Neonatal Outcomes Among Infants of Mothers With Advanced Maternal Age: A National Cohort Study.

Abstract

Aim: Maternal age has increased steadily worldwide over the last few decades. This study aimed to investigate how different degrees of advanced maternal were associated with adverse neonatal outcomes.

Methods: A nationwide register-based study was conducted using the Swedish Medical Birth Register. This comprised all singleton births to women aged 35 years plus from 2010 to 2022. The women were divided into three groups based on maternal age: 35-39 was the reference group, and 40-44 and 45 years plus were the advanced and very advanced maternal age groups, respectively.

Results: We studied 312 221 singleton pregnancies. There were increased odds risks (95% confidence intervals) for infants born to women aged 40-44 (17.8%) and 45 years plus (1.1%), compared to those aged 35-39. These included stillbirths at 1.27 (1.12-1.45) and 1.80 (1.24-2.61) and infants being small for gestational age at 1.26 (1.19-1.33) and 1.46 (1.22-1.75). Risks for preterm birth, Apgar scores below seven at 5 min, and hypoglycaemia also increased.

Conclusion: Severe adverse neonatal outcomes were uncommon in Sweden but were higher in the advanced and very advanced maternal age groups than the younger reference group. Healthcare providers make women more aware of the risks of postponed childbearing.