Risk and Benefit of Drug Use During Pregnancy

International Journal of Medical Sciences

Ferenc Bánhidy,1 R.Brian Lowry,2 and Andrew E. Czeizel3
1 Second Department of Obstetrics and Gynecology, Semmelweis University, School of Medicine, Budapest, Hungary
2 Department of Medical Genetics, University of Calgary and Alberta, Children’s Hospital Calgary, Canada
3 Foundation for the Community Control of Hereditary Diseases, Budapest, Hungary
Corresponding address:
Dr. Andrew E.Czeizel, 1026 Budapest, Törökvész lejtő 32, Hungary. e-mail: czeizel@interware.hu
Conflict of interest: None declared.
Received May 1, 2005; Accepted June 3, 2005.


Environmental teratogenic factors (e.g. alcohol) are preventable. We focus our analysis on human teratogenic drugs which are not used frequently during pregnancy. The previous human teratogenic studies had serious methodological problems, e.g. the first trimester concept is outdated because environmental teratogens cannot induce congenital abnormalities in the first month of gestation. In addition, teratogens usually cause specific congenital abnormalities or syndromes. Finally, the importance of chemical structures, administrative routes and reasons for treatment at the evaluation of medicinal products was not considered. On the other hand, in the so-called case-control epidemiological studies in general recall bias was not limited. These biases explain that the teratogenic risk of drugs is exaggerated, while the benefit of medicine use during pregnancy is underestimated. Thus, a better balance is needed between the risk and benefit of drug treatments during pregnancy. Of course, we have to do our best to reduce the risk of teratogenic drugs as much as possible, however, it is worth stressing the preventive effect of drugs for maternal diseases (e.g. diabetes mellitus and hyperthermia) related congenital abnormalities.


Among environmental factors, dangerous lifestyle seems to be the greatest hazard for the development of the fetus due to the common practice of consuming alcohol and smoking tobacco. Alcohol may cause fetal alcohol syndrome or at least fetal alcohol effects 1,2. It is preventable by abstinence during pregnancy but often unavoidable because approximately 50% of pregnancies are unplanned and hence alcohol consumption occurs before a woman knows that she is pregnant. Recently the teratogenic potential of smoking has been shown in some congenital abnormalities (CAs), particularly terminal transverse type of limb deficiencies 3 and Poland sequence 4, while the gene-environmental interaction was shown in the origin of orofacial clefts 5. The role of teratogenic effect of environmental pollutants such as methyl mercury 6 was also reported but we cannot estimate the magnitude of this problem. The primary prevention of infectious diseases by vaccination is extremely important particularly in the prevention of CA-syndromes caused by rubella and varicella viruses. Here we focus on teratogenic medication and their prevention.


Author: Leslie Carol Botha

Author, publisher, radio talk show host and internationally recognized expert on women's hormone cycles. Social/political activist on Gardasil the HPV vaccine for adolescent girls. Co-author of "Understanding Your Mood, Mind and Hormone Cycle." Honorary advisory board member for the Foundation for the Study of Cycles and member of the Society for Menstrual Cycle Research.