The relationship between midwife-led group-based versus conventional antenatal care and mode of birth: a matched cohort study

Background: Midwife facilitated, group models of antenatal care have emerged as an alternative to conventional care both within Australia and internationally. Group antenatal care can be offered in a number of different ways, however usually constitutes a series of sessions co-ordinated by a midwife combining physical assessment, antenatal education and peer support in a group setting. Midwife-led group antenatal care is viewed positively by expectant mothers, with no associated adverse outcomes identified in the published literature for women or their babies when compared with conventional care. Evidence of an improvement in outcomes is limited. The aim of this study was to compare mode of birth (any vaginal birth with caesarean birth) between pregnant women accessing midwife-led group antenatal care and conventional individual antenatal care, in Queensland, Australia. Methods: This was a retrospective matched cohort study, set within a collaborative antenatal clinic between the local university and regional public health service in Queensland, Australia. Midwife-led group antenatal care (n = 110) participants were compared with controls enrolled in conventional antenatal care (n = 330). Groups were matched by parity, maternal age and gestation to form comparable groups, selecting a homogeneous sample with respect to confounding variables likely to affect outcomes. Results: There was no evidence that group care resulted in a greater number of caesarean births. The largest increase in the odds of caesarean birth was associated with a previous caesarean birth (p < 0.001), no previous birth (compared with previous vaginal birth) (p < 0.003), and conventional antenatal care (p < 0.073). The secondary outcomes (breastfeeding and infant birth weight) which were examined between the matched cohorts were comparable between groups. Conclusions: There is no evidence arising from this study that there was a significant difference in mode of birth (caesarean or vaginal) between group and conventional care. Group care was associated with a lower risk of caesarean birth after controlling for previous births, with the highest chance for a vaginal birth being a woman who has had a previous vaginal birth and was in group care. Conversely, the highest risk of caesarean birth was for women who have had a previous caesarean birth and conventional care.