Drug exposure in pregnant women.

The objectives of this paper are to describe the Hungarian case-control surveillance system of congenital abnormalities (HCCSCA), to summarize the principles of this activity and our main experiences. Among the main principles, the importance of the time factor (the first trimester concept is outdated), the differentiation of isolated and multiple manifestations of the seemingly same congenital abnormalities, noxa specificity, the separation of drugs and pregnancy supplements within medicinal products (or medicines) are stressed. After some methodological problems (recall bias, chance effect), the main experiences regarding the risk and benefit of medicines are summarized. The conclusion is that the results of our studies based on the data set of the HCCSCA showed that at present the exaggerated teratogenic risk of drugs is much more harmful for the fetus than the real teratogenic effect of some drugs themselves. Medical doctors and other experts therefore need more education to know the principles and findings of modern human teratology because it may help us to have a better balance between the risk and benefit of drug use during pregnancy.