PHILADELPHIA -- When used in pharmacologic doses, interferon-[alpha] is not associated with a higher incidence of fetal malformations or adverse pregnancy outcomes, according to a review of 35 case reports presented at the annual meeting of the American College of Obstetricians and Gynecologists.
Interferon-[alpha] (IFN-[alpha]) carries a category C designation, which means its safety in pregnancy has not been established.
"[IFN-[alpha]] has been effective in reducing hepatitis C RNA in the nonpregnant adult population. However, its safety in pregnancy has been questioned, and it has never been studied in a clinical trial," Dr. Jacquelyn Jai Pelham said.
"To shed some light on the subject, I combined case reports and reported the overall pregnancy outcomes ... using all the published information we have on pregnancy outcome and interferon use," said Dr. Pelham of Jefferson Medical College, Philadelphia.
She searched Medline and found 35 pregnancies with 36 fetuses exposed to IFN-[alpha]. The mean maternal age was 30 years. Treatment indications were essential thrombocythemia (46%), chronic myelogenous leukemia (29%), hepatitis C (11%), hairy cell leukemia (6%), Hodgkin's lymphoma (3%), multiple myeloma (3%), and chronic demyelinating polyneuropathy (3%).
The average weekly dose among the 35 pregnancies was 14.7 million U, considered within the acceptable treatment range. Treatment was started in the first trimester in 24 pregnancies (69%).
The mean duration of treatment was 25 weeks, the mean estimated gestational age at delivery was 37 weeks, and the mean newborn weight was 3 kg.
Of the fetuses, 6 of 36 (17%) developed intrauterine growth restriction. Of those, four (67%) were in pregnancies complicated by essential thrombocythemia. "Essential thrombocythemia has been associated with intrauterine growth restriction," Dr. Pelham said.
Malformations were noted in 1 of the 36 fetuses (3%).
"[IFN-[alpha]] may be a promising tool to reduce [hepatitis C virus] RNA in HCV-positive pregnant women to potentially decrease the rate of vertical transmission," Dr. Pelham said.
Four million people in the United States are infected with the hepatitis C virus, and 75% are viremic. The virus is found in 0.6% of the pregnant population, Dr. Pelham said. The vertical transmission rate is proportional to the titer of HCV RNA, and there is no current therapy to reduce vertical transmission.
"There have been no clinical trials involving [IFN-[alpha]] and pregnancy, and many pharmaceutical companies and medical institutions are reluctant to perform such research, due to safety concerns," she said.
BY NICHOLAS MULCAHY
Contributing Writer
COPYRIGHT 2004 International Medical News Group
COPYRIGHT 2004 Gale Group
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