Ethynodiol diacetate and ethinyl estradiol tablets USP, 1 mg/35 mcg are indicated for the prevention of pregnancy in women who elect to use oral contraceptives as a method of contraception. Oral contraceptives are highly effective. Table 1 lists the typical accidental pregnancy rates for users of combination oral contraceptives and other methods of contraception. The efficacy of these contraceptive methods, except sterilization and progestogen implants and injections, depends upon the reliability with which they are used. Correct and consistent use of methods can result in lower failure rates. Table 1. Percentage of women experiencing an unintended pregnancy during the first year of typical use and the first year of perfect use of contraception and the percentage continuing use at the end of the first year. United States. Emergency Contraceptive Pills : Treatment initiated within 72 hours after unprotected intercourse reduces the risk of pregnancy by at least 75%. The treatment schedule is one dose within 72 hours after unprotected intercourse and a second dose 12 hours after the first dose. The Food and Drug Administration has declared the following brands of oral contraceptives to be safe and effective for emergency contraception: Ovral , Alesse , Nordette or Levlen , Lo/Ovral , Triphasil or Tri-Levlen . Lactational Amenorrhea Method : LAM is a highly effective, temporary method of contraception. However, to maintain effective protection against pregnancy, another method of contraception must be used as soon as menstruation resumes, the frequency or duration of breastfeeds is reduced, bottle feeds are introduced, or the baby reaches six months of age. Source: Trussell J, Contraceptive efficacy. In Hatcher RA, Trussell J, Stewart F, Cates W, Stewart GK, Kowal D, Guest F, Contraceptive Technology: Seventeenth Revised Edition. New York NY: Irvington Publishers, 1998, in press. 1 % of women experiencing an unintended pregnancy within the first year of use % of women continuing use at one year Among couples attempting to avoid pregnancy, the percentage who continue to use a method for one year. Method Typical use Among typical couples who initiate use of a method , the percentage who experience an accidental pregnancy during the first year if they do not stop use for any other reason. Perfect use Among couples who initiate use of a method and who use it perfectly , the percentage who experience an accidental pregnancy during the first year if they do not stop use for any other reason. Chance The percents becoming pregnant in columns and are based on data from populations where contraception is not used and from women who cease using contraception in order to become pregnant. Among such populations, about 89% become pregnant within one year. This estimate was lowered slightly to represent the percent who would become pregnant within one year among women now relying on reversible methods of contraception if they abandoned contraception altogether. 85 85 Spermicides Foams, creams, gels, vaginal suppositories, and vaginal film. 26 6 40 Periodic abstinence 25 63 Calendar 9 Ovulation method 3 Sympto-thermal Cervical mucus method supplemented by calendar in the pre-ovulatory and basal body temperature in the post-ovulatory phases. 2 Post-ovulation 1 Withdrawal 19 4 Cap With spermicidal cream or jelly. Parous women 40 26 42 Nulliparous women 20 9 56 Sponge Parous women 40 20 42 Nulliparous women 20 9 56 Diaphragm 20 6 56 Condom Without spermicides. Female 21 5 56 Male 14 3 61 Pill 5 71 Progestin only.