Perinatal outcomes of women undergoing cesarean delivery after prior myomectomy

Background: The American College of Obstetricians and Gynecologists recommends that women who have had a prior myomectomy that entered the endometrial cavity undergo cesarean delivery in order to avoid the possible complication of uterine rupture. Women with prior myomectomies may also have intraabdominal adhesions, complicating future surgery and if myomas remain after myomectomy, they may have more bleeding complications during their subsequent pregnancies.Objectives: The purpose of this study was to evaluate maternal and neonatal outcomes after prior myomectomy in women undergoing planned cesarean delivery.Study design: We conducted a retrospective cohort study using the Maternal Fetal Medicine Units Cesarean Registry database comparing women undergoing a cesarean delivery with a history of prior myomectomy to women undergoing a cesarean delivery without a history of a prior myomectomy. Inclusion criteria were singleton gestations at term undergoing planned cesarean delivery. Exclusion criteria were stillbirth, cesarean delivery indication for nonreassuring fetal heart rate, macrosomia, abruption, previa or women undergoing planned trial of labor after cesarean. Primary outcome was incidence of blood transfusion. Maternal and neonatal outcomes were compared secondarily. Logistic regression was used to adjust for confounders.Results: The entire study population included 73,257 deliveries; 34,002 women met inclusion criteria, of which 367 had a prior myomectomy and 33,635 were controls. The demographics, which varied by maternal age, race and number of prior cesareans were adjusted for when calculating maternal outcomes. The rate of intraoperative transfusion in the prior myomectomy group was 1.4% (5/367) compared to 0.4% (131/33,635) in the control group (aOR 2.8; 95% CI 1.15-6.79). The prior myomectomy group had a higher incidence of postpartum transfusion rate (2.5%, 9/367) compared to the control group (1.2%, 416/33,635) (aOR 2.03; 1.06-3.92), uterotonic usage (5.4%, 20/367) compared to the control group (3.5%, 1165/33,635; aOR 1.57; 95% CI 1.01-2.45), bowel injury (0.5%, 2/367) compared to the control group (0.0%, 14/33,635; aOR 8.13; 95% CI 2.05-32.28) and cesarean hysterectomy (1.4%, 5/367) compared to the control group (77/33,635; aOR 3.43; 95% CI 1.32-8.91). Neonatal outcomes were not different between groups.Conclusion: Prior myomectomy in women with term, singleton gestations undergoing planned cesarean delivery was associated with an 180% increased risk of intraoperative transfusion compared to the control group. We also found that women in the myomectomy group are 57% more likely to use uterotonics, 713% more likely to experience a bowel injury, 243% more likely to undergo a cesarean hysterectomy, and 227% more likely to need a classical uterine incision during delivery. Neonatal morbidity was not statistically different between the groups.