孕妇应用某些药物可引致对胎儿的不良影响。但由于干扰胚胎发育的因素很多,动物实验也不能完全肯定,故孕妇用药对胎儿的影响尚待进一步研究之中。目前已知,绝大多数药物只要达到一定浓度时,都可以通过胎盘到达胎儿体内。药物可以无变化地通过胎盘,对母体及胎儿产生同样效果,如巴比妥类,药物也能够在母体与胎儿体内形成代谢产物而有毒性作用,如甾体激素类药物还能改变母体的生理状态,改变子宫内环境.不利于胎儿生长发 Pregnant women using certain drugs can cause adverse effects on the fetus. However, due to many factors that interfere with embryonic development, animal experiments can not be completely sure, so pregnant women on the fetus medication remains to be further studied. It is known that most drugs reach the fetus through the placenta when they reach a certain concentration. Drugs can pass unchanged through the placenta, the same effect on the mother and the fetus, such as barbiturates, drugs can also be formed in the maternal and fetal body metabolites and toxic effects, such as steroid hormones can change the physical mother Status, change the uterine environment is not conducive to fetal growth