Approaches to Contraceptive Methods for Men

Abstract

Unlike female contraception methods, male contraception has had no new approved approaches since the introduction of no-scalpel vasectomy over 40 years ago. Men who wish to share family planning responsibilities have withdrawal or condoms as available reversible methods of contraception. These methods have a high failure rate and are user dependent. While a vasectomy can be surgically reversed, it should be considered a form of permanent contraception because pregnancy in the partner cannot be guaranteed after reversal. Experimental methods, including chemicals to block the vas deferens, are undergoing testing. Since the 1970s, hormonal male contraception using testosterone alone and testosterone combined with a progestin demonstrated high efficacy and few short-term adverse effects. Long-term adverse effects cannot be determined until a hormonal male contraceptive method is approved, allowing safety studies to be performed. Contraceptive efficacy studies have shown failure rates comparable to those of hormonal female contraception. Current studies focus on user-controlled methods such as daily transdermal gels, oral pills, and long-acting injectables. Large-scale population studies performed in the early 2000s confirmed that over 50% of men surveyed would try a new male contraceptive, preferring an oral pill over injections or implants. These surveys also showed that over 80% of the women welcomed a new method of contraception, and over 90% of them would trust their partner to use the male method consistently. With changes in gender roles and gender equity in relationships, it is anticipated that male participation in family planning methods will be enhanced. Successful efficacy, safety, and reversibility with hormonal male-directed methods may pave the way new, targeted nonhormonal approaches. Once the testicular target is selected, new compounds can be identified based on structure function analyses or high-throughput screening to identify agonists or antagonists of the target.