Is it normal for a woman not to have a period on the combined oral contraceptive pill (OCP)?
Yes. Reduced menstrual flow occurs commonly among combined OCP users because all pills are progestin dominant. Remember that estrogen stimulates endometrial growth while progestins suppress it. Therefore prolonged exposure to a progestin dominant pill leads to gradual thinning of the endometrium to the point where there may be no tissue to shed at the end of the pill cycle when hormonal support of the endometrium is withdrawn. Failure to experience withdrawal bleeding (amenorrhoea) occurs in five to ten percent of combined OCP users. Many women (particularly those whose adherence is not perfect) feel more at ease when they experience a menstrual bleed signaling with few exceptions that they are not pregnant. The addition of conjugated estrogen (1.25 mg for the first ten days of one or two successive pill cycles) may stimulate endometrial growth enough to induce a withdrawal bleed.
