The aim of this retrospective study is to clarify the medical and statistical evaluation of the effects of antiepileptic medication when given during pregnancy. (1) There was no statistically significant higher incidence of malformations in 199 children of treated mothers in comparison with 394 children of untreated mothers. However, the statistiscal hypothesis that there is no relationship could not be confirmed. We found a statistically significant relationship in cases of hare lip and cleft palate. But this relationship is open to question on medical grounds. Even if there were a relationship, the risk must be small, since probably hitherto unknown additional factors play a role. Therefore, anti-epileptic medication during pregnancy is not contraindicated. (2) Just because of the small incidence of anomalies in children, the number of investigated children of treated and untreated mothers has to be enlarged to almost 1,850 to assess if there is any risk at all. (3) Poor labour pains and poor drinking of the new-born may be due to sedative and spasmolytic side effects. These results have to be completed by a study in prospect. (4) It is worthwhile differentiating teratogenic and mutagenic effects, because anti-epileptic medication is generally started long before pregnancy begins. Evaluating teratological effects, the incidence and type of anomalies of the children of treated mothers, and of children of fathers treated for some time before conception have to be compared.