The safety of dextromethorphan in pregnancy - Results of a controlled study

Background: Dextromethorphan (DM), the d-isomer of the codeine analog levor phanol, is an active ingredient present in a variety of cough and cold reme dies. Recently, data generated from a study in chick embryos were extrapola ted to suggest that pregnant women should not use this drug because of the risk of birth defects. We conducted a controlled study of pregnant women wh o used DM, to examine the possible teratogenic risk in humans. Materials and methods: We followed up women who used DM and had been counse led by the Motherisk Program during their pregnancy. A control group of wom en was matched for age, smoking, alcohol use, and disease state (upper resp iratory tract infection, not treated with DM). Results: We were able to ascertain pregnancy outcome in 184 women. There we re 172 live births, 10 spontaneous abortions, 1 therapeutic abortion, and 1 stillbirth. One hundred twenty-eight of the women used the drug during the first trimester of pregnancy. There were three major malformations (2.3%) among the babies of women who used DM in die first trimester, seven minor m alformations, and the mean (+/- SD) birth weight was 3,381 +/- 670 g. In th e control group, there were 17 live births, 8 spontaneous abortions, and 2 therapeutic abortions. There were five major malformations, one of which wa s a chromosomal abnormality (2.8%), eight minor malformations, and the mean birth weight was 3,446 +/- 571 g. Conclusion: This study fails to show that DM use during pregnancy increases the rates of major malformations above the expected baseline rate of 1% to 3%.