Background: Dextromethorphan (DM), the d-isomer of the codeine analog levorphanol, is an active ingredient present in a variety of cough and cold remedies. Recently, data generated from a study in chick embryos were extrapolated 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 who used DM, to examine the possible teratogenic risk in humans.
Materials and methods: We followed up women who used DM and had been counseled by the Motherisk Program during their pregnancy. A control group of women was matched for age, smoking, alcohol use, and disease state (upper respiratory tract infection, not treated with DM).
Results: We were able to ascertain pregnancy outcome in 184 women. There were 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 the first trimester, seven minor malformations, and the mean (+/- SD) birth weight was 3,381 +/- 670 g. In the control group, there were 174 live births, 8 spontaneous abortions, and 2 therapeutic abortions. There were five major malformations, one of which was 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%.