Disturbance of Pregnancy in Mouse and Rat by Systemic Antihistaminic Treatment

Abstract

Subcutaneous injections of antihistamines, Benadryl (2-(benzhydryloxy)-N,N-dimethyle-thylamine hydrochloride) into 95 female mice, and Pyrrolazote (10-[2-(l-pyrrolidyl) ethyl]-phenothiozine hydrochloride) into 44 female rats significantly reduced the number of normal litters. The antihistamines acted on the developing embryo after implantation had occurred. Failure of the antihistamine to inhibit decidual formation following systemic injection, while being effective intraluminally in inhibiting artificial deciduoma, is assigned to the failure of an adequate amount of the drug to reach the uterus.