Wednesday, July 06, 2016

Three Perspectives on External Cephalic Version

First Amsterdam Breech Conference, Day 1
Three Perspectives on External Cephalic Version (ECV)

Marjolein Kok
Turn That Breech!: Important Aspects Of ECV

An obstetrician at the Academic Medical Center in Amsterdam, Marjolein Kok MD, PhD noted that in the Netherlands, there are about 6,000 breech babies born per year, of which 4,800 are born via cesarean and 1,200 vaginally. In the US, fetal malpresentation is the third most common reason for cesarean section. Her goal is to prevent all breech deliveries by turning the babies beforehand. However, she noted that this might be an impossible goal, as ECV has a 40-60% success rate. Still, ECV significantly lowers the overall cesarean rate for breech presentation by almost half. Of utmost importance for a successful ECV are an experienced operator and tocolysis.

She presented a list of favorable conditions for ECV, with the most important on top. A relaxed uterus is by far the most favorable factor, followed by an unengaged breech and a palpable head.

The rest of her presentation overviewed the literature on ECV from several angles:

Safety:  A 2008 meta-analysis by Grootscholten et al (PDF here) found that serious complications occur in less than 1% of ECV.

Eligibility: There is very little consensus on contraindications for ECV. In the five national guidelines surveyed in the above meta-analysis, there were 18 total contraindications, but only one was shared between all five guidelines: oligohydramnios. In addition, no contraindications in the literature were evidence-based, thus leaving only level III evidence (expert opinion) to guide decision-making. Her own level III recommendations for contraindications are:
  • History of placental abruption
  • Signs of placental abruption in current pregnancy
  • Severe preeclampsia or HELLP syndrome
  • Signs of fetal distress

Timing: She presented evidence from a Canadian RCT comparing early and late ECV. The data points to late ECV  (after 36 weeks) as being preferable and more cost-effective than early ECV (34-36 weeks).

How? When Marjolein Kok performs ECV, she follows the following procedures:
  • CTG to determine fetal-wellbeing
  • Ultrasound to determine presentation
  • Examination
  • Ultrasound gel (she feels it helps the operator's hands glide smoothly)
  • 2 operators (I didn't write down her reason for having two people present)
  • Tocolysis
  • Head roll
  • Anti-D immunoglobulin for Rh- women

Results: Marjolein noted that women with successful ECVS are still at higher risk for cesarean section compared to women with spontaneous cephalic babies. One study by de Hundt et al (2014) found the rate to be twice as high. However, this is still an improvement over a 100% cesarean rate in places where vaginal breech birth is not offered.

Marjolein concluded that overall ECV is safe and effective. More women are eligible that one might think, and it should be offered to every eligible women. Unfortunately, it's still not as widely used as she'd hope, as noted in a study by Vlemmix et al (2010).

Question & Answer Session
Q: What is the evidence for doing CTG before or after ECV?
A: There’s no evidence for doing it, but I usually do it before to assess fetal condition. It’s debatable. After ECV, we know that about 6% of fetuses have abnormal CTGs (usually temporary).

Q: (OB from Sheffield) If breech is normal, why do we have to turn breech babies around? This is more of a rhetorical question since I do ECVs in my practice.
A: Many places in the world don’t offer vaginal breech birth, so this can help in places where that’s not an option.

Mary Sheridan
Evidence-Based Management Of ECV In the UK: Findings From The “Think Breech” study

Mary Sheridan RM, MSc, is the coordinator of the Think Breech project and is currently working on her PhD. She is also a Midwife/Lecturer at Guy’s and St. Thomas’ NHS Foundation Trust/King’s College London. In the UK, 16% of all cesareans are due to breech presentation, and there are between 25-30,000 breech babies per year. Her project aimed to see how well maternity units were following the 2010 guidelines (PDF here). She visited units where the evidence-based guidelines were well-implemented, determined what these units had in common, then brought those findings to a unit that needed to improve.

Only 31% of the units she surveyed kept adequate data about their maternity patients--one of many barriers to evidence-based managements. Other barriers included unit culture, poor communication systems, and competing priorities.

Joost Velzel
How To Improve the Effectiveness Of ECV

Joost Velzel is a MD/PhD candidate at Academic Medical Center in Amsterdam. He is interested in improving the effectiveness of ECV, with a special focus on which type of tocolysis is preferable. His primary aims are:

1. Clarify best practice for tocolysis
2. Newtork meta analysis
3. Routine implementation

As Marjolein Kok mentioned in her presentation, tocolysis is the most effective predictor of a successful ECV. But which kind works best? He summarized the 18 existing RCTs on tocolysis beginning in 1987. His own research group also conducted their own RCT on beta mimetics. (Rixa's note: I don't think either of these have been published yet; if anyone can update this information, please leave a comment!)

One problem with existing RCTs is that they compare only one or two types of tocolysis against a placebo. So perhaps A has been compared to B, and B to C. But A has never been compared with C, so how can you tell whether A is better than C?

A network meta-analysis permits researchers to compare treatment methods that have never been directly compared in individual studies. Joost noted that a NMA can be more conclusive and more refined and precise than single RCTs or non-networked meta-analyses. His research group's network meta-analysis on tocolysis (proposal from 2014) examined beta mimetics, calcium channel blockers, nitrates, and oxytocin receptor blockers, with placebos as the reference. They concluded that "beta mimetic is the only proven effective tocolytic agent."

Joost noted that tocolytics have common side effects, but most are transitory. Serious effects such as hypertension occur less than 2% of the time. Women are generally willing to take medication with side effects if increases the success rate of ECV.

He noted that in the Netherlands, midwives are not allowed to administer tocolysis directly; they must have a physician administer the tocolysis even if they are the one doing the ECV. His main goal is to reduce breech presentation at turn and to optimize fetal version.

Question & Answer Session
Q: Do you know anything about tocolysis for ECVs done in a home setting? I don't think it's been studied yet.
A: Yes, that would be a great topic for a RCT. We don’t have information on that yet.

Q: (OB from Los Angeles) My real goal is to help women achieve a vaginal birth. In Los Angeles, if ECV is unsuccessful, almost all women have a cesarean delivery. The success of ECV is very tightly linked to cesarean section. Did women in these studies have the option of a vaginal breech birth if the ECV was unsuccessful?
A: Yes, I think that vaginal breech birth was an option in these studies, but I am not sure.

Q: Was the context of the mother taken into account?
A: No—that's something for the next round of studies!

Q: What beta mimetic agent? Which route? How long did you wait before doing the ECV?
A: For my RCT we used atosiban (rather than fenoterol) intravenously. We waited 15 minutes before doing the ECV.

Q: (Obstetrician who does home births). I almost always use hypnosis for ECV. I have a medical hypnotherapist for the procedure. I would suggests this as a future object of study.
A: Yes—another RCT idea!
A from audience: There’s a paper on it in the literature—it’s published.

Rixa's note: I was able to find two papers on the topic. Note that the first one was co-authored with Anke Reitter and Frank Louwen:

Q: When ECV doesn’t work, could it be more due to the resistance of the abdominal muscles than the uterus?
A: Perhaps, I don’t know. div>


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