Gestational age-specific risk of stillbirth during term pregnancy according to maternal age.

Abstract

To investigate the gestational age-specific risk of stillbirth according to the maternal age group particularly regarding stillbirth risk at the end of pregnancy. This study was a retrospective national cohort study of all singleton term pregnancy using the Korean Vital Statistics database (n = 2,798,542). We evaluated the risk of stillbirth by gestational week in mothers aged 20-49years according to maternal age group and neonatal birth weight. The risk of stillbirth in women aged 41years and older was significantly higher than in women aged 20-29years between 37 and 40weeks' gestation. The stillbirth rate per 10,000 ongoing pregnancy in women aged 37-38years at 39weeks' gestation (4.22, 95% confidence intervals [CI] 3.01-5.90) and that in women aged 39-40years at 40weeks' gestation (8.15, 95% CI 4.83-13.77) were significantly higher in comparison with in those aged 20-29years at 39weeks' gestation (1.95, 95% CI 1.64-2.33) and at 40weeks' gestation (2.59, 95% CI 2.1-3,18). The risk of stillbirth showed an increasing pattern at 40 gestational weeks, in women aged 39years and older. Delivery plan need to be set up and supported to decrease rates of stillbirth at term in women aged 35years and older with other risk factors and in women aged 37years and older regardless of risk factors, and especially in women older than 40years of age.