Elevated risks of pregnancy complications and adverse outcomes with increasing maternal age

Abstract

Background: In the USA, between 1980 and 2004, the proportion of all births increased 2-fold in women aged ≥30, 3-fold in women aged ≥35 and nearly 4-fold in women aged ≥40. The objective of this study was to evaluate the risks of pregnancy complications and adverse outcomes with increasing maternal age using national vital statistics data. Methods: The study population included 8 079 996 live births of singletons of ≥20 weeks among women aged 30-54 from the 1995-2000 US Birth Cohort Linked Birth/Infant Death Data Set. Outcomes were modelled by maternal age and parity using multinomial logistic regression to calculate adjusted odds ratios (AORs) and 95% confidence intervals. Results: The risks for most outcomes paralleled increasing maternal age including prolonged and dysfunctional labour, excessive labour bleeding, breech and malpresentation and primary Caesarean delivery. The highest AORs among women aged ≥45 versus 30-34 by parity (primiparas and multiparas, respectively) were for chronic hypertension (3.70, 4.89), diabetes (2.19, 2.58), primary Caesarean (3.14, 2.85), excessive labour bleeding (1.54, 1.49), pregnancy hypertension (1.55, 2.13) and birth <32 weeks (2.11, 1.77). Conclusions: Increasing maternal age is associated with significantly elevated risks for pregnancy complications and adverse outcomes, which vary by parity. © 2007 Oxford University Press.