Monthly Injectable Contraception with Norethisterone Enanthate plus Estradiol Valerate

Abstract

Long-acting parenteral contraception was in its heyday from the late sixties through the mid-seventies [1]. At this time the method was based on estrogen-free depot-progestagens. The effect of a single dose lasted several months, providing high contraceptive efficacy, and was well accepted, especially amongst women of some developing countries [2, 3]. However, the main drawback consisted of poor cycle control, i.e., amenorrhea and/or intracyclic bleeding; this inconvenience accounted for the limitation of or even a decrease in the use of these preparations. The addition of an adequate estrogenic component and the monthly administration scheme were the obvious solutions. Thus, despite the fact that the first publication dates back to 1963 [4], the monthly injectables were somewhat neglected and became the focus of interest again only about 10 years ago. This may explain why, despite a large number of publications, the optimal drugs and doses for monthly injectables have still not been conclusively established [5, 6].