Vitamin D in Pregnancy and Lactation
Vitamin D in Pregnancy and Lactation
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.
Inclusion Criteria:

 -  Women between 18-42 years of age

 -  within 18 plus/minus 3 weeks gestation

 -  planning to breastfeed their infant

 -  a singleton pregnancy

 Exclusion Criteria:

 -  Any co-morbid condition such pre-gestational diabetes, TB, cardiac or renal disease,
 HIV/AIDS, chronic hypertension, inflammatory bowel disease, autoimmune disease, liver
 disease, or epilepsy; conditions associated with vitamin D malabsorption: celiac
 disease, gastric bypass;

 -  History of previous adverse pregnancy outcome [preterm delivery <37; weeks GA,
 stillbirth, severe pre-eclampsia, eclampsia, HELLP syndrome (hemolytic anemia,
 elevated liver enzymes, and low platelet count)];

 -  Women will also be ineligible if they are taking more than 10 µg day supplemental
 vitamin D or drugs known to interfere with vitamin D metabolism (i.e corticosteroids).