomes between two matched groups of healthy women receiving maternity care in an ethically diverse region of South Vancouver, BC, Canada that has upwards of 45% immigrant families, 18% of them arriving in Canada in the past 5 years.  One group participated in the South Community Birth Program and the other received standard care in community based practices.

The South Community Birth Program offers maternity care in a team-based shared-care model, with the family practice doctors, midwives, nurses and doulas working together .  Women could be referred to the program by the health care provider or self refer.  After a few initial standard obstetrical appointments with a family practice doctor or midwife occur to determine medical history, physical examination, genetic history, necessary labs and other prenatal testing, the women and their partners are invited to join group prenatal care, based on the Centering Pregnancy Model.  Approximately 20% of the first time mothers choose to remain in the traditional obstetric care model.  10-12  families are grouped by their expected due date, and meet for 10 scheduled sessions, facilitated by either a family physician or midwife and a community nurse.  Each session has a carefully designed curriculum that covers nutrition, exercise, labor, birth and newborn care, among other topics.  Monthly meetings to discuss individual situations and access to comprehensive electronic medical records enhanced the collaboration between the team. Trained doulas, who speak 25 different languages, also meet with the family once prenatally and provide one on one continuous labor support during labor and birth. The admitting midwife or physician remains in the hospital during the patient’s labor and attends the birth.

After a hospital stay of 24-48 hours, the family receives a home visit from a family practice physician or midwife the day after discharge. Clinic breastfeeding and postpartum support is provided by a Master’s level clinical nurse specialist who is also a board certified lactation consultant.  At six weeks, the mother is discharged back to her physician, and a weekly drop in clinic is offered through 6 months postpartum.

The outcomes of the women in the South Community Birth Program were compared to women who received standard care from their midwives or family practice physicians.  Similar cohorts were established of women carrying a single baby of like ages, parity, and geographic region, and all the mothers were considered low risk and of normal body mass index.

The primary outcome measured was the proportion of women who underwent cesarean delivery.  The secondary outcomes measured were obstetrical interventions and maternal outcomes (method of fetal assessment during labor, use of analgesia during labor, augmentation or induction of labor, length of labor, perineal tramau, blood transfusion and length of stay) and neonatal outcomes (stillbirth, death before discharge, Apgar score less than 7, preterm delivery, small or large for gestational age, length of hospital stay, readmission, admission to neonatal intensive care unit for more than 24 hours and method of feeding at discharge).

Results

There was more incidence of diabetes and previous cesareans in the comparison group but the level of alcohol and substance use was the same in both groups.  Midwives delivered 41.9% of the babies in the birth program and 7.4% of babies in the comparison group.

When the rate of cesarean delivery was examined for both nullips and multips, the birth group women were at significantly reduced risk of cesarean delivery and were not at increased risk of assisted vaginal delivery with forceps or vacuum.

Interestingly, the birth program women who received care from an obstetrician were significantly more likely to have a cesarean than those receiving in the standard program who also received care from an obstetrician.  More women in the birth program with a prior cesarean delivery planned a vaginal birth in this pregnancy, though the proportion of successful vaginal births after cesareans dd not differ between the two groups.

The women in the community birth program experienced more intermittent auscultation vs electronic fetal monitoring and were more likely to use nitrous oxide and oxygen alone for pain relief and less likely to use epidural analgesia (Table 3).  Though indications for inductions did not differ, the birth program women were less likely to be induced.  More third degree perineal tears were observed in the birth program group but less episiotomies were performed.  Hospital stays were shorter for both mothers and newborns in the community program.

When you look at the newborns in the birth program, they were at marginally increased risk of being large for gestational age and were readmitted to the hospital in the first 28 days after birth at a higher rate, the majority of readmissions in the community and standard care group were due to jaundice. Exclusive breastfeeding in the birth program group was higher than in the standard group.

Discussion

The mothers and the babies in the community birth program were offered collaborative, multidisciplinary, community based care and this resulted in a lower cesarean rate, shorter hospital stays, experienced less interventions and they left the hospital more likely to be exclusively breastfeeding. Many of the outcomes observed in this study, especially for the families participating in the South Birth Community Program are in line with Lamaze International’s Healthy Birth Practices.  There are many questions that can be raised, and some of them are are discussed by the authors.

Was it the collaborative care from an interdisciplinary team result in better outcomes?  Was there a self-selection by the women themselves for the low intervention route that resulted in the observed differences?  Are the care providers themselves who are more likely to support normal birth self-selecting to work in the community birth program? Did the fact that the geographic area of the study had been underserved by maternity providers before the study play a role in the outcomes? Did the emotional and social support provided by the prenatal and postpartum group meetings facilitate a more informed or engaged group of families?

I also wonder how childbirth educators, added to such a model program, might also offer opportunity to reduce interventions and improve outcomes  Could childbirth educators in your community partner with other maternity care providers to work collaboratively to meet the perinatal needs of expectant families?  Would bringing health care providers interested in supporting physiologic birth in to share their knowledge in YOUR classrooms help to create an environment where families felt supported by an entire skilled team of people helping them to achieve better outcomes.

Would this model be financially and logistically replicable in other underserved communities and help to alleviate some of the concerns of a reduction in obstetrical providers and increased cesareans and interventions without improved maternal and newborn outcomes? And how can you, the childbirth educator, play a role?

References

Azad MB, Korzyrkyj AL. Perinatal programming of asthma: the role of the gut microbiota. Clin Dev Immunol 2012 Nov. 3 [Epub ahead of print].

Canadian Association of Midwives. Annual report 2011. Montréal (QC): The Association; 2011. Available: www .canadianmidwives.org /data/document /agm %202011 %20inal .pdf

Farine D, Gagnon R; Maternal Fetal Medicine Committee of the Society of Obstetricians and Gynaecologists of Canada. Are we facing a crisis in maternal fetal medicine in Canada? J Obstet Gynaecol Can 2008;30:598-9.

Getahun D, Oyelese Y, Hamisu M, et al. Previous cesarean delivery and risks of placenta previa and placental abruption.Obstet Gynecol 2006;107:771-8.

Giving birth in Canada: the costs. Ottawa (ON): Canadian Institute of Health Information; 2006.

Godwin M, Hodgetts G, Seguin R, et al. The Ontario Family Medicine Residents Cohort Study: factors affecting residents’ decisions to practise obstetrics. CMAJ 2002;166:179-84.

Hannah ME. Planned elective cesarean section: A reasonable choice for some women? CMAJ 2004;170:813-4.

Harris, S., Janssen, P., Saxell, L., Carty, E., MacRae, G., & Petersen, K. (2012). Effect of a collaborative interdisciplinary maternity care program on perinatal outcomes. Canadian Medical Association Journal, doi: DOI:10.1503 /cmaj.111753

Ontario Maternity Care Expert Panel. Maternity care in Ontario 2006: emerging crisis, emerging solutions: Ottawa (ON): Ontario Women’s Health Council, Ministry of Health and LongTerm Care; 2006.

Reid AJ, Carroll JC. Choosing to practise obstetrics. What factors influence family practice residents? Can Fam Physician 1991; 37:1859-67.

Sharon Muza Babies, Breastfeeding, Cesarean Birth, Childbirth Education, Evidence Based Medicine, Fetal Monitoring, Healthy Birth Practices, Healthy Care Practices, Maternity Care, Medical Interventions, Midwifery, New Research, Research, Uncategorized breastfeeding, Canada, cesarean, Childbirth Education, epidurals, Healthy Birth Practices, hospitals, induction, interventions, maternity care quality, maternity care systems, MD, midwives, newborns, Sharon Muza, South Community Birth Program

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

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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 10^th 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 10^th 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.

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. You can contact Rebecca via email here.

Sharon Muza Evidence Based Medicine, Fetal Monitoring, Guest Posts, Healthy Birth Practices, Healthy Care Practices, informed Consent, Maternity Care, Medical Interventions, Systematic Review, Uncategorized AFI, Evidence Based Birth, Evidence Based Medicine, Fetal Monitoring, guest post, Healthy Birth Practices, induction, Oligohydramnios, prenatal ultrasound, Rebecca Dekker

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

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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.

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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.

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