Discussion
Principal findings
The incidence of adverse perinatal outcomes was low in all
settings. There was no difference overall between birth settings
in the incidence of the primary outcome (composite of perinatal
mortality and intrapartum related neonatal morbidities), but
there was a significant excess of the primary outcome in births
planned at home compared with those planned in obstetric units
in the restricted group of women without complicating
conditions at the start of care in labour. In the subgroup analysis
stratified by parity, there was an increased incidence of the
primary outcome for nulliparous women in the planned home
birth group (weighted incidence 9.3 per 1000 births, 95%
confidence interval 6.5 to 13.1) compared with the obstetric
unit group (weighted incidence 5.3, 3.9 to 7.3). The sensitivity
analysis restricted to units or trusts with a high response rate
suggested some uncertainty around the risk of the primary
outcome for planned births in freestanding midwifery units for
nulliparous women, but this may have been a chance finding.
For multiparous women, there were no significant differences
in the primary outcome between birth settings.
Women with planned births at home or in freestanding or
alongside midwifery units were significantly less likely than
those with planned births in obstetric units to have an
instrumental or operative delivery or to receive medical
interventions such as augmentation, epidural or spinal analgesia,
general anaesthesia, or episiotomy and significantly more likely
to have a “normal birth.”