The contraceptive foams, jellies and creams used by at least 2 million American women may cause some birth defects, possibly more than twice the rate than for those who don't use them, a highly regarded drug study team said yesterday.

The study showed that 2.2 percent of the babies born to 793 women who used the contraceptives had physical deformities of some sort at birth compared with only 1 percent of the babies born to 3,902 women who didn't use them.

The conclusion is "tentative" and the subject needs more research, according to members of the Boston Collaborative Drug Project and other experts in this week's Journal of the American Medical Association.

Still, the finding raises a question about one of the few contraceptives about which almost no safety questions have been raised.

The data are still "thin" and inconclusive, Dr. Bruce Stadel, a specialist in contraceptive evaluation at the National Institutes of Health, commented. "The only action I'd recommend now is prudence. If a woman plans to become pregnant, she might discontinue using these products at least two weeks to a month before trying."

Dr. Herschel Jick of Boston University, head of the Boston drug project, said: "I'd say if a women is using these and there's any suggestion at all that she might be pregnant, she stop using them and get a pregnancy test. Many women get pregnant and continue using their contraceptive for months."

NIH funding of contraceptive research is about $8 million a year, which family planning groups consider grossly inadequate.

The contraceptives involved are sold both in forms used with a diaphragm and others used alone -- and widely used today without prescription. A 1976 survey indicated 1.6 million married women used one form or other. Drugstore sales have increased greatly since then, and many teen-agers buy foams to avoid pregnancy.

Jick collaborated with scientists at Harvard, Massachusetts General Hospital and the the Sidney Farber Cancer Institute for his study on patients of the Seattle Group Health Cooperative.