Oral phenoxymethylpenicillin treatment during pregnancy - Results of a population-based Hungarian case-control study

The objective of the study was to examine the human teratogenic potential o f oral penicillin V: phenoxymethylpenicillin treatment during pregnancy in the large population-based dataset of the Hungarian Case-Control Surveillan ce of Congenital Abnormalities, 1980-1996. The dataset included 22,865 preg nant women who had fetuses or newborns with congenital abnormalities and 38 ,151 matched pregnant women who had newborn infants without any congenital abnormality (population control group). Of 22,865 case pregnant women, 173 (0.8%) had phenoxymethylpenicillin treatments, while of 38,151 population c ontrols, 218 (0.6) were treated by this penicillin V (crude OR 1.3 with 95% CI: 1.1-1.6). This difference was explained mainly by recall bias and conf ounders because adjusted OR for medically documented phenoxymethylpenicilli n treatments did not show difference during the second-third months of gest ation, i.e. in the critical period for most major congenital abnormalities in case-matched control pairs. Thus, treatment with oral phenoxymethylpenic illin during pregnancy presents very little if any teratogenic risk to the fetus.