• Less iron deficiency anemia, due to lighter menstrual bleeding,
• More regular menstrual cycles,
• Less dysmenorrhea, and
• Less severe premenstrual symptoms.

Because of higher blood iron levels, OC users are less likely than nonusers to develop iron deficiency anemia (147, 328, 466). Also, by preventing unwanted pregnancies, OCs—like other contraceptives—prevent anemia associated with pregnancy (484). In developing countries anemia is a serious health problem among women, many of whom suffer from inadequate diets, parasitic infections, and the strain of repeated pregnancies. As many as half of women of reproductive age in developing countries may have subnormal levels of hemoglobin, the iron-containing pigment of red blood cells (532, 536).

Some 60% to 80% of women who use OCs bleed less heavily during menstruation than before starting OCs, and on average OC users lose 50% to 60% as much blood per cycle as other women (147, 260, 302, 328, 382, 433, 438). A 1992 Swedish study found that a low-dose OC, containing 30 mg ethinyl estradiol and 0.15 mg desogestrel, reduced menstrual blood loss to 56% of previous levels (260).

More regular menstrual cycles. Oral contraceptives generally improve menstrual patterns (179). For example, a UK study of 2,115 women ages 18 to 49 found that most OC users had shorter, lighter periods that occurred at more regular intervals (49). Only 7% of OC users reported irregular periods, compared with 10% of IUD users, 11% of women relying on female sterilization, and 12% of women using other methods or none. The Oxford University/Family Planning Association (Oxford/FPA) cohort study found that, compared with nonusers, OC users or recent OC users (within the previous 12 months) were two-thirds as likely to be referred to a hospital for treatment for irregular periods (495).

IEC, Center, State Information Service, Egypt Ministry of Information

This Egyptian poster reminds pill users, "Don't forget to take a pill every day. If you forget, take it with the pill of the following day."

OCs are a standard treatment for dysmenorrhea (50, 189). A 1990 Swedish study found that users of both monophasic and triphasic low-dose OCs had less severe dysmenorrhea than nonusers (309). Combined OCs appear to be more effective than progestin-only pills at reducing dysmenorrhea (68).

Less severe premenstrual symptoms. Several studies have found that premenstrual symptoms are less severe among OC users than among other women (20, 100, 166, 253, 311, 341, 427). Differences in defining and measuring symptoms, however, make it difficult to compare the effects of different formulations (11, 294, 308, 309). Premenstrual syndrome, a condition caused by natural hormonal changes, begins at the middle of the menstrual cycle and tends to intensify in the last seven days before menstruation. Multiple physical and/or emotional symptoms characterize premenstrual syndrome, such as headache, fatigue, acne, backache, breast soreness, changes in sexual desire, nervousness, difficulty concentrating, irritability, anxiety, and depression. Symptoms subside when a woman begins to menstruate. Most women experience noticeable premenstrual symptoms at some time; 10% or less report severe discomfort (50, 225).