Starting Monday, an easily understood brochure on the benefits and risks of intrauterine contraceptive devices must be provided to each prospective IUD user. Extra copies will be available in clinics and physicians' offices.

The Food and Drug Administration in an order last May to manufacturers to supply the brochures, said it wanted to help women make informed decisions on whether an IUD is the appropriate birth-control method in each individual case.

The FDA first served notice 28 months ago of its intention to require a patient brochure. The leaflet is a companion to a patient brochure for birth-control pills that was based on 1968 data was issued in 1970 and is still in use.

For more than two years however, the agency has been in the process of updating the pill leaflet to reflect new information that has become available over the last nine years about its hazards, especially to women in their 30s and early 40s.

Commissioner Donal Kennedy, in a statement yesterday about the IUD brochure, said, "I am firmly committed to the general concept that consumers must participate more actively with their physicians in choosing drugs and medical devices . . . "

Currently, an estimated 3 million women in the United States are fitted with IUDs. Kennedy emphasized that the FDA's goal is to assure that from now on, each woman and her doctor have the information needed to choose the most suitable form of contraception, not to advocate one or another method.

Under the FDA's order, doctors must give women an opportunity to read the IUD brochure and to ask questions before the patients decide to have the device inserted.

Before an IUD is inserted, the brochure advises, a woman should tell her doctor if she ever had, or suspected she may have had, any of the following conditions that could make the device unsuitable:

"Abnormalities of the uterus (womb): allergy to copper; anemia; bleeding between periods; cancer of the uterus (womb) or cervix; fainting attacks; heart disease; heart murmur; heavy menstrual flow."

Also, "Infection of the uterus (womb) or cervix; pelvic infection (pus in the fallopian tubes); prior IUD use; prior uterine surgery; recent abortion or miscarriage: recent pregnancy; severe menstrual cramps; suspected or possible pregnancy."

Also, "Suspicious or abnormal 'Pap' smear: unexplained genital bleeding: vaginal discharge or infection: veneral disease: Wilson's disease."

Generally, the brochure is the same for all the IUD types and brands, except that it differs from type to type on pregnancy and adverse-reaction rates. The FDA estimates pregnancy rates per 100 women per year range from one to six, compared with less than one to two for the most widely sold pills - those containing 20 to 23 micrograms of estrogen.

To improve the IUD's reliability, tye brochure recommends supplemental use of a less efective contraceptive, such as vaginal foam, cream or jelly, or condoms.

Other differences are size and shape, composition (metal or plastic), and color and number of the "tail" or thread, which enable a wearer to check whether her IUD has come out of the womb withour her knowing it.

In the "warnings" section, the brochure advises a user to call her doctor "for any of the following reasons:

a) severe or prolonged bleeding . . . you may need to have the IUD removed to prevent the development of anemia.

b) Pelvic pain and cramps. This could mean an infection has developed requiring treatment.

c) Exposure to veneral disease (VD). If exposure . . . is suspected, report for examination and treatment promptly. Failure to do so could result in serious pelvic infection . . .

d) Tail or threat disappearance . . . it is possible that the IUD has been expelled or displaced or that perforation has occured."

In a "special warning about pregnancy with an IUD in place," the brochure urges a wearer to see her doctor "right away" if she misses a menstrual period, has a scanty flow during the period, or suspects pregnancy.

"Serious complications of sepsis (severe infection), spetic abortion (infected miscarriage), and death have occurred when a pregnancy continues with an IUD in place," the brochure warns. "Most of the occurences of these serious complications have been reported in the middle third of pregnancy . . . Removal of an IUD in pregnancy decreases the likelihood of serious complications."

The brochure says that how the IUD works to prevent conception "is not completely understood." Its unique advantage is that, once inserted, it requires no preparation or further steps before intercourse. Some IUDs may be worn until the woman wishes to conceive; others must be replaced annually if the user is to be protected from pregnancy.

In separate sections on "adverse reactions" and "side effects," the brochure takes up topics including bleeding following insertion, relief of temporary pain, expulsion and painful intercourse.