Administration of interferon-alpha during pregnancy: effects on fetus

Interferon-alpha (IF alpha) is used for the treatment of myeloproliferative diseases and chronic viral illnesses. Because the agent has antiproliferat ive activity, its effects on a fetus are a concern. We encountered a 40-yea r-old Japanese woman who inadvertently received IF alpha during pregnancy f or the treatment of HCV hepatitis. The patient received 5 million units of IF alpha 2 to 4 times per week (total dose of 315 million units) between 13 and 33 weeks gestation. The patient delivered a normally formed healthy ma le infant, weighing 2,252 g at 37 weeks of gestation. The infant at 20-mont h-old exhibited normal growth and neurological development when last examin ed. Litera- tures were reviewed to determine the effects of IF alpha on the fetus. There have been 27 infants born to 26 mothers, including the presen t case, who were exposed to IF alpha in utero. Six women (23 %) were admini stered IFa inadvertently during pregnancy Four women (15%) gave birth prema turely. Although 6 infants (22 %) were affected by intrauterine growth reta rdation (IUGR), then were no IF alpha -related malformed infants. These res ults suggested that an inadvertent administration of IF alpha during pregna ncy may occur, but in that case IF alpha may not induce congenital malforma tions. These findings may encourage such women to continue pregnancy.