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

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.