Is advanced maternal age an independent risk factor for uteroplacental insufficiency?

Objective: To determine whether maternal age 35 years or older is an independent risk factor for uteroplacental insufficiency and thus an independent indication for antepartum testing. Study design: A retrospective cohort analysis was performed of all deliveries at Los Angeles County-University of Southern California Women's and Children's Hospital between August 1, 1995, and September 1, 2003. Women with documented indications for antepartum testing, fetal anomalies, or delivery prior to 34 weeks were excluded from analysis. Markers of uteroplacental insufficiency included stillbirth, birth weight less than the 10th percentile, fetal distress, cesarean section for fetal distress, oligohydramnios, meconium passage, and 5-minute Apgar score less than 7. Results: Indications for antepartum testing were significantly more common in women 35 years or older (33.2% versus 27.0%). After excluding women with indications for antepartum testing, anomalous fetuses, and women delivering prior to 34 weeks, stillbirth was twice as common in women 35 years and older. However, among stillbirths, growth restriction occurred with similar frequency in the older (28.6%) and younger (25.0%) cohorts. Among live births, 2 markers of uteroplacental insufficiency, intrapartum fetal distress (5.7% versus 4.1%) and cesarean delivery for fetal distress (4.0% versus 2.4%) were significantly more common in the older cohort. All other markers of uteroplacental insufficiency were observed with similar frequency in the 2 groups. Conclusions: After excluding women with other indications for antepartum testing, fetal anomalies, and delivery prior to 34 weeks, stillbirth was twice as common in women 35 years of age or older as in those younger than 35 years. The increased rate of stillbirth does not appear to be explained by a higher rate of uteroplacental insufficiency.