High Dose Cholecalciferol to Reduce the Incidence of Gestational Diabetes in High Risk Pregnant Women

Determine the effect of increased vitamin D supplementation (4000 IU vitamin D3 +prenatal
vitamin) on the incidence of gestational diabetes compared to a standard prenatal vitamin
among pregnant women at high risk for gestational diabetes.

Explore the effect of increased vitamin D supplementation (4000 IU daily + prenatal vitamin),
compared to a standard prenatal vitamin, on glycemic control, need for oral hypoglycemic
agents and/or insulin, and delivery outcomes among the subset of women who develop
gestational diabetes.

Inclusion Criteria:

1. Women who are currently pregnant and receiving prenatal care at the Women's Health
Specialists Clinic (University of Minnesota Physicians) from either MD/DO or CNM
providers

2. Subject established prenatal care no later than the completed 12th week of gestation
(12 6/7 weeks)

3. Subject possesses as least one of the following characteristics:

1. BMI greater than or equal to 30 kg/m2

2. History of gestational diabetes in a prior pregnancy

3. History of infant with birth weight of 4500g or greater

4. Subject is capable of giving informed consent

Exclusion Criteria:

1. Age less than 18 years

2. Multiple gestation pregnancies (twins, triplets or greater multiples)

3. Vitamin D deficiency (defined as less than 20 ng/mL)

4. Preexisting diabetes mellitus defined as either:

1. pre-existing diagnosis prior to current pregnancy

2. failure of three-hour glucose tolerance test in first trimester of pregnancy