Cyclic Progesterone Therapy
"Cyclic Progesterone" means treatment with the natural progesterone hormone (oral micronized progesterone, Prometrium® or compounded in oil) in a way that mimics the normal pattern (14 days in the last half of the menstrual cycle) and amount (300 mg at bedtime) in the menstrual cycle. That definition may suggest this therapy would often be prescribed. But, currently, it rarely is.
Cyclic progesterone has many potential uses. In general terms, taking cyclic progesterone is a way to prevent present or future problems (http://www.cemcor.ca/resources/preventive-powers-ovulation-and-progesterone) in premenopausal women who are otherwise healthy but for various reasons are not ovulating and making enough progesterone. These women may have hypothalamic and reversible reasons for missing, too long or irregular menstrual cycles. These menstrual cycle problems are fairly rare, most common in younger women and caused by a still "growing-up" reproductive system, plus normal life stresses and feeling alone, unloved or abused, losing weight, being ill or a combination of these. Rarely these cycle changes may be caused by some of the above stressors combined with over-activity.
More common problems for which cyclic progesterone is good therapy are called "ovulatory disturbances," including anovulation and short or insufficient luteal phases. These ovulatory disturbances can occur within "funny cycles" that are far apart or irregular, but most often are silent or "subclinical" because they occur within perfectly regular, normal-length cycles.
Cyclic progesterone is good therapy for "silent anovulation" which describes a normal menstrual cycle having enough estrogen but without regular ovulation, egg release or progesterone production. An even more frequent occurrence is a silent short luteal phase or silent insufficient luteal phase in which ovulation is present but progesterone is high for fewer than normal days or is made for long enough but in too little amounts. Currently mild high-side-of-the-breast soreness (without whole breast soreness) before flow or a monitored cycle by quantitative basal temperature are the only ways women can reliably tell if they ovulated.
Rare but important reasons for treatment with cyclic progesterone include anovulatory androgen excess (also called PCOS), for improving fertility in cycles with short or insufficient luteal phases, or to prevent the rare kind of seizures that usually occur just before menstrual flow (catamenial epilepsy). Women in very early perimenopause may take cyclic progesterone for night sweats that cluster around flow, for premenstrual breast tenderness or fluid retention and sleep problems. Women in perimenopause using cyclic progesterone to treat prolonged heavy menstrual flow or anemia often need to take in a "long cycle" (for 21 days) or daily for three months.
Currently cyclic progesterone is not officially indicated for any of these physiology-based reasons.