Emerging approaches to male contraception

Abstract

Despite significant interests in contraception by men, effective methods of male contraception are limited to vasectomy and condoms. Recently, there have been several promising advances in male contraceptive research. This review will update readers on recent research in both hormonal and nonhormonal approaches to male contraception. Hormonal approaches to male contraception have been stymied by adverse effects, formulations requiring injections or implants, a 5% to10% nonresponse rate, as well as poor understanding of user acceptability. In the last several years, research has focused on novel, orally bioavailable androgens such as dimethandrolone undecanoate and 11β-methyl-19-nor-testosterone. Additionally, combinations of a topical testosterone gel combined with a gel containing segesterone acetate, a potent progestin, have shown promise in clinical trials recently. Simultaneously, significant preclinical progress has been made in several approaches to nonhormonal male contraceptives, including compounds that inhibit sperm motility such as eppin, compounds that inhibit retinoic acid binding or biosynthesis, and reversible approaches to obstruction of the vas deferens. It is imperative for these areas of research to continue making strides so that there is a gamut of contraceptive options for couples to choose from. Some of these approaches will hopefully reach clinical utility soon, greatly improving contraceptive choice for couples.

Keywords: Dimethandrolone; RISUG; male contraception; nestorone; spermatogenesis.

Figure 1.

The normal hypothalamic-pituitary-testicular axis is depicted on the left. Green arrows are stimulatory and red arrows inhibitory. On the right is the situation induced by hormonal male contraceptives in which exogenous androgens and progestins suppress the release of FSH and LH from the pituitary (dotted green arrows), depriving the testes of the local signals required for spermatogenesis.