Planned place of birth in New Zealand: does it affect mode of birth and intervention rates among low-risk women?

Background: Midwives providing care as lead maternity caregivers in New Zealand provide continuity of care to women who may give birth in a variety of settings, including home, primary units, and secondary and tertiary level hospitals. The purpose of this study was to compare mode of birth and intrapartum intervention rates for low-risk women planning to give birth in these settings under the care of midwives.

Methods: Data for a cohort of low-risk women giving birth in 2006 and 2007 were extracted from the Midwifery Maternity Provider Organisation database. Mode of birth, intrapartum interventions, and neonatal outcomes were compared with results adjusted for age, parity, ethnicity, and smoking.

Results: Women planning to give birth in secondary and tertiary hospitals had a higher risk of cesarean section, assisted modes of birth, and intrapartum interventions than similar women planning to give birth at home and in primary units. The risk of emergency cesarean section for women planning to give birth in a tertiary unit was 4.62 (95% CI: 3.66-5.84) times that of a woman planning to give birth in a primary unit. Newborns of women planning to give birth in secondary and tertiary hospitals also had a higher risk of admission to a neonatal intensive care unit (RR: 1.40, 95% CI: 1.05-1.87; RR: 1.78, 95% CI: 1.31-2.42) than women planning to give birth in a primary unit.

Conclusions: Planned place of birth has a significant influence on mode of birth and rates of intrapartum intervention in childbirth.