Table of Contents
ISRN Obstetrics and Gynecology
Volume 2011, Article ID 719675, 8 pages
Research Article

Interpretation of Controversial Teratogenic Findings of Drugs Such As Phenobarbital

1Foundation for the Community Control of Hereditary Diseases, Budapest 1026, Hungary
2Second Department of Obstetrics and Gynecology, School of Medicine, Semmelweis University, Budapest 1085, Hungary

Received 16 April 2011; Accepted 21 June 2011

Academic Editor: H. C. Wallenburg

Copyright © 2011 Andrew E. Czeizel et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Objective. To check the debated association between phenobarbital treatment during pregnancy and risk for congenital abnormalities (CAs) in their children. Study Design. It is a comparison of phenobarbital treatment in the mothers of cases with CA and matched controls without CAs in the Hungarian Case-Control Surveillance System of Congenital Abnormalities. Results. Of 22,843 cases with CA, 149 (0.65%) had mothers with phenobarbital treatment, while of 38,151 control newborn infants without CA, 209 (0.55%) were born to mothers with phenobarbital treatment (100–400 mg daily) (OR with 95% CI : 1.3, 1.1–1.7). Of 16 CA groups, only hypospadias had a higher risk after phenobarbital treatment in the critical period of this CA (OR with 95% CI : 2.4, 1.1–5.4). However, if only medically recorded phenobarbital treatments were evaluated and multiple testing bias was considered, this association would disappear. Conclusions. This study stresses the importance of the exclusion of recall bias and multiple testing bias.