WASHINGTON (AP) -- A consumer group is again urging a ban of the prescription diet drug Meridia, saying at least 49 users have died of heart problems, including some in their 20s and 30s.

Also, the Food and Drug Administration has 54 reports of women who suffered stillbirths, miscarriages or had babies with birth defects while using Meridia, Public Citizen said Wednesday. Among them were four babies born with malformed hearts, similar to defects seen in some animal experiments with the drug.

Women are not supposed to diet during pregnancy, and the drug's label does not mention fetal harm if a woman becomes pregnant while taking Meridia. But Meridia does bear a warning that it can substantially raise some people's blood pressure, so users should be monitored and those with certain health problems should not take it.

Public Citizen's Dr. Sidney Wolfe said that warning is not enough. He said the FDA has received reports of 30 more Meridia users who died of heart attacks or cardiac arrest since he first petitioned the agency for a ban in March 2002.

"The number of victims is rising rapidly," Wolfe wrote FDA Commissioner Mark McClellan. "There is no justification in continuing to market a drug that provides minimal weight reduction while increasing the likelihood of injury and death."

FDA officials would not comment on Meridia's safety, saying only that they were evaluating Wolfe's petition.

Meridia manufacturer Abbott Laboratories called Wolfe's allegations irresponsible, saying recent re-examinations by European and Canadian regulators concluded the drug is safe.

Obesity itself puts people at serious risk of premature death from heart problems, Abbott noted.

Doctors voluntarily report possible side effects to the FDA, which monitors those reports for signs of drug risks. Filing a report does not prove a drug was to blame; conversely, the FDA says only a small fraction of side effects get reported.

An estimated 10 million people worldwide have used Meridia, which the FDA has called a "moderately effective" weight-loss aid for the obese.

Copyright 2003 The Associated Press. All rights reserved.