 Subsequently for the next five days, women will collect three urine specimens daily. Women will then receive vitamin D to treat vitamin D deficiency. Once vitamin D repletion is accomplished, all women will repeat their 24-hour visit and subsequent five-day urine collections. Women will maintain vitamin D repletion by taking a twice monthly tablet 50,000 IU of vitamin D2. To confirm vitamin D repletion and safety over the full one year study, additional study visits will occur at 3, 6 and 12 months. 