Is the obstetric outcome of in vitro fertilized singleton gestations different from natural ones? A controlled study.

OBJECTIVE: To determine whether singleton IVF pregnancies carry adverse maternal or fetal outcome when compared with naturally conceived gestations.
DESIGN: An analysis of the obstetric outcome of singleton IVF pregnancies in comparison with matched, naturally conceived singleton controls.
SETTING: In vitro fertilization unit and obstetric service at a tertiary medical center. PATIENT(S): Two hundred sixty consecutive singleton IVF pregnancies and 260 naturally conceived singleton controls matched 1:1 for maternal age, parity, ethnic origin, and location and date of delivery. INTERVENTION(S): In vitro fertilization-ET. MAIN OUTCOME MEASURE(S): The rate of antenatal obstetric complications, nonvertex presentation, cesarean section, preterm labor, low birth weight, small and very small for gestational age, neonatal intensive care unit admissions, and perinatal mortality. RESULT(S): The rates of most antenatal complications were similar in both groups. Urinary tract infection was the only complication diagnosed significantly more frequently after IVF (7.3% versus 1.2%); however, the rates of severe urinary tract infection necessitating hospitalization were similar. The incidence of nonvertex presentation was also similar. The cesarean section rate was significantly higher among IVF patients (41.9% versus 15.5%). The rates of preterm labor, low birth weight, small and very small for gestational age, neonatal intensive care unit admissions, and perinatal mortality were comparable. CONCLUSION(S): When controlling for maternal age, parity, ethnic origin, and location and date of delivery, singleton IVF pregnancies do not carry an increased risk for prematurity, low birth weight, or maternal or fetal complications. Still, these pregnancies are associated with a high rate of cesarean sections.