Determinants of high birth weight by geographic region in Canada.

This study aims to analyze the determinants of high birth weight (> 4000 grams) by various geographic regions of Canada. Analyses were performed using the data from cycles 1 to 4 (1994-2001; N=20,002 children) of the Canadian National Longitudinal Survey of Children and Youth (NLSCY). Children were grouped into five geographic residential area categories: the Atlantic provinces, Quebec, Ontario, the Prairie provinces and British Columbia. Determinants analyzed in the study include sex, gestational age and birth rank of children; maternal age and education; maternal smoking during pregnancy; family type; family socioeconomic status (SES) and maternal health (postpartum depression; hypertension and prescription drug use during pregnancy). In comparison to Quebec, the odds of giving birth to a high-birth-weight child were 25 percent higher in Ontario, 41 percent higher in the Atlantic provinces and 53 percent higher in British Columbia. In Quebec, non-smoking mothers of higher SES had increased odds of delivering a baby weighing more than 4000 grams, while in British Columbia, the odds of having a birth weight greater than 4000 grams doubled for children of non-smoking mothers from the lowest SES quintiles. The relationship between social disparities and macrosomia was found to vary by geographic region.