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

Objective To study the association between maternal age and emergency operative delivery. The roles of in‐labour indications, and birthweight ≥ 4000 g, gestational age ≥ 42 weeks, induction of labour, and epidural use, according to maternal age were explored. Design Population‐based study. Setting Medical Birth Registry of Norway and Statistics Norway. Population We studied 169 583 low‐risk primiparous mothers with singleton, cephalic labours, at ≥37 weeks of gestation, from 1999 to 2009. Methods The associations between maternal age and mode of delivery were analysed using multinomial regression analyses, adjusting for sociodemographic factors. Main outcome measures Emergency caesarean section and operative vaginal delivery. Results Of women aged ≥40 years, 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 20–24 years. 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. Conclusions We found a close association between maternal age and emergency 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.