Pregnancy outcome at greater than or equal to 20 weeks' gestation in women in their 40s. A case-control study.

The obstetric performance of 166 women in their 40s who delivered during a one-year period at greater than or equal to 20 weeks' gestation was compared to that of a cohort of controls younger than 40. Medical complications--diabetes, chronic hypertension and antepartum bleeding--occurred more frequently in the older patients. They had a threefold increase in antepartum hospital admissions over the controls (23.5% vs. 7.8%). Both groups had the same perinatal mortality rate, 18/1,000, and their newborns had similar incidences of neonatal complications except for a higher frequency of major and minor congenital anomalies in the study group (16% vs. 8.4%). The older patients had a longer second stage of labor. Older nulliparas had a higher incidence of premature deliveries and cesarean sections than did their controls. The outcome of pregnancy in this age group is affected by multiple confounding variables; medical complications, parity and age play major roles.