A 3-year follow-up study of Norethisterone Oenanthate in Nairobi, Kenya.

A prospective study of the use of the injectable contraceptive Norethisterone Oenanthate (NET-OEN) is presented using 96 subjects attending the Family Welfare Centre at the Kenyatta National Hospital, Nairobi, Kenya. 54 subjects had completed 2 years of use and 42 had completed 3 years. 2 pregnancies occured during the study period, giving an incidence of 0.07 per 100 woman months or 0.86 per 100 woman years. Both pregnancies, attributable to method failure, occured after the 5th injection, whereas earlier studies seemed to indicate higher chances of pregnancy within the 3rd month of the 1st injection. There was no marked alteration in body weight and blood pressure. 11% of the subjects with regular cycles at the beginning of the study became amenorrhic at the end of the 3 years. The dropout rate was 56% at 2 years, and 65.7% at 3 years. Thus the continuation rata at 2 and 3 years was 43.9% and 34.3% respectively. 7.2% discontinued for medical reasons, and 35% for social reasons. No patient discontinued use citing amenorrhea as a reason. Bleeding patterns have been analysed and comparisons made with Depo-Provera. This study concludes that NET-OEN is an effective contraceptive agent with relatively few side effects.