The safety of dextromethorphan in pregnancy : results of a controlled study

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.

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).

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.

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%.