Stern JE, et al. - This retrospective cohort study determined the impact of medical and obstetrical factors on the odds of cesarean delivery, comparing assisted reproductive technology (ART)–treated women and women with subfertility not treated with ART vs fertile women. Compared with fertile women, ART and unassisted infertility were correlated with greater odds of cesarean. Researchers reported that obstetrical risks and underlying medical had strong confounding impacts strongly attenuating the odds for cesarean delivery. It was noted that age and previous uterine surgery were the strongest confounders of odds of cesarean delivery.

Methods

• Researchers used data regarding singleton deliveries to primiparous women from the Massachusetts vital and hospital records linked to the Society for Assisted Reproductive Technology Clinic Outcome Reporting System data (2004-2010).
• Main outcome measure was mode of delivery.

Results

• The study results showed that the 173,130 deliveries included 5,768 ART-treated, 2,657 subfertile (1,627 non-ART medically assisted reproduction [MAR] and 1,030 unassisted infertile), and 164,705 fertile pregnancies and 117,743 vaginal and 55,387 cesarean deliveries.
• It was observed that ART-treated women were older, more often white and non-Hispanic, and with more private insurance, previous uterine surgery, gestational diabetes, pregnancy hypertension, bleeding, and placental complications than fertile women.
• They found that rates of cesarean delivery were 45.7%, 43.3%, and 31.1% for ART-treated, subfertile, and fertile women and 41.7% and 45.9% for MAR and unassisted infertile deliveries.
• It was noted that underlying medical factors, previous uterine surgery, and placental and delivery complications, adjusted odds ratios (ORs) compared with fertile women were 1.27 for ART-treated and 1.15 for subfertile women, with greater odds among unassisted infertile (OR 1.26) but not MAR (OR 1.09) women, when adjusted for demographics.
• Age and previous uterine surgery were the strongest confounders of odds of cesarean delivery.