Norethisterone enanthate as an injectable contraceptive in puerperal and non-puerperal women.

Norethisterone enanthate (NET-EN) was intramuscularly administered to 5 puerperal women and 20 non-puerperal women for a total of 366 months. Contraceptive effectiveness and side effects of the drug were evaluated. Basal levels of LH, FSH, prolactin (PRL), estradiol 17 beta (E2) and progesterone (P) were measured in blood samples collected from 5 non-puerperal women, while LH, FSH, PRL and norethisterone (NET) plasma levels were evaluated in puerperal women. NET was also assayed in plasma from breast-fed newborns. No woman became pregnant. Side effects consisted of only menstrual abnormalities. Ovulation (P plasma levels higher than 2000 pg/ml) was achieved in 3 patients during the first month of NET-EN treatment but luteal function appeared to be insufficient. In puerperal women, NET plasma levels showed a course similar to the one observed outside puerperium. Lactation was not inhibited, and NET transfer to newborn through milk was negligible, since NET was undetectable in newborn plasma when maximal levels were measured in the mother. It was concluded that NET-EN is an effective contraceptive drug, deprived of major side effects, and particularly useful in women affected by metabolic diseases or during puerperium.