Now that health care is all sorted out, let’s turn to really important matters like sperm count.
It’s still a long way from the medicine cabinet or bedside table, but an experimental gel for men shows potential as an effective form of contraception. The gel combines the male hormone testosterone and a synthetic progestin called Nestorone. Together, the two hormones switch off production of hormones that produce sperm, researchers say.
The results of a small study on the gel were presented June 25 at the annual meeting of the Endocrine Society in Houston. The study, done at Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center (LA BioMed), involved 99 men. The study participants were randomly assigned to use one of three unidentified gels on their skin every day for six months. One gel contained testosterone plus placebo, one contained testosterone and 8 mg of progestin, and the third contained testosterone and 12 mg of progestin.
The results indicated that complete absence of sperm occurred in significantly more men who applied the combined testosterone and progestin than testosterone alone: 78 and 69 percent (8 and 12 mg of progestin, respectively). Among the men who used the gel containing testosterone only, 23 percent had complete absence of sperm.
A sperm concentration less than 1 million sperm per milliliter is considered to be compatible with very low pregnancy rates, according to Christina Wang, M.D., principal investigator of the study and professor at LA BioMed. Sperm counts reached that level in 88 to 89 percent of men who used the testosterone-progestin combinations, depending on the progestin dose. Only 23 percent of the men using the testosterone-only gel had a sperm count lower than 1 million per milliliter.
Previous male contraception studies using testosterone and progestin relied on hormone injections or implants. These forms of birth control require a visit to a doctor’s office, but the gel can be used at home, presumably increasing the likelihood that men would use it. If the product comes to market, it may be in patch form, which could also raise men’s willingness to use it. And, the study researchers say, the skin gel produces no androgenic side effects, like mood changes, acne or altered cholesterol levels.
The effects of the gel are reversible, Dr. Wang said. It takes about 12 weeks after stopping the gel for sperm counts to return to normal level, she said.
Of the 99 men who started the study, only 56 completed at least 20 weeks of treatment and adhered to the study protocol, so further studies are needed to confirm the results. In addition to the need to verify the scientific data, practical questions remain about the gel. Will men use it? Will the gel be available by prescription only, meaning insurance coverage is possible, or over the counter? How will its costs compare with condoms?
A long-term, reversible form of birth control for men could potentially reduce the number of unplanned pregnancies in the U.S. According to the Guttmacher Institute, about half (49 percent) of the 6.7 million pregnancies in the United States each year (3.2 million) are unintended. Effective and easy-to-use male contraception could also shift the dynamic of women taking on most responsibility for preventing pregnancy.