Pyridoxine/doxylamine - Safety in Pregnancy

Safety in Pregnancy

Due to the extensive scientific evidence demonstrating that there is no difference in the risk for birth defects or other adverse pregnancy outcomes between infants whose mothers take pyridoxine/doxylamine during pregnancy and those infants whose mothers do not take this drug combination, the two ingredients of the drug are considered Pregnancy Category A drugs.

Since the mid-1950s, over 33 million women have used the combination drug of pyridoxine/doxylamine in pregnancy, and scientific analysis on more than 200,000 exposed pregnancies has been conducted to determine if the combination of pyridoxine and doxylamine is harmful to the unborn baby. No epidemiological studies have found any teratogenic effect.

Two separate meta-analyses have been conducted that have assessed pregnancy outcomes following the use of a combination of pyridoxine and doxylamine with or without dicyclomine during the first trimester of pregnancy. The initial meta-analysis, published in 1988, combined data from 12 cohort and 5 case-control studies, and the subsequent meta-analysis, published in 1994, combined data from 16 cohort studies and 11 case control studies. These studies included over 200,000 Bendectin-exposed pregnancies and did not observe an increased risk for major malformations. Separate analyses were conducted for specific defects including cardiac defects, limb reduction defects, oral clefts, and genital tract malformations; no increased risks for these defects were found.

In 1989, a report on the safety of the drug combination of pyridoxine/doxylamine for use in the management of NVP was prepared by a panel of Canadian and American experts for the Special Advisory Committee on Reproductive Physiology to the Health Protection Branch of Health Canada (currently called the Health Products and Food Branch). These scientific experts concluded that “numerous studies in animals and in humans that have been reported in the scientific and medical literature demonstrate that Bendectin is not a teratogen…The safety of Bendectin/Diclectin in the management of nausea and vomiting of pregnancy has been established by its use in many thousands of pregnant women”.

A study was conducted to determine whether the combination drug of pyridoxine and doxylamine had an effect on the neurodevelopment of children exposed in utero. Results from this study observed no difference in intelligence quotient scores between children who were exposed to pyridoxine/doxylamine in utero and children who were not exposed.