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Reduced prevalence of small-for-gestational-age and preterm birth for women of low socioeconomic position: a population-based cohort study comparing antenatal midwifery and physician models of care
  1. Daphne N McRae1,
  2. Patricia A Janssen1,
  3. Saraswathi Vedam2,
  4. Maureen Mayhew1,
  5. Deborah Mpofu3,4,
  6. Ulrich Teucher5,
  7. Nazeem Muhajarine4
  1. 1 School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada
  2. 2 Birth Place Lab, Department of Family Practice, University of British Columbia, Vancouver, British Columbia, Canada
  3. 3 Saskatoon City Hospital, Saskatoon Health Region, Saskatoon, Saskatchewan, Canada
  4. 4 Department of Community Health and Epidemiology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
  5. 5 Department of Psychology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
  1. Correspondence to Dr Daphne N McRae; daphne.mcrae{at}


Objective Our aim was to investigate if antenatal midwifery care was associated with lower odds of small-for-gestational-age (SGA) birth, preterm birth (PTB) or low birth weight (LBW) compared with general practitioner (GP) or obstetrician (OB) models of care for women of low socioeconomic position.

Setting This population-level, retrospective cohort study used province-wide maternity, medical billing and demographic data from British Columbia, Canada.

Participants Our study included 57 872 pregnant women, with low socioeconomic position, who: were residents of British Columbia, Canada, carried a singleton fetus, had low to moderate medical/obstetric risk, delivered between 2005 and 2012 and received medical insurance premium assistance.

Primary and secondary outcome measures We report rates, adjusted ORs (aOR), and 95% CIs for the primary outcome, SGA birth (<the 10th percentile), and secondary outcomes, PTB (<37 weeks’ completed gestation) and LBW (<2500 g).

Results Our sample included 4705 midwifery patients, 45 114 GP patients and 8053 OB patients. Odds of SGA birth were reduced for patients receiving antenatal midwifery versus GP (aOR 0.71, 95% CI 0.62 to 0.82) or OB care (aOR 0.59, 95% CI 0.50 to 0.69). Odds of PTB were lower for antenatal midwifery versus GP (aOR 0.74, 95% CI 0.63 to 0.86) or OB patients (aOR 0.53, 95% CI 0.45 to 0.62). Odds of LBW were reduced for midwifery versus GP (aOR 0.66, 95% CI 0.53 to 0.82) or OB patients (aOR 0.43, 95% CI 0.34 to 0.54).

Conclusion Antenatal midwifery care in British Columbia, Canada, was associated with lower odds of SGA birth, PTB and LBW, for women of low socioeconomic position, compared with physician models of care. Results support the development of policy to ensure antenatal midwifery care is available and accessible for women of low socioeconomic position. Future research is needed to determine the underlying mechanisms linking midwifery care to better birth outcomes for women of low socioeconomic position.

  • midwifery
  • socioeconomic status
  • birth outcomes
  • quality in healthcare
  • fetal medicine
  • maternal medicine

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  • Contributors DNM designed the study, conducted the statistical analyses, interpreted the results, drafted the initial manuscript and revised subsequent drafts. NM and PAJ designed the study, reviewed the statistical analyses and interpreted the results. SV, MM and DM contributed to study design and clinical interpretation. UT contributed to interpretation. NM, PAJ, SV, MM, DM and UT reviewed and revised the manuscript. All authors approved the final manuscript.

  • Funding DNM was supported by an Arthur Smyth Scholarship from the College of Medicine, and a PhD Scholarship from the Department of Community Health and Epidemiology, University of Saskatchewan, Saskatoon, SK, Canada. PAJ is supported by a Senior Scholar salary award from the BC Children’s Hospital Research Institute, Vancouver, BC, Canada.

  • Disclaimer All inferences, opinions and conclusions drawn in this study are those of the authors, and do not reflect the opinions or policies of the Data Stewards. Funding sources had no involvement in the study; the authors are independent of all funders.

  • Competing interests As of May 2018, DNM has been providing consulting services to the Midwives Association of BC. No other authors have competing interests to declare.

  • Patient consent Not required.

  • Ethics approval University of Saskatchewan, Biomedical Research Ethics Board (registration numbers 00001471 and 00008358) and the University of British Columbia, Children’s and Women’s Health Center of BC Research Ethics Board (registration number H14-01629).

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement No additional data available.

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