The announcement last month by G.D. Searle & Co. that it is removing three types of intrauterine devices (IUDs) from the U.S. market has left the 1 million American women who use this form of contraception with a difficult decision about birth control.

"We have gone from the possibility of giving people choices as to when they want to become pregnant to, step by step, making it more difficult for them," said Dr. Mortimer Rosen, Chairman of Obstetrics and Gynecology at Columbia University's College of Physicians and Surgeons.

Searle announced it will end U.S. sales of the Cu-7, the TATUM-T and the Mark-7, not for medical or safety reasons, but because of "the escalating costs" of defending increasing numbers of "unwarranted" users' lawsuits. The decision comes after 15,000 women sued the A.H. Robbins Co. for damages suffered from using the Dalkon Shield, a design of IUD blamed for numerous cases of infection and sterility. The company has since filed for bankruptcy.

The only remaining IUD on the American market will be Progestasert, an IUD that contains the hormone progesterone. It is still manufactured by the Alza Corp., but many physicians said they expect this product will also be taken from the market.

Rosen and others predict that more women now will be forced to choose the pill, barrier methods such as condoms or diaphragms, or sterilization.

"If women are under 35, they can probably go on the pill," said Dr. Benny Waxman, professor of obstetrics and gynecology at George Washington University Medical School. "If they're over 35, it depends on family history, coronary profile and if they don't smoke." But women who cannot take hormones, including diabetics, heart patients and those who have had small blood clots, must avoid the pill.

First developed in the 1960s, IUDs are used by an estimated 60 million women worldwide, according to 1982 figures compiled by Johns Hopkins University's Population Reports. It is one of the most effective birth control methods available, ranking above the diaphragm, condom and foam, and the sponge. But IUD users face an increased risk of infection, which can later cause fertility problems. IUD users also face an increased risk of developing an ectopic, or tubal, pregnancy.

Studies suggest, however, that at least some of the increased infection associated with IUD use may be a problem of sexually transmitted diseases, since infection rates are very low in monogamous, married women who use IUDs.

"There was no medical reason to take the IUDs off the market," said Dr. Luella Klein, former president of American College of Obstetricians and Gynecology, adding that for many women -- particularly those over 35 -- this move deprives them of a good means of birth control.

In the meantime some doctors, including Dr. William Mixson of Coral Gables, Fla., say they will continue inserting IUDs as long as supplies last. "I intend to put them in unless different information is released," he said.

While physicians said some women have called to ask questions about having their IUD removed, more have called because they want another IUD. "We have had numerous women calling to say, 'Please save me a Cu-7 if you have one left,' " said GW's Waxman.

Some doctors are "squirreling away IUDs," said Klein, who suggested that future recipients are likely to be doctors and wives of doctors. "People are so afraid of huge malpractice suits, I don't think that people will be willing to insert them in patients."