Norethisterone oenanthate as an injectable contraceptive: a study of patients discontinuing treatment

Two hundred and ninety-five women were enrolled in a study of norethisterone oenanthate (NET-OEN) as an injectable contraceptive. One hundred and twenty-four patients who discontinued this contraceptive have been studied in detail. The main reasons for use-related closures of method were menstrual abnormality (22 patients), minor side-effects (23 patients), personal reasons (22 patients) with 18-month life-table net discontinuation rates of 14.7/100 women, 13.5/100 women, 14.2/100 women. There were no accidental pregnancies. The probability of discontinuing treatment was not affected by age, parity, time of starting treatment or previous contraception. Sixty-nine per cent of all discontinuations occurred in the first four months of treatment. There were no serious complications.