Inter-pregnancy interval after caesarean section and subsequent pregnancy outcomes in New South Wales. A data linkage cohort protocol.

Caesarean section (CS) rates are increasing worldwide. CS and repeat caesarean alter the risk profile for next pregnancy. Interpregnancy interval (IPI) has been shown to modify maternal and neonatal risk in subsequent pregnancies. There is limited research in the Australian context addressing outcomes relative to interpregnancy interval. The lack of pregnancy spacing information adds to confusion and conflicting recommendations for maternity care providers and women. We developed a protocol using data linkage of routinely collected hospital data from 1994 to 2023 in New South Wales, Australia to investigate both maternal and neonatal outcomes relative to interpregnancy intervals.•Large scale study of interpregnancy interval after CS in an Australian multiethnic cohort not previously explored•Quantify the risks associated with differing interpregnancy intervals compared to contemporaneous controls in this cohort•Results presented as absolute risk facilitating access to evidence-based information.