Male Contraception

Abstract

About 25% of couples worldwide use vasectomy or condoms for contraception. Vasectomy should be considered irreversible, and condoms are often used incorrectly (leading to high failure rates) and may decrease sexual pleasure. These are the only available effective male-based contraceptives, and the high usage of these methods despite the above drawbacks indicates that there is a need for novel forms of male contraception. The novel male contraceptives furthest along in development are male hormonal contraceptives. In efficacy trials, male hormonal contraceptives have failure rates of <5% – rates that are superior to male condoms and compare favorable to female hormonal contraceptives. A long-acting injectable formulation of testosterone plus a progestin is most likely to be the first commercially available male hormonal contraceptive. In clinical trials, such long-acting formulations have been demonstrated to be safe, effective, and reversible. The most common side effects are acne, gain, and modest suppression of serum high density lipoprotein concentrations. There have been some concerns about possible adverse mood effects, too. The most promising nonhormonal contraceptive is reversible inhibition of sperm under guidance (more widely known as RISUG). RISUG involves the injection of a solution of styrene maleic anhydride into the vasa deferentia where the solution solidifies into a plug. RISUG is reversible; the plug can be dissolved with a vasal injection of sodium bicarbonate. Other potential nonhormonal male contraceptives include gamendazole, molecular inhibitors of an epididymal protease inhibitor (Eppin), and inhibitors of testis-specific aldehyde dehydrogenase. The development of novel hormonal and nonhormonal male contraceptives would be useful for men and for heterosexual couples who would like additional options for family planning.