Office of Epidemiology and Research, Division of Research

Advancing Applied MCH Research

(SDAS) Improving Maternal And Child Health: Refining Understanding Of US Midwifery Care

Funded Projects Search


Project Number: R40MC26810
Grantee: Oregon State University
Department/Center: Epidemiology/College Public Health & Human Science
Project Date: 04/01/2014
Principal Investigator: Marit L Bovbjerg

Final Report



  • Women/Maternal
  • Prenatal
  • Perinatal/Infancy (0-12 months)


This project will explore midwifery care and planned out-of-hospital (i.e., home or birth center) birth in the US. Out-of-hospital birth in the US has increased by more than 40% in the last decade; safety of this practice for low-risk pregnant women within the context of the US healthcare system has been confirmed by two large, recent studies.2,3 However, one gap remaining in the literature involves identifying who, exactly, is "low risk"--that is, identifying which women are good candidates for midwife-attended home or birth center birth. The proposed project will combine two existing, national pregnancy registries: the Midwives Alliance of North America Statistics Project (MANA Stats), which focuses on home births; and the American Association of Birth Centers' Perinatal Data Project (PDR), which focuses on birth center births. Our first Aim will focus on transfers of care to hospital-based obstetricians. Midwives are primary care providers--when complications arise, they transfer care to obstetric specialists. Based on data presented in the Stapleton and Cheyney papers, 10-15% of women laboring at home or in a birth center in the US transfer care to a hospital-based provider during labor, and an additional 2-3% transfer immediately postpartum for either a maternal or neonatal indication. For Aim 1, we will use a random 2/3 of the combined MANA Stats/PDR dataset to develop and refine a predictive model for transfers, with the goal of identifying "risk factors" for transfer of care. With over 25,000 total births, the combined MANA Stats/PDR dataset will have sufficient power to detect small effects on the probability of intrapartum, postpartum (maternal), or neonatal transfers of care. Following standard practice for development of predictive models, we will then test the model using the remaining 1/3 of the data. The final model can then be used to inform clinical care and patient decision making. Our second Aim will also use the combined MANA Stats/PDR dataset, and will explore outcomes among the traditionally higher-risk groups of advanced maternal age and pre-gravid overweight. For a comparison (hospital birthing) group, we will create a matched cohort using the publically-available natality (birth certificate) file from the CDC. Our hypothesis is that out-of-hospital midwifery care modifies the previously-reported detrimental effects of advanced maternal age. Outcomes for this analysis include gestational diabetes, cesarean, NICU admission, birthweight, and others. As a whole, our project will inform clinicians, policy makers, insurers, and consumers about best practices for home and birth center birth within the unique context of the US healthcare system. This project relates to HRSA strategic research issues III and IV; as well as


Listed is descending order by year published.

Bovbjerg ML, Cheyney M, Brown J, Cox KJ, Leeman L. Perspectives on risk: Assessment of risk profiles and outcomes among women planning community birth in the United States. Birth. 2017 Mar 22. doi: 10.1111/birt.12288. [Epub ahead of print] PubMed PMID: 28332220.

Cheyney M, Bovbjerg ML, Burcher P. Home birth is unsafe, AGAINST: safe for whom? [invited commentary] British Journal of Obstetrics and Gynecology, 2015 Aug; 122(9): 1235.


Pregnancy, Primary Care, Postpartum, Labor & Delivery, Cesarean, Clinical Practice, Health Care Utilization, Perinatal

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