219: Trial of labor versus primary cesarean delivery in women with extreme obesity


      It is unclear whether a trial of labor (TOL) is safe for women with extreme obesity intending vaginal delivery. The objective of this study is to assess maternal and neonatal outcomes among women with extreme obesity who undergo a primary CD versus a TOL.

      Study Design

      This is a retrospective cohort study of all deliveries ≥36 weeks’ gestation in the State of California between 2007-2011. Data were extracted from maternal discharge data linked to infant birth certificate records. Included were all women with a body mass index (BMI) ≥50. Excluded were multiple gestations and women undergoing a trial of labor (TOL) after CD or a repeat CD. The primary outcome was severe maternal mortality or death (SMMD). Our secondary outcome was a composite of neonatal morbidity or death.


      Of the 1,115,876 women who underwent either a TOL or a primary CD, our cohort comprised 2,693 women (0.24%) with a BMI ≥ 50. In our cohort, 71% (1918) underwent a TOL and 29% (775) a primary CD. The overall CD rate was 39%, of which 15% underwent a TOL. Rates of maternal and neonatal morbidities are presented in Table. Compared to primary CD, women undergoing TOL had a reduced risk of SMMD (0.6% vs 1.4%, RR 0.40, 95% CI 0.28-0.81). Women undergoing CD after a TOL were at increased risk of SMMD compared to women undergoing vaginal delivery (1.7% vs 0.4%, RR 4.7, 95% CI 1.5-15.4), whereas the risks of SMMD were not significantly different between women undergoing CD after TOL vs. primary CD (1.7% vs 1.4%, RR 1.22, 95% CI 0.43-3.50). NICU admission was significantly reduced among women with a TOL but there were no differences in the overall rate of neonatal morbidity compared to women with a primary CD. A successful TOL was associated positively with parity and negatively with maternal age and hypertensive disorders.


      Among women with extreme obesity, a TOL and primary CD have similar associated morbidities Primary CD does not appear to reduce these morbidities.
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