Advanced maternal age increases the risk of adverse neonatal outcomes: a comparative study in Ethiopia

Adverse neonatal outcomes (ANOs), including preterm birth, low birth weight, low Apgar scores, congenital malformations, and early neonatal death, remain a leading cause of neonatal and infant mortality worldwide. Pregnancy at advanced maternal age (> 35 years) increases the risk of ANOs, even in the absence of other socio-economic or medical risk factors. In developing countries such as Ethiopia, where neonatal mortality is high, evidence on the impact of advanced maternal age on neonatal outcomes is limited. This highlights the need for context-specific research to inform maternal and neonatal health interventions.

This study aimed to compare adverse neonatal outcomes and associated factors among adult and advanced-aged pregnant mothers at the public hospitals of Addis Ababa City.

A hospital-based comparative cross-sectional study was conducted at public hospitals in Addis Ababa from April 29 to June 30, 2024, among 707 mothers (471 adults and 236 advanced-age). Data were collected using a systematic random sampling technique and the Open Data Kit (ODK) Collect Android application. Analyses were performed with SPSS version 26.0. Independent t-tests were used to compare continuous outcome variables between groups and estimate mean differences, while binary logistic regression analyses were employed to estimate COR and AOR with a CI of 95%. A p-value < 0.05 was considered statistically significant.

The overall response rate was 98.6%. Nearly half of advanced-aged mothers (51.5%; 95% CI: 44.7-57.9) experienced at least one ANO, compared to 40.2% (95% CI: 35.7-44.6) among adult-aged mothers, yielding a proportion difference of 11.3% (95% CI: 3.5-19.1). Overall, 44.0% (95% CI: 40.2-47.6) of neonates experienced at least one ANO. Advanced maternal age was significantly associated with unfavorable neonatal outcomes [AOR = 1.51; 95% CI: 1.02-2.25]. Specifically, advanced age was linked to increased risks of preterm birth [AOR = 1.84; 95% CI: 1.18-2.85] and large for gestational age [AOR = 2.68; 95% CI: 1.31-5.49], while it was inversely associated with post-term birth [AOR = 0.25; 95% CI: 0.08-0.83].

Advanced maternal age was significantly associated with increased ANOs, particularly preterm birth, and large for gestational age. To mitigate these risks, there is a need for strategy development that creates awareness on the advantages of achieving the desired number of children during early adulthood, alongside strengthening risk-based antenatal care in Ethiopia.