606 Association between in vitro fertilization and cesarean delivery among laboring nulliparous women

Abstract

Exposure to in vitro fertilization (IVF) has been associated with an increased risk for cesarean delivery (CD). The aim of this study was to determine whether term nulliparous patients who conceived by IVF and labored are more likely to experience CD compared with patients who conceived without IVF (spontaneously, by induction of ovulation, or artificial insemination). Secondary analysis of a multicenter randomized trial in which low-risk nulliparous patients were assigned to induction of labor at 39 weeks or expectant management, at 41 hospitals across the US. Patients with antepartum stillbirth, major congenital malformations, and those who underwent elective, or pre-labor CD were excluded. The primary outcome for this analysis was CD. Univariate followed by multivariable analyses were conducted adjusting for advanced maternal age, obesity, private insurance, and treatment group. Mediation analysis was implemented considering type of labor, chorioamnionitis, hypertensive disorder of pregnancy, and dilation (≥ 5 cm and complete). P value of <0.05 was considered statistically significant. Of the 6,024 patients included in the analysis, 102 (1.7%) had IVF and these were more likely to be older, of White race, privately insured, married or living with a partner, and have had a prior pregnancy loss (all p< 0.01, Table 1). There were no significant differences in obstetrical characteristics (e.g. gestational age at delivery, type of labor, ripening agents or oxytocin use, or labor progress) or intrapartum morbidities (preeclampsia, abruption, or chorioamnionitis) between the two groups (Table 2). However, patients who conceived by IVF had higher odds of CD (30.4% vs. 19.5%, aOR 1.69, 95% CI 1.07-2.67, p=0.04) after adjusting for covariates. The mediating variables considered were not statistically significant with IVF, although the data are sparse. IVF was found to be associated with an increased odds of CD in laboring nulliparous women. These results may be of use for patient counseling before infertility treatment and at delivery time.View Large Image Figure ViewerDownload Hi-res image Download (PPT)