A multicentre phase III comparative study of two hormonal contraceptive preparations NET-OEN (50 mg) + E2 valerate (5 mg) given every month and NET-OEN (200 mg) given every 2 months as intramuscular injection--a report of 12-month study. Indian Council of Medical Research Task Force on Hormonal Contraception.

A phase III randomized clinical trial was undertaken to compare the efficacy, side effects and acceptability of a combined monthly injectable preparation containing NET-oenanthate (NET-OEN) (50 mg) plus oestradiol valerate (E2 Val.) (5 mg) with NET-OEN only (200 mg) given every two months. A total of 849 subjects were observed for 7817 woman-months of contraceptive use. Net discontinuation rates due to involuntary pregnancy at 12 months were 0.2 and 1.1 per 100 users for one monthly and two monthly injectable preparations, respectively. Although the monthly preparation was found to be efficacious and the subjects using the monthly preparation had a better bleeding pattern, the net discontinuation rate at 12 months due to menstrual disturbances did not show any significant difference between the two preparations. With proper counselling and motivational strategies, it is likely that acceptability of monthly injectables can be further enhanced.