Model of Care and Chance of Spontaneous Vaginal Birth: A Prospective, Multicenter Matched-Pair Analysis From North Rhine-Westphalia

Background: Compared to standard obstetric care, advantages of midwife-led models of care have been reported; these include a higher vaginal birth rate and less interventions. In Germany, 98.4% of women are giving birth in consultant-led obstetric units. We compared the outcome of birth planned in alongside midwifery units (AMU) in North Rhine-Westphalia (NRW) with a matched group of low-risk women who gave birth in standard obstetric care during the same period of time. Methods: A prospective, controlled, multicenter study was conducted. Six of the seven AMUs in NRW participated. Healthy women with a singleton term cephalic pregnancy booking for birth in AMU were eligible. For each woman in the study group a control was chosen who would have been eligible for birth in AMU but was booking for standard obstetric care at the same hospital at the same time; additionally, matching for parity was performed. Mode of birth was chosen as primary outcome parameter. Secondary endpoints included a composite outcome of abnormal third stage and / or postpartum hemorrhage; higher-order obstetric lacerations; and for the neonate, a composite outcome (5-minute Apgar <7 and / or umbilical cord arterial pH < 7.10 and / or transfer to specialist neonatal care). Statistical analysis was by intention to treat. A non-inferiority analysis was performed for the primary and all secondary endpoints. Results: 589 case-control pairs were recruited, corresponding to 13.6% of those assumed to be eligible; 198 cases were excluded. Final analysis was performed with 391 case-control pairs. Nulliparous women constituted 56.0% of cases. For the primary endpoint vaginal birth superiority was established for the study group (5.66, 90%-CI 1.26-10.04). Superiority was also confirmed for higher-order obstetric lacerations (2.33, 90%-CI 0.04-4.81). For the composite newborn outcome non-inferiority was established (1.28, 90%-CI 1.33-3.93). Non-inferiority was not present for the composite maternal outcome (-1.56, 90%-CI -5.86-2.75). The epidural anesthesia rate was lower (22.9% vs. 41.1%), and the length of hospital stay was shorter in the study group (p<0.001 for both).Transfer to standard obstetric care occurred in 51.2% of cases, with a strong association between parity and transfer (p<0.001). Request for regional anesthesia was the most common cause for transfer (47.1%). Conclusion: Our comparison between care in AMU and standard obstetric care with respect to mode of birth and other outcomes confirmed the superiority of this model of care for low-risk women. Admission and transfer criteria were in place in all participating centers and strictly adhered to.