Use of antibiotics during pregnancy.

OBJECTIVE: To describe the occurrence and distribution of antibiotic treatments, in addition their indications in control pregnant women in the population-based large dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980-1996.
RESULTS: Of 38 151 control pregnant women who delivered later newborn infants without congenital abnormality, 6554 (17.2%) were treated by antibiotics. Most women (14.5%) had penicillin, while 1.2% and 0.7% of pregnant women were treated by cephalosporins and tetracyclines, respectively. More than 100 pregnant women used the following antibiotics: ampicillin (6.9%), penamecillin (5.9%), cefalexin (1.0%), phenoxymethylpenicillin (0.6%), oxytetracycline (0.5%), erythromycin (0.45%), benzylpenicillin-procain (0.4%) and benzylpenicillin+benzylpenicillin-procain (0.3%). Different antibiotics had different indications for treatment. The mean birth weight was significantly lower in the treated group compared to the untreated group. PRACTICAL IMPLICATIONS: Different antibiotics have different chemical structures and indications for treatment. Therefore it is not appropriate to evaluate their teratogenic potential of combined antibiotic groups. There may be many interactions between underlying maternal diseases, other drug uses, further confounding factors and antibiotics studied, thus adequate controls are needed to estimate the adjusted teratogenic odds-risk ratios. European countries have different spectrum of antibiotic use. It would be necessary to know these baseline data of different populations. The anxiety and fear created by the notion that nearly all drugs cause congenital abnormalities may be more harmful than some proven human teratogenic drugs themselves. Thus a better risk-benefit estimation for antibiotic uses during pregnancy is an urgent and important task.