Enoxaparin gets favorable labeling change.(Pregnant Women With Heart Valves)

A big upsurge in enoxaparin usage by obstetricians is highly unlikely, despite newly revised, less-prohibitive labeling for the low-molecular-weight heparin, Dr. Charles Lockwood predicted in an interview with this newspaper.

"Most hematologists and obstetricians I know who manage these sorts of high-risk pregnancies already use low-molecular-weight heparin," observed Dr. Lockwood, who is the Anita O'Keefe Young Professor and Chairman of Ob.Gyn. at Yale University, New Haven, and former chair of the American College of Obstetricians and Gynecologists Practice Affairs Committee.

Dr. Flavia Dietrich agreed that in obstetric circles the major effect of the softening of the package insert language will be greater peace of mind rather than markedly increased enoxaparin (Lovenox) usage.

"For physicians who were already using Lovenox in pregnant women for whatever reason, I think they'll feel more comfortable," said Dr. Dietrich, who is senior director of cardiovascular medicine and thrombosis for Aventis in Bridgewater, N.J.

Aventis' new Food and Drug Administration-approved product labeling for enoxaparin eliminates a previous warning stating that the drug "is not recommended" for pregnant patients who have mechanical heart valves, substituting instead the phrase "has not been adequately studied." The package insert now also includes for the first time reassuring data regarding the drug's lack of teratogenicity in a retrospective 600-patient study involving 693 live births in which enoxaparin was prescribed off label for the prevention of recurrent fetal loss.

The rate of major congenital anomalies was 2.5%--no different from the background rate.

"From the fetus's perspective, the story is over. I think it's very safe to say low-molecular-weight heparin is not teratogenic," Dr. Lockwood said.