ROCKVILLE, Md. (AP) _ The Food and Drug Administration is taking yet another look at whether an injectable contraceptive that provides three months of birth control is scientifically linked to breast, liver, or cervical cancer.

''Should we or could we now blow away the cloud of controversy that has engulfed this drug for the past 20 years?'' asked Dr. Ridgely Bennett, medical officer of the FDA.

The agency's Fertility and Maternal Health Drugs Advisory Committee on Friday considered Upjohn Co.'s request that it approve Depo-Provera for use as a contraceptive.

It is approved for use in the U.S. to treat endometrial and renal cancers, and because it is an approved drug, some doctors do prescribe it now for use as a contraceptive. But because it is outside the labeled use, those doctors open themselves to some legal liability.

An Upjohn vice president, Dr. Joann L. Data, told the committee that the company's studies found that one of the side effects of the drug is weight gain. She said generally the weight gain does not go beyond 15 pounds, but occurs in 60 percent of the women using the drug and increases with time.

Depo-Provera, known generically as depot-medroxyprogesterone acetate, or DMPA, also has been the subject of legal controversy because it could be used for so-called ''chemical castration'' sentences that judges have considered imposing on sex offenders.

Since the late 1960s, the drug's use as a contraceptive in this country has bounced back and forth between approval and a ban, based largely on animal studies that suggest a link to cancers of the cervix, liver and breast.

More recent studies, though, have indicated that the link may not be as strong as previously believed.

Results of a study on breast cancer, conducted in Kenya, Mexico and Thailand, found no increased risk among women who used the drug for more than five years.

''Both our investigation and the New Zealand study provide some reassurance that women who have used DMPA for a long time and who initiated use many years previously are not at increased risk of breast cancer,'' the researchers wrote in an article published in the British medical journal, The Lancet, last October.

But Dr. Samuel Shapiro, a professor at the Boston University School of Medicine, said that while he believed the FDA should approve the drug for use as a contraceptive, he is unconvinced that the breast cancer risk has been put to rest.

''There are grounds to suspect that the associations (with breast cancer) may be wholly or partly due to bias or to limited numbers,'' Shapiro told the panel. However, it also possible that recent or current use may be associated with breast cancer occurring at an early age.

The manufacturer says Depo-Provera currently is used as a contraceptive in 90 countries, including the United Kingdom, Germany, New Zealand, Norway, Belgium, Sweden and France.

The advisory panel's findings are not binding, but the FDA usually follows the advice of such panels.