Which Adverse Pregnancy Outcomes Increase with Maternal Age?

Excess risk for fetal chromosomal abnormalities is well established in older mothers, but risks for other adverse pregnancy outcomes are less clearly defined. To determine risk estimates for such outcomes, investigators examined prospectively collected data on >350,000 pregnant women in Denmark from 2008 through 2014.

Overall risk for adverse outcomes (collectively defined as chromosomal abnormalities, congenital malformations, miscarriage, stillbirth, or preterm birth) was 5% (maternal age range, 20–34), 7% (age range, 35–39), and 11% (aged ≥40). The excess risk among women aged ≥40 was driven predominantly by increased probability of chromosomal abnormalities (odds ratio, 7), miscarriage (OR, 4), and preterm birth (OR, 2) compared with tho…