[The hormonal basis of discontinuous progestational contraception (author's transl)].

This study reports the changes in the principal biological parameters seen during the human menstrual cycle (plasma FSH and LH gonadotrophins, oestradiol and progesterone) and provoked by the discontinuous administration of a progestational agent. Fourteen women aged from 25 to 40 years, volunteers, received this treatment. In 9 women, 10 mg of lynoestrenol were administered from the 10th to the 25th day of the cycle. In 5 others, the progestational agent was given at the same dose from the 5th to the 25th day of the cycle. In all cases, there was a rapid and durable fall in gonadotrophins and ovarian steroids in the plasma. These results suggest a marked antigondadotrophic effect of the progestational agent used, which would provide effective contraception. The possibilities offered in the area of human contraception by the dicontinuous administration of progestational agents are discussed in relation with the indications of these substances, in particular during the premenopausal phase and in cases of luteal progesterone insufficiency.