Grant: Doctoral: Vanier Canada Graduate Scholarships

A bigger than average baby (called macrosomia) is generally accepted as an adverse outcome in maternity care. About 10% of all babies in Canada are macrosomic. This is a significant public health concern as macrosomia has been linked to higher rates of cesarean or forceps delivery, severe birth trauma, excess bleeding, infant birth injury and infant death. Macrosomia is increasingly common worldwide, in part due to increases in obesity, excess weight gain and diabetes among childbearing women. A surprising recent finding indicated that 18% of all midwife-involved births in Ontario were macrosomic babies. Midwifery is a rapidly growing profession in Canada and outcomes are understudied. Reasons for these elevated rates of macrosomia among midwifery clients is unknown. Further, the impact of macrosomia on severe health outcomes is also unknown and it may differ for midwifery vs physician care. This study proposes to address this serious research gap by examining two cohorts of births in BC and WA state who were attended by midwives and physicians. The study findings will clarify the extent of macrosomia and associated severe outcomes among midwife v. physician births. Further, this will identify individual factors, aspects of prenatal or labor (adherence to specific obstetric guidelines from the Society of Gynecologists of Canada), or differences in training of midwives or gestational diabetes screening methods which could reduce severe morbidities among bigger babies and their mothers. Study findings can be used to propose evidence-based interventions, updated guidelines or policies to improve health for larger babies and reduce adverse outcomes such as cesarean delivery, birth trauma, or newborn birth injury.