Differences in optimality index between planned place of birth in a birth centre and alternative planned places of birth, a nationwide prospective cohort study in The Netherlands: results of the Dutch Birth Centre Study.

Objectives To compare the Optimality Index of planned birth in a birth centre with planned birth in a hospital and planned home birth for low-risk term pregnant women who start labour under the responsibility of a community midwife. Design Prospective cohort study. Setting Low-risk pregnant women under care of a community midwife and living in a region with one of the 21 participating Dutch birth centres or in a region with the possibility for midwife-led hospital birth. Home birth was commonly available in all regions included in the study. Participants 3455 low-risk term pregnant women (1686 nulliparous and 1769 multiparous) who gave birth between 1 July 2013 and 31 December 2013: 1668 planned birth centre births, 701 planned midwife-led hospital births and 1086 planned home births. Main outcome measurements The Optimality Index NL-2015, a tool to measure 'maximum outcome with minimal intervention', was assessed by planned place of birth being a birth centre, a hospital setting or at home. Also, a composite maternal and perinatal adverse outcome score was calculated for the different planned places of birth. Results There were no differences in Optimality Index NL-2015 for pregnant women who planned to give birth in a birth centre compared with women who planned to give birth in a hospital. Although effect sizes were small, women who planned to give birth at home had a higher Optimality Index NL-2015 than women who planned to give birth in a birth centre. The differences were larger for multiparous than for nulliparous women. Conclusion The Optimality Index NL-2015 for women with planned birth centre births was comparable with planned midwife-led hospital births. Women with planned home births had a higher Optimality Index NL-2015, that is, a higher sum score of evidence-based items with an optimal value than women with planned birth centre births.