Objective: To assess incidence of uterine rupture in scarred and unscarred uteri and its maternal and fetal complications in a nationwide design.
Design: Population-based cohort study.
Setting: All 98 maternity units in The Netherlands.
Population: All women delivering in The Netherlands between August 2004 and August 2006 (n = 371,021).
Methods: Women with uterine rupture were prospectively collected using a web-based notification system. Data from all pregnant women in The Netherlands during the study period were obtained from Dutch population-based registers. Results were stratified by uterine scar.
Main outcome measures: Population-based incidences, severe maternal and neonatal morbidity and mortality, relative and absolute risk estimates.
Results: There were 210 cases of uterine rupture (5.9 per 10,000 pregnancies). Of these women, 183 (87.1%) had a uterine scar, incidences being 5.1 and 0.8 per 10,000 in women with and without uterine scar. No maternal deaths and 18 cases of perinatal death (8.7%) occurred. The overall absolute risk of uterine rupture was 1 in 1709. In univariate analysis, women with a prior caesarean, epidural anaesthesia, induction of labour (irrespective of agents used), pre- or post-term pregnancy, overweight, non-Western ethnic background and advanced age had an elevated risk of uterine rupture. The overall relative risk of induction of labour was 3.6 (95% confidence interval 2.7-4.8).
Conclusion: The population-based incidence of uterine rupture in The Netherlands is comparable with other Western countries. Although much attention is paid to scar rupture associated with uterotonic agents, 13% of ruptures occurred in unscarred uteri and 72% occurred during spontaneous labour.