Membrane sweeping and GBS: A litigious combination?
Although it led to a defense verdict, a recent lawsuit suggests sweeping in a colonized patient can expose you to litigation
The perinatologist said his opinion was based on the statements of the infectious disease specialist, who in turn cited a poster presentation at the Infectious Diseases Society for Obstetrics and Gynecology meeting in 20017—which occurred a year after the neonatal death. The poster presentation was a series of 8 cases of perinatal sepsis following membrane stripping; the cases occurred between 1993 and 2000 and were provided by a parents’ group with affected children, “The Jesse Cause.”
Only the perinatologist appeared at trial. When asked to identify a single piece of published, peer-reviewed literature documenting an increased risk of neonatal GBS with membrane stripping, he was unable to do so.
Defense
An expert testified that, although GBS colonization occurs in 20% of all pregnancies, there are no data—prospective, retrospective, or controlled—to suggest that membrane sweeping in GBS-positive patients is associated with GBS sepsis of the newborn, and that membrane sweeping was appropriate in a woman with a fetus affected by unexplained IUGR.
The jury returned a defense verdict after less than 1 day of deliberation. It was not appealed.
As this case demonstrates, expert witnesses sometimes testify on a plaintiff’s behalf despite clear data refuting their statements. ObGyns should be aware that even a practice with a long history, such as membrane stripping, may be proclaimed outside the standard of care by such witnesses. We consider this kind of testimony unethical.
Until we have more data confirming or refuting the association between membrane sweeping (in cases of GBS colonization) and neonatal sepsis, or the medicolegal system changes, obstetricians should proceed with caution. We counsel our patients thoroughly and document the discussion.
Suneet P. Chauhan, MD, Director of Maternal–Fetal Medicine Aurora Women’s Pavilion, Perinatal Assessment Center, West Allis, Wisc
Lower risk of postterm pregnancy
de Miranda E, van der Bom JG, Bonsel GJ, Bleker OP, Rosendaal FR. Membrane sweeping and prevention of post-term pregnancy in low-risk pregnancies: a randomized controlled trial. BJOG. APRIL 2006;113:402–408.
The conclusion of this herculean randomized controlled trial is unequivocal: Sweeping the membranes at 41 weeks’ gestation, regardless of parity, significantly reduces the likelihood a pregnancy will reach 42 weeks. Number needed to treat: 6.
Risks of postterm pregnancy are numerous: greater likelihood of longer labor, cesarean section or operative vaginal delivery, infection, postpartum hemorrhage, shoulder dystocia, stillbirth or neonatal death, and meconium aspiration, to name a few. So any strategy to prevent it—particularly one that is easy and inexpensive—is welcome. The only adverse effect of membrane sweeping is increased bleeding; otherwise, the rates of peripartum complications are similar in women with or without the intervention.
Until 2006, studies of membrane sweeping were not randomized. Empiric evidence has suggested that membrane sweeping is ineffective. As a result, many clinicians eschewed the practice. According to the American College of Obstetricians and Gynecologists (ACOG) practice bulletin on postterm pregnancy,8 management options at 41 weeks’ gestation are limited to labor induction or expectant management with antepartum surveillance.
The de Miranda study was conducted at 51 primary care midwifery practices in the Netherlands.
Strengths. In addition to the randomized, controlled design, the trial’s strengths are:
- Subanalysis of the data based on parity, on whether the gestational age was determined by ultrasound before 18 weeks, and whether the Bishop score was below 6 or at 6 or above
- Participation by several midwives reflected real clinical practice
In addition, almost 90% of patients who underwent the intervention said they would choose it again in the next pregnancy.
Weaknesses. The de Miranda study does have weaknesses:
- Patients randomized to the control group did not undergo a vaginal examination to determine whether they had a cervix favorable for labor induction. This omission seems unacceptable and contrary to ACOG recommendations.8
- The perinatal mortality rate (for all women in the study) was 5.4 per 1,000 births, which is higher than the 1.0 to 3.1 per 1,000 quoted in the ACOG practice bulletin.
There also is some question of which management strategy women prefer, because an earlier study by the Canadian Multicenter Postterm Pregnancy Trial Group9 reported that women assigned to induction were significantly more satisfied than those allocated to observation.
Tan PC, Jacob R, Omar SZ. Membrane sweeping at initiation of formal labor induction. A randomized controlled trial. Obstet Gynecol. MARCH 2006;107:569–577.
The Tan trial randomized 274 women scheduled for induction at term to membrane sweeping or no membrane sweeping at the initiation of induction. Although roughly 1 in 5 deliveries are induced, induction leads to spontaneous vaginal delivery much less often than does spontaneous labor. The Tan study sought to determine whether membrane sweeping increases the likelihood of spontaneous vaginal delivery. Swept women had:
- Higher spontaneous vaginal delivery rate (69% vs 56%, P=.041)
- Shorter induction-to-delivery interval (mean 14 vs 19 hours, P=.003)
- Fewer requirements for oxytocin (46% vs 59%, P=.037)
- Shorter duration of oxytocin infuson (mean 2.6 vs 4.3 hours, P=.001)
- Greater satisfaction with the birth process
Recommendations
These trials are sufficient reason to undertake membrane sweeping every 48 hours in women who strongly desire expectant management at 41 weeks’ gestation
Counsel patients about the risks of observation
Test fetal well-being twice weekly
Sweeping may ease labor induction
