Phenolphthalein treatment in pregnant women and congenital abnormalities in their offspring: A population-based case-control study.

Phenolphthalein is frequently used laxative drug since 1930s, but the possible teratogenic effect of phenolphthalein was not checked in casecontrol eptedmiological study. In addition US Food and Drug Administration (FDA) declared the mutagenic and carcinogenic effect of phenolphthalein in 1999, thus we decided to evaluate the birth outcomes particularly congenital abnormalities (CAs) of newborn infants born to women treated with phenolphthalein during pregnancy. Cases with CA and their matched controls without CA born to mothers with phenolphthalein use during pregnancy were compared in the population-based large data set of the Hungarian Case-Control Surveillance System of Congenital Abnormalities. Of 22,843 cases with CA, 191 (0.83%) while of 38,151 controls, 247 (0.64%) were born to mothers with phenolphthalein treatment (adjusted OR with 95% CI: 1.3, 1.0-1.5). The mean gestational week at delivery was somewhat longer in both the case (0.3 week) and control (0.2 week) groups while the mean birth weight was somewhat larger in cases (46 g) and controls (12 g) born to mothers with phenolphthalein treatment during the study pregnancy compared with mothers without phenolphthalein treatment. These differences were in agreement with the lower rate of preterm births and low birth weight in controls born to mothers with phenolphthalein treatment during pregnancy. The detailed analysis of different CA groups showed an association between maternal phenolphthalein treatment during pregnancy and a higher risk for Hirschsprung's disease (p = 0.01) based on 4 cases in the so-called other isolated CA-group. In conclusion phenolphthalein treatment in pregnant women associates with a higher risk for Hirschsprung's disease in their children, but this finding is only a signal which needs confirmation or rejection in other studies.