Conference Coverage

Don’t push women into preterm delivery after myomectomy



Vaginal trial of labor is safe after myomectomy, at least if the uterine cavity wasn’t entered, according to investigators from Northwestern University, Chicago.

Dr. Nathan King of Northwestern University, Chicago M. Alexander Otto/MDedge News

Dr. Nathan King

The American College of Obstetricians and Gynecologists lists prior myomectomy as a medically-indicated reason for delivery before 39 weeks. The advice reflects a traditional concern that uterine scars will rupture during labor, with potentially devastating consequences for both mother and infant.

Reviews have put the risk at less than 1%, so ob.gyns. have shied away from ACOG’s blanket advice and now use uterine-cavity entry during myomectomy as their talisman for deciding whether or not to offer women vaginal delivery. The assumption is that uterine entry makes rupture more likely, but there’s not much evidence to support that idea, and it’s become clear in recent years that women who have a significant full-thickness insult to uterine integrity – a prior C-section – can usually deliver vaginally with no problem. In short, the uterus seems to have a remarkable ability to heal itself.

Even so, there are still ob.gyns. who pressure women into having premature babies if they’ve had a fibroid removed even without cavity entry. Barring additional indications, that doesn’t happen anymore at Northwestern University, said lead investigator Nathan King, MD, an ob.gyn. resident at the university.

The Northwestern team wanted to clear the fog. What they found adds to “literature that demonstrates the overall low risk of undergoing VTOL [vaginal trial of labor] after a prior myomectomy. We hope providers will feel more comfortable talking to their patients about delivery [options] and the success of VTOL after myomectomy,” Dr. King said at a meeting sponsored by AAGL.*

He and his team analyzed pregnancy outcomes in 112 women who had a live birth after non–cavity-entering myomectomies. Forty-nine women (44%) were allowed to undergo VTOL; 63 others had C-sections, most at term.

Thirty-two VTOL women (65%) had vaginal deliveries, a success rate similar to that of labor after C-section. There was just one uterine rupture in the VTOL group, for an incidence of 2%, which also was comparable to the rupture risk after a low-transverse C-section.

The rupture was discovered after spontaneous vaginal delivery, and an addressed by laparotomy. Both mother and infant were fine.

Adverse events were less likely in the VTOL group, regardless if they ultimately delivered vaginally or by C-section. The lower adverse event rate was driven by fewer postpartum hemorrhages (odds ratio, 0.441, 95% confidence interval, 0.2002-0.9722, P = .042).

There were no demographic difference between women who were allowed to undergo VTOL and those who were not. For most, it was their first delivery.

Women who had their uterine cavities entered during myomectomy weren’t allowed to undergo VTOL at Northwestern, and were not included in the analysis. Also, the study did not include women who became pregnant after myomectomy, but did not have a live delivery. The incidence of uterine rupture among them, if any, was not reported.

There was no external funding for the work, and Dr. King didn’t have any disclosures.

SOURCE: King N et al. 2018 AAGL Global Congress, Abstract 162.

*Correction, 12/11/2018: An earlier version of this story misstated the name of the meeting sponsor. It is AAGL.

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