CeMCOR

What's Normal?

Women during the premenopausal years are making choices about education, vocation and partnerships. They may or may not choose to have children.

This stage of women’s lives lasts from the 20s until menopause. The premenopausal years make up the bulk of the entire reproductive life span from menarche to menopause that usually spans 30-45 years. Most menstrual cycles are predictable, flow lasts about four to six days and cycle lengths vary between 21 and 36 days apart. This is a time of final maturation of ovulation with over 95% of cycles being normally ovulatory with normal luteal phase lengths of 10 or more days. Women who choose to have children have them during these years. Although cramps are variable between women, usually they improve after the first childbirth.

What Can Go Wrong?

Problems related to anovulatory androgen excess and amenorrhea often persist into the premenopausal years and become established. Even women with regular cycles may have silent disturbances of ovulation. Approximately 25% of regular cycles are short in luteal phase length and about 4% are anovulatory. This may be more common in those who are very lean, who react strongly to life’s stresses, who are worried that what they eat may cause them to gain weight (cognitive dietary restraint) or who have a chronic illness.

Infertility occurs in approximately 10% of women, often because of anovulatory androgen excess or ovulation disturbances that began in adolescence.

Myths

There are two common myths during this life stage—the first is that regular cycles are inevitably ovulatory and the second is that exercise causes amenorrhea. Regular cycles may be ovulatory but they commonly have short luteal phases and about 10% of all women with regular cycles will not be ovulating at all. Regular endometrial shedding can occur just with the rising and falling estrogen levels of the normal cycle. (More info on anovulatory cycles...)

The second myth that exercise causes amenorrhea arose because many women began intense exercise at a time of stress, when they developed anorexia or were already extremely lean. The stresses, leanness, immaturity of the hypothalamic-pituitary-ovarian axis are together the cause for amenorrhea, not the running or other intense exercise itself.

Resources and Tools

• Menstrual Cycle Diary and instuctions
• A Positive View of Women’s Exercise, Menstrual Cycles and Ovulation
• Manipulating Menstruation with Hormonal Contraception — what does the Science say?
• Choices for Effective Contraception in 2006
• The ABCs of Osteoporosis Prevention (for Premenopausal Women)
• When should I have sex to get pregnant?
• Can women tell if they're cycling "egg-lessly"?