4.3.8 Nutrient intake: Dietary and supplement intake by the mothers during the last trimester of pregnancy will be assessed using a validated food frequency questionnaire, the modified Willett/Harvard (60). This questionnaire is modified to assess intakes over the last 3 months of pregnancy. These data will be used to describe vitamin D exposure of the fetus in utero when bone is mineralizing. At each visit and while the mother is lactating, intake of vitamin D will be assessed using a 24-hour recall. The value for maternal vitamin D intake will be used to describe our population as necessary to determine if results can be extrapolated to the Canadian population.