Abstract: Objective：To apply the antioxidants（Vitamin C，Vitamin E，Salvia Miltiorrhiza L：SML） preventively to the pregnant women，to investigate the influence of using the antioxidants to the obstetrical complications，the conditions of delivery and perinatal. Methods：From April 2005 to July 2006，3 485 pregnant women from 24 national wide cooperative hospitals were involved in this prospective research project. The participants were randomly divided into two groups：1 607 cases included in antioxidant group with administration of vitamins and SML; 1 878 cases were in control group without any medicine given. Every participant was under monitoring for the pregnant complications，the delivery condition and perinatal condition. Results：①The incidence of membrane disorders，the fetal distress and amniotic fluid abnormalities in antioxidant group were lower than that in control group（P ＜0.01）.Nevertheless，there was no difference between two groups in the morbidity of GDM，PIH and ICP（P ＞0.05）. ②The average delivery week of antioxidant group and control group were 39.17w vs. 39.08w（P ＞0.05），and the average newborn weight of two group were 3 388.29 g vs. 3 374.81 g（P ＞0.05）. There was no difference in the incidence of premature labor，low-birth weight and giant babies between two groups（P ＞0.05）. ③The maternal mortality of anti-oxidant group and control group were 0 vs. 0.11%（P ＞0.05），and the perinatal mortality of two groups were 0.44% vs. 0.11%（P ＞0.05）. ④The newborn morbidity in antioxidant group were lower than control group（P ＜0.01），especially in newborn jaundice. Conclusions：There were no influence to the delivery weeks，the newborn weight，premature labor，low-birth weight of newborn，giant babies，the maternal and perenatal motality with using the antioxidants. Whereas，the antioxidants could give some help for preventing some obstetrical complications and newborn diseases，especially in the preventing PROM and newborn jaundice which effects were confirmed.

Key words: Antioxidants, Pregnancy outcome, Bstetric labor complications, Hypertension, pregnancy-induced, Diabetes