〔Abstract〕 Objective To explore the mechanism of maternal vitamin D deficiency(VDD)-induced fetal intrauterine growth restriction( IUGR) during pregnancy. Methods Four weeks female CD-1 mice were divided into two groups: control mice( CTRL) and vitamin D deficiency mice( VDD). VDD mice were fed with diet with low concentration of vitamin D and mated with normal male mice. Several pregnant mice were killed on gestational sixteenth day,and the placentas,serum of maternal and fetal mice were collected. Proteins of placental key enzymes of steroid hormone synthesis and signaling pathways of oxidative stress were measured using Western blot. Serum estrogen,progesterone and 25-( OH)-D were measured via radioimmunoassay. The remaining pregnant mice were killed. Placentas and fetus were weighted,fetus height and placental diameter were calculated. The pregnancy outcomes were observed. Results Diet with low concentration of vitamin D were used and VDD mice model were established after five weeks. Maternal VDD during pregnancy decreased the weight of placenta and fetus,reduced the height of fetus and the diameter of placentas. The expression of placental aromatase cytochrome p450( CYP19) and the level of estrogen were increased in VDD pregnant mice. Besides,maternal VDD during pregnancy increased the expressions of placental heme oxygenase 1( HO-1),NADPH oxidase 4( NOX-4) and 3-nitrotyrosine( 3-NT).VDD promoted placental nuclear factor E2-related factor 2( Nrf-2) nuclear translocation. Conclusion Maternal vitamin D deficiency during pregnancy causes IUGR partially through evoking placental oxidative stress and promoting estrogen synthesis.