Risk factors for cesarean section of primiparous women aged over 35 years

Background. To determine the perinatal outcome of pregnancy in primiparous women over 35 years of age and to evaluate determinants predicting cesarean delivery in these women. Methods. Two hundred and seven mothers aged at least 35 years (1.8% of the total deliveries) delivered in the Department of Obstetrics and Gynecology between 1995 and 2000. These women were matched with women aged 20-29 years according to gravidity. Multiple logistic regression analysis was used to evaluate the risk of cesarean delivery, with controls for possible confounding factors. Results. Cesarean section was 2.09-fold more prevalent among the older than among the younger women; the difference being significant (odds ratio, OR=3.36, 95%CI 2.22-5.09; p<0.001). The advanced maternal age was associated with a significantly higher rate of assisted reproductive techniques involvement (OR 6.54; 95%CI 3.54-12.38; p<0.001). The difference between the rates of preeclampsia in the two groups did not reach the level of significance (OR 1.85; 95%CI 1.02-3.34; p=0.056). There were no significant differences in perinatal outcome between the two groups. The logistic regression model demonstrated an increased risk of cesarean section among the primiparous women aged over 35 years. Conclusions. The risk of cesarean section at this advanced age is 6.54-fold. The determinants are included in the pregnancy, delivery and neonatal outcome.