Vitamin D in Pregnancy and Lactation

Vitamin D Deficiency

Vitamin D, Infant, Lactation, Dose-Response

Background: Vitamin D is vital throughout pregnancy and lactation for both maternal and infant health. Health Canada recommends women take the AI of 5ug/day of vitamin D during pregnancy, however, it is unknown how much vitamin D is necessary to ensure both mother and baby reach a vitamin D serum concentration of 25OHD\>75nmol/L.

Purpose & Hypothesis: This project aims to determine maternal and infant responses vitamin D supplementation in pregnancy and lactation. It is hypothesized that the current AI of 5 μg of vitamin D will be inadequate for women and their infants in Canada to achieve optimal 25OHD concentrations (\> 75nmol/L). Methods: Healthy pregnant women between 18-42 years of age without history of pregnancy complications will be recruited for a double-blind, randomized, controlled trial where they will receive one of three different dosages of vitamin D (10, 25 and 50ug/day) as part of a standard prenatal vitamin. The study at 18 plus/minus 3 weeks gestation and will carry on throughout pregnancy and lactation. Mother and infant vitamin D levels in breast milk and blood will be measured at regular intervals. Skin colour will be measured via light reflectometry. Bone biomarkers such as plasma osteocalcin and urinary n-telopeptide will be assessed. Dietary vitamin D intake and sun exposure will be estimated using a food frequency and lifestyle questionnaire. Data will be analyzed using multiple regression analysis controlling for baseline values. Expected Results & Conclusions: It is expected that greater vitamin D intakes (25, 50ug/day) will be necessary to raise maternal and infant serum concentrations to 25OHD\>75nmol/L to avoid infant supplementation. This data will aid policy makers, mothers and healthcare workers in recommended and appropriate vitamin D dosage throughout pregnancy and lactation.

Canada