The study participants are vitamin D deficient females undergoing (intra-cytoplasmic sperm injection (ICSI) trial in the age of 20 to 35 years. Serum vitamin D will be assessed. Accordingly, if they are deficient in vitamin D, they will be eligible for the study.400 vitamin D deficient women will be randomly allocated to either one of two groups. The first group will receive vitamin D supplementation in addition to the routine care. The other group will receive the routine care only. The study will be conducted in the IVF unit of department of Obstetrics and Gynecology, Cairo University.