Introduction: Prenatal medical risk can be defined as one or more physical health issues or biological factors that predate or arise during pregnancy which heighten the risk of adverse perinatal outcomes, and often warrant specialized care from an obstetrician. The influence of the nature and magnitude of prenatal medical risk on breastfeeding outcomes remains poorly understood. Our objective was to determine the association between prenatal medical risk and breastfeeding duration from birth to 1 year.
Methods: We analysed data from the All Our Families longitudinal cohort (n=2,706). The exposure was prenatal medical risk, measured by the Antepartum Risk Tool of 46 physical and biological risk factors, and operationalized as one overall integer score of risk severity (sum of all present factors) and four dichotomous risk types capturing the presence of ≥1 factors pertaining to pre-pregnancy characteristics, past obstetrical problems, current obstetrical problems, and substance use. The outcome was breastfeeding duration in weeks. We calculated hazard ratios (HR) using Cox regression with censoring at 52 weeks or attrition, adjusting for potential demographic and obstetric confounders.
Results: Prenatal medical risk severity was associated with earlier breastfeeding cessation, with an HR of 1.05 per unit increase in severity score (95% CI=1.02-1.08). Shorter time to breastfeeding cessation was significantly associated with current obstetrical (HR=1.28, 95% CI=1.12-1.46) and substance use (HR=1.82, 95% CI=1.45-2.29) risk types, but not pre-pregnancy (HR=1.10, 95% CI=0.97-1.24) or past obstetrical (HR=1.06, 95% CI=0.89-1.25) risk types. Effect sizes and significance were unchanged following adjustment for confounders.
Conclusion: Prenatal medical risk severity and certain types of medical risk may negatively impact a woman’s breastfeeding duration on average, even after accounting for her sociodemographic background and labour outcomes. Future research should explore biological and psychosocial reasons for this disparity to ensure that women with prenatal medical risk receive appropriate breastfeeding support.
Amy Metcalfe– Associate Professor, Department of Obstetrics and Gynecology, University of Calgary, Calgary, AB
Alberto Nettel-Aguirre– Associate Professor, Department of Paediatrics, University of Calgary, Calgary, AB
Suzanne Tough– Professor, Department of Paediatrics, University of Calgary, Calgary, AB
Katie Chaput– Assistant Professor, Department of Obstetrics and Gynecology, University of Calgary, Calgary, AB