Revisiting maternal age and child health: A nationwide birth cohort study in Taiwan.

Background: Delayed childbearing is a growing trend globally, with Taiwan experiencing one of the steepest increases in maternal age. Advanced maternal age affects offspring health, including birth outcomes and long-term morbidity. However, its impact in Taiwan remains underexplored. This study investigates these effects using a nationwide birth cohort.

Methods: This retrospective cohort study utilized data from Taiwan's National Health Insurance Research Database (NHIRD), covering infants born from January 1, 2004, to December 31, 2014. The cohort included 2,068,672 infants, categorized into six maternal age groups: <20, 20-24, 25-29, 30-34, 35-40, and ≥40 years. Principal outcomes were stillbirth, mortality, preterm birth, congenital anomalies, neurodevelopmental outcomes, and atopic diseases. Multivariate logistic regression models adjusted for covariates to assess associations between maternal age and health outcomes.

Results: Among the 2,068,672 infants, stillbirth and mortality rates were highest in infants born to mothers <20 years, decreased with increasing maternal age, then rose again for mothers ≥30 years, showing a reverse J-shaped pattern. Similar trends were noted for preterm birth, congenital anomalies, and neurodevelopmental outcomes. Atopic diseases followed a nonlinear trend, peaking at maternal age 25-34 years.

Conclusion: Maternal age significantly impacts child health, with risks associated with both younger and older maternal ages. These findings are crucial for regions experiencing delayed childbearing. Further research is needed to explore underlying mechanisms and establish causality.