Comparative evaluation of contraceptive efficacy of norethisterone oenanthate (200 mg) injectable contraceptive given every two or three monthly. Indian Council of Medical Research Task Force on Hormonal Contraception.

A total of 2388 subjects, 1181 for 60 +/- 5-day and 1207 for 90 +/- 5-day treatment regimen with norethisterone oenanthate (NET OEN) 200 mg injection, were observed for 24 months, constituting 28,513 woman-months. This clinical trial represents the largest clinical trial undertaken on NET OEN. The observations indicated that NET OEN given at 60 +/- 5-day intervals provides adequate contraceptive protection.