31.   Experts say because childbearing and subsequent breast-feeding reduce the lifetime number of menstrual cycles, they may reduce the exposure of breast tissue to cancer-promoting estrogens.

32.   For example, women have different drug sensitivities depending on which phase of their menstrual cycle they are in.

33.   For women whose menstrual cycles are irregular, the pill provides predictability.

34.   Haney said an alternative treatment, birth control pills, is effective for giving perimenopausal women control over their menstrual cycles.

35.   Headaches, hair loss, water retention, breast tenderness, hot flashes, irregular menstrual cycles and extreme menstrual cramps are not unusual.

36.   Hormonal changes can cause bad breath for women before their menstrual cycles.

37.   If eggs are later inserted in a normal menstrual cycle rather than one boosted with IVF drugs, the levels of relaxin in any resulting pregnancy should be normal.

38.   In modern times, synchronous oscillations have even been observed in the menstrual cycles of women confined together in prisons and college dormitories.

39.   In women, the menstrual cycle rhythm of changes can strongly influence the effects of brain and body chemicals as well as any medications they may be taking.

40.   It works in conjunction with a second drug that triggers uterine contractions, and must be given within three weeks after the first missed menstrual cycle.