Objective: Our objective was to test the hypothesis that pregnancies beyond 20 weeks in women aged 35 or older are high-risk pregnancies.
Study design: Pregnancies of 857 women aged 35 and older were compared with pregnancies of 1597 women aged 20 to 29 with respect to pregnancy complications and outcome. All women received prenatal care and were delivered at our institution. Data were collected prospectively and stored in a data base. The chi 2 test was used to identify trends in individual variables and outcomes. Logistic regression analysis was used to examine the relationship between maternal age and delivery by cesarean section.
Results: Women aged 35 or older had cesarean deliveries twice as often as women 20 to 29 years old. This statistically significant difference was not accounted for by the modestly higher rates of fetal distress, placenta previa, multiple gestation, abnormal labor, or malpresentation found in the older group. Cord blood gas values and 5-minute Apgar scores did not differ between the two groups. There was no difference in neonatal morbidity or mortality.
Conclusions: Women of 35 or older are more likely than those in their 20s to have cesarean deliveries. The excess rate of cesarean section is only partially accounted for by gestational complications.