Cyclic Therapy

Each regimen has advantages and disadvantages (Table 10). Cyclic therapy is the most widely used regimen in the United States. It closely mimics the normal premenopausal ovulatory cycle both in timing of hormone secretion and resulting bleeding patterns. As in a normal menstrual cycle, the addition of progesterone initiates a secretory phase. The subsequent withdrawal of progestin causes sloughing of the endometrium, and thus menses. Bleeding usually begins 1 to 2 days after the last progestin dose and continues for 2 to 3 days during the pill-free interval. Regardless of whether bleeding has stopped, a woman should take her next estrogen tablet on the first day of the following cycle.

Table 10

Major drawbacks of the cyclic regimen include the possible recurrence of vasomotor symptoms during the estrogen-free interval and the return of regular monthly bleeding. Both of these drawbacks can affect patient compliance. Many women object to the return of monthly periods and discontinue HRT. With this regimen, however, bleeding is predictable and can be planned for specific times.