- Objective: To compare the obstetric characteristics of singleton pregnancies conceived by IVF and ovulation induction with those conceived spontaneously. Design: Case-control study. Setting: Tertiary care medical center. Patient(s): All singleton pregnancies that were achieved by IVF (n = 169) and ovulation induction (n = 646) and were delivered from January 1989 through December 1994 were evaluated. Each group was compared with a separate control group that conceived spontaneously (n = 469 and n = 1,902 for the IVF and ovulation induction groups, respectively) and delivered during the same period and was matched in terms of maternal age, gestational age, and parity. Intervention(s): Ovulation induction, IVF-ET. Main Outcome Measure(s): Obstetric complications. Result(s): Multivariate analysis showed that patients who conceived by IVF and ovulation induction had a significantly higher risk for gestational diabetes mellitus (odds ratio [OR] = 2.0; 95% confidence interval [CI] = 1.23–3.30 and OR = 1.9, 95% CI = 1.09–1.79, respectively), pregnancy-induced hypertension (OR = 2.1, 95% CI = 1.04–4.10 and OR = 1.5, 95% CI = 1.04–2.02, respectively), and cesarean section (OR = 3.6, 95% CI = 2.44–5.29 and OR = 1.4, 95% CI = 1.09–1.79, respectively) compared with their matched controls. Conclusion(s): After controlling for maternal age, gestational age, and parity, we demonstrated that singleton pregnancies conceived by IVF and ovulation induction are at increased risk for maternal gestational diabetes mellitus and pregnancy-induced hypertension, and at greater risk for delivery by cesarean section.