Continuous microdose (0.3 mg) quingestanol acetate as an oral contraceptive agent

Abstract

Quingestanol acetate, an oral progestin, was administered in a continuous daily dose of 0.3 mg to 382 healthy women for a total of 3,208 woman-months, for contraceptive purposes. There was a cumulative pregnancy rate of 2.9 percent and a cumulative continuation rate of only 50 percent at the end of 12 months. The predominant cause for discontinuation — 33 percent of all terminations — was menstrual cycle disruption, experienced by 86 percent of all users. The most frequent disturbance of this type was intermenstrual bleeding (63.6 percent of all users), although patients were more intolerant of amenorrhea and of menorrhagia, which occurred less frequently (19.8 percent and 2.9 percent, respectively). The incidence of systemic complaints was small, occurring in only 9.4 percent of the total acceptors for 15.7 percent of the terminations. The high incidence of menstrual cycle disturbances appears to be the major disadvantage of this oral contraceptive. The anticipated advantage of contraceptive protection without ovulation inhibition was not borne out by this study.