Background: There has been an increase in early-term planned births (prelabour caesarean or labour induction at 37–38 weeks gestation).
Aim: To determine factors associated with early-term planned birth and to assess to what extent these factors explain the increase in these births in New South Wales.
Methods: A population-based linked data cohort study of all liveborn singleton births between 33 and 40 weeks gestation in New South Wales between 2005 and 2015. The outcome was early-term planned birth. Multilevel multivariable models were used to examine the association between year of birth and early-term planned birth (compared with full term births), adjusting for year, maternal and hospital characteristics.
Results: There were 932,882 singleton births in NSW between 33 and 40 weeks gestation. The proportion of early term planned births increased over the study period by 39%, from 12 to 17%. The characteristics that explained the most variation in early-term planned births were previous caesarean, pregnancy hypertension, gestational diabetes, maternal age and the type of hospital (public vs. private). Among women who had a previous caesarean, were ≥30 years old, had gestational diabetes or gave birth in a private hospital, there was an increase in the proportion of births that were early-term planned (p<0.001 for all).
Conclusion: Maternal and hospital characteristics explained a small proportion of the increase in early planned births, with the most influential characteristics being previous caesarean birth, pregnancy hypertension, gestational diabetes, maternal age, and the type of hospital (public vs. private).