Assessment of Hypervitaminosis D during the first trimester of pregnancy on the mouse embryo. Preliminary report.

The effect of hypervitaminosis were studied in pregnant mice during 0-3 and 4-7 days of gestation. After pregnancy was determined, mothers received 50 000 I.U. of vitamin D2 during the first gestational period. During the first half of the first trimester, the vitamin D treatment did not significantly influence maternal weight, fetal weight, implantation rate and survival of the embryo. The number of mothers with malformed fetuses significantly increased during critical treatment periods (from 4-7 days of pregnancy.