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.