Maternal age 30-34 years and adverse perinatal outcomes: a systematic review and meta-analysis.

Background: Globally, births to women in their early thirties have become more prevalent. The current study aimed to examine the association of maternal age (30-34 years) with adverse perinatal outcomes, especially congenital birth defects and stillbirth. Methods: A literature search was conducted using PubMed, Web of Science, and Google Scholar for relevant studies published between July 1989 and August 2025. The primary outcomes were congenital birth defects (i.e., composite of Down syndrome and structural birth defects) and stillbirth. The secondary outcomes were preterm birth, low birthweight (LBW), neonatal mortality, small-for-gestational age (SGA), and intrauterine growth restriction (IUGR). Adverse perinatal outcomes were examined in women aged 30-34 compared with younger cohorts aged 18-29 years. The quality of the included studies and potential publication bias were evaluated. For the meta-analysis, forest plots were created for each outcome, and heterogeneity was assessed using the I Results: Sixty studies were included in this meta-analysis. Maternal age (30-34 years) was associated with a significantly higher risk of overall congenital birth defects (OR, 1.10; 95% CI, 1.03, 1.17; Conclusion: Maternal age 30-34 years was associated with a significantly higher risk of congenital birth defects, especially Down syndrome, but was not associated with other adverse perinatal outcomes, when compared to the 18-29 age group. Systematic review registration: https://www.crd.york.ac.uk/prospero/, identifier CRD420251105683.