Evaluation of d-norgestrel 1.0 mg as a post-coital contraceptive.

Two hundred and ninety-eight women were followed for 2578 months (2739 'bleeding intervals') of treatment with d-Norgestrel 1.0 mg given as a post-coital oral contraceptive. Fourteen pregnancies were recorded (general failure rate, 6.5 per 100 woman/years); at least 6 of these patients did not miss any tablet (corrected failure rate, 2.8). The acceptability rates (life table method) were 0.58 and 0.40 after 6 and 12 months of follow-up. The most important medical reason for drop-out was cycle irregularities. The cycle pattern is deeply disturbed by this method of oral contraception.