The effects of maternal age and parity on maternal and neonatal outcome

Delayed childbearing is increasingly common; hence, concerns emerge regarding potential for additional risks of delivery at advanced maternal age (AMA; ≥35 years). In this study, we sought to assess impact of AMA and parity on maternal and perinatal outcomes.

In this retrospective single-center study (July 2005 to October 2011), we compared spontaneously-conceived singleton births of AMA mothers with spontaneously-conceived singletons of mothers aged 24-27 years. Maternal outcomes: incidence of diabetes, hypertension, and emergency cesarean sections (ECS). Neonatal outcomes: prematurity, birth weight, incidence of small or large for gestational age infants (SGA/LGA, respectively), low birth weight (LBW), and 5'-Apgar scores. Sub-groupings of maternal age were 35-38, 39-42, or 43-47 years; prematurity as <34 or <37 weeks; AMA parity as primiparous, 2-5 births, 6-9 births, or ≥10 births. Binary logistic regression was used for multivariate analyses.

Of 24,579 eligible women, 11,243 were AMA (14.0% total singleton births) and 13,336 were aged 24-27 years (16.7% total singleton births) at delivery. There were no maternal or perinatal deaths. Incidence of maternal hypertension and diabetes was significantly greater in AMA, especially oldest AMA. AMA including primiparous had significantly more ECS than younger including primiparous controls, respectively, and were more likely to deliver LGA neonates. Primiparous AMA women did not have increased incidence of LGA babies but significantly increased incidence of SGA infants.

AMA, especially primiparous, has more adverse maternal and neonatal outcomes than younger women; however, these did not include mortality. Consistent antenatal care may explain this.