Anthelmintic medication with focus on first-trimester exposure: an evaluation of pregnancy outcomes based on the Embryotox cohort.

The present study aims to contribute to the available experience on the systemic use of five different anthelmintics during pregnancy (albendazole, mebendazole, praziquantel, pyrantel and pyrvinium). Particular focus was placed on the occurrence of major birth defects and pregnancy loss following first-trimester exposure. As the assessed agents differ considerably in terms of their chemical structure and mechanism of action, they were analyzed separately. A total of 282 pregnancies with exposure to the study medication were recorded in the Embryotox database (January 1, 2000-February 28, 2023) and analyzed descriptively. Among 75 live-born infants with first-trimester exposure to mebendazole, five major malformations were reported, three of which were heart defects. Of the 21 live-born infants exposed to pyrantel in the first trimester, two were affected by aplasia cutis congenita of the scalp, one of whom was co-exposed to thiamazole. Among 47 live-born children with first-trimester pyrvinium exposure, one major birth defect was reported. No major malformations were observed among 4 and 10 live-born children exposed to praziquantel and albendazole, respectively. Given the limitations, the findings should be interpreted as descriptive observations and possible signals only. Further investigations with larger cohorts are required.