Maternal age and emergency operative deliveries at term: a population-based registry study among low-risk primiparous women

ObjectiveTo study the association between maternal age and emergency operative delivery. The roles of in-labour indications, and birthweight4000g, gestational age42weeks, induction of labour, and epidural use, according to maternal age were explored. DesignPopulation-based study. SettingMedical Birth Registry of Norway and Statistics Norway. PopulationWe studied 169583 low-risk primiparous mothers with singleton, cephalic labours, at 37weeks of gestation, from 1999 to 2009. MethodsThe associations between maternal age and mode of delivery were analysed using multinomial regression analyses, adjusting for sociodemographic factors. Main outcome measuresEmergency caesarean section and operative vaginal delivery. ResultsOf women aged 40years, 22% had emergency caesarean sections and 24% had operative vaginal deliveries, giving adjusted relative risk ratios (RRRs) of 6.60 (95% confidence interval, 95%CI 5.53-7.87) and 3.30 (95%CI 2.79-3.90), respectively, when compared with women aged 20-24years. Adjustments for sociodemographic factors only slightly changed the estimates. Dystocia was the main indication, followed by fetal distress. All of the listed factors increased the level of emergency operative deliveries, mainly because of an increase in dystocia. The increase in risk for emergency caesarean section by all factors, and for operative vaginal deliveries by epidural, were greater in older than in younger women, but were significant for epidural only. ConclusionsWe found a close association between maternal age andemergency operative delivery in low-risk primiparas. Contributory factors increased the risk for both emergency operative delivery and epidural more in older than in younger women.