Vitamin D Treatment and Hypocalcemic Pregnant Women

* Pregnant women in 24-26 gestational week will be recruited.Serum calcium and 25(OH)D will be evaluated and women with mild hypocalcemia (serum calcium 8-8.6 mg/dl) and 25(OH)D less than 30ng/ml will be entered to study. . * Excluding criteria are: gestational diabetes or diabetes before pregnancy, severe preeclampsia, chronic hypertension, fetal anomaly, oligohydramnios or polyhydramnios, parathyroid disorders, hepatic or renal diseases, malnutrition , use of anti- convulsive and immunosuppressive drugs. * Participants will randomly assigned in to two groups of intervention and control groups .Randomization will be done by random number generator. Intervention group will receive weekly vitamin D3, 50,000 unit for 8 weeks plus daily prenatal multivitamin containing elemental calcium 250 mg/day and vitamin D3 400 unit , control group will receive daily prenatal multivitamin. * At the time of delivery, serum calcium, 25(OH)D of mothers, maternal weight gain during study , Serum calcium and 25(OH)D of newborns and neonatal growth indices ( length, weight, head circumference ) will be compared between two groups.