First, if you have not yet reached perimenopause—which may begin in your early- to mid-40s and is typified by periods that are lighter and further apart—ask your doctor to check on common conditions that often underlie irregular periods, such as thyroid problems, unsuspected pregnancy, uterine or cervical growths, endometriosis, or an infection.

If none of these is a factor, the relationship between your brain and ovaries and estrogen-progesterone production may be out of balance.

The conventional treatment is birth control pills, which will override the body's hormonal production system and regulate your cycle. However, if birth control pills don't work within three months, ask your doctor to perform a biopsy to rule out serious underlying conditions, such as cancer. The actress Fran Drescher was on the news recently because she was prescribed birth control pills for irregular bleeding; however, it was cancer rather than hormonal issues that caused her symptoms.

—William E. Schweizer, MD, New York

Chinese medicine bases treatment on the underlying imbalance causing irregularity, such as stress, nutritional deficiencies, anemia, or infections. In my experience, the most common imbalance causing irregular menstruation is "constrained liver qi." This means vital energy is blocked in the liver due to stress, unresolved anger and resentment, or faulty diet. The classic Chinese herbal formula for this is Xiao Yao Wan, or "free and easy wanderer," which contains bupleurum (Bupleurum chinense) and dong quai (Angelica sinensis).

To detoxify your liver, cut out refined or greasy foods and other liver-burdening substances, such as alcohol and drugs. Bland, simple, whole foods are best. If you have blood deficiency (anemia), eat lycium berries (available in Asian grocery stores) and meat to build blood. Several times a day, try activating acupressure point Liver 3 for five to ten minutes. Press the webbing between the big toes and second toes with gentle, firm pressure. Finally, consider relaxation techniques such as yoga or qigong to manage stress.

—Meret Bainbridge, LAc, Portland, Maine

The menstrual cycle actually starts in the brain, and there is an elegant hormonal symphony that is designed to keep it happening. Chronically irregular periods are a signal—sort of like seeing lilacs blooming in January—that something's playing out of tune.

To help maintain hormonal balance, emphasize nutrient-dense, organic foods (lean proteins, legumes, whole grains, fresh fruits, and vegetables), and be sure you are getting omega-3 fatty acids. B vitamins are especially important for hormone metabolism and can help normalize cycles. Heavy coffee and alcohol use, or smoking, can alter hormone metabolism, so you may want to back off from them. Many women notice their periods normalizing after three to six months taking chaste tree berry (Vitex agnus-castus) in the form of a tincture or extract, three times a day. Finally, anything that helps you to push your mental "reset button" on a daily basis (listening to relaxation tapes, singing, meditating, or praying, for instance) may help your cycle get back on track.

—Susan Fekety, MSN, CNM, Falmouth, Maine