Although there is no evidence to suggest that exposure to Diphenhydramine during pregnancy is related to major malformations, there were slight suggestions of an association between Diphenhydramine use and inguinal hernia or genitourinary malformations. Accordingly, Diphenhydramine is considered to be contraindicated during pregnancy.
Diphenhydramine is excreted into human breast milk but levels have not been reported. Although the levels are not thought to be high, the drug is considered to be contraindicated during lactation.