evaluation of vitamin d requirements during pregnancy

Conditions: Vitamin D Deficiency

Summary: the purpose of this study is to determine the effectiveness of vitamin d supplementation during pregnancy starting at the beginning of the second trimester. mothers will be randomized to one of three vitamin d dosing groups: 400, 2,000 or 4,000 international units per day. it is hypothesized that the highest dosing regimen will result in a better vitamin d status of women regardless of their ethnicity or race.

the prevalence of hypovitaminosis d in reproductive aged african-american women occurs at a rate of \> 40%. two factors have contributed to this public health problem: an inadequate dri for vitamin d and avoidance of sun exposure/use of sunscreen. this startling rate of hypovitaminosis d requires that the dri for vitamin d in pregnancy be evaluated in a detailed manner. the cochrane library (2002) released a report stating that there is insufficient data to evaluate the effects of vitamin d supplementation during pregnancy. recently, the safety of prolonged supplementation with up to 25x's dri (10,000 iu/day) was demonstrated in nonpregnant adults. it is essential to determine what dose of vitamin d is required to eliminate hypovitaminosis d during pregnancy and provide the fetus/neonate with adequate vitamin d stores during development and growth, particularly in darkly pigmented individuals. the aim of this research proposal, then, is to determine the efficacy, effectiveness, and safety of maternal vitamin d supplementation (as a function of ethnicity and uv exposure) in the prevention of hypovitaminosis d in the pregnant mother and her fetus/neonate. we hypothesize that darkly pigmented mothers will require substantially higher oral supplementation with vitamin d to eliminate hypovitaminosis d as compared to their caucasian counterparts. we propose a comprehensive clinical trial to test our hypothesis. mothers at 12 weeks' gestation will be randomized to one of three vitamin d treatment groups: 1. control, 400-, 2. 2,000-, or 3. 4,000 iu/day to be continued throughout pregnancy. calcium and vitamin d homeostasis and skeletal remodeling in the mother will be monitored closely throughout the pregnancy. bone density of the mother will be measured at 12 weeks' gestation and one-month postpartum. follow-up growth and skeletal integrity assessments of the infant will be performed at birth, 1, 6 and 12 months stratified by infant feeding regime. through these proposed studies, the prevalence of hypovitaminosis d among mothers, their developing fetuses and neonates, and the utility of maternal therapeutic intervention with vitamin d for both mother and fetus/infant will be assessed.

Eligibility criteria:
inclusion criteria: 1. women who are within the ages of 16-45 years 2. in good general health 3. less than 12 weeks pregnant (based on last menstrual period) exclusion criteria: 1. mothers with preexisting type i or type ii diabetes 2. mothers with preexisting hypertension 3. mothers with preexisting parathyroid disease or uncontrolled thyroid disease 4. mothers with multiple fetuses (e.g., twins, triplets, etc.)

Keywords: vitamin d cholecalciferol pregnancy bone mineral density