In a year-long study of reversible male birth control, 320 men aged 18 to 45 received regular hormone shots to the buttocks. The shots had the intended effect of shrinking the men’s sperm counts and preventing pregnancies, researchers announced this week in the Journal of Clinical Endocrinology and Metabolism.
"The study regimen led to near-complete and reversible suppression of spermatogenesis," the results in the journal stated. "The contraceptive efficacy was relatively good compared with other reversible methods available for men."
However, the test subjects reported mild to moderate mood disorders (sound familiar, ladies?) as well as acne.
The study was conducted in two phases, Ars Technica explains. In the first phase, men were given injections of progestogen and testosterone every eight weeks for 24 weeks. By the end of the first phase, 96 percent of those participating in the study had seen their sperm counts plummet to fewer than 1 million per milliliter, in contrast to normal levels of 15 to 200 million per milliliter.
In the next phase, the men, all in monogamous, heterosexual relationships, were asked to stop using other forms of birth control. By the end of this 56-week phase, four women got pregnant and six men’s sperm counts rebounded. Overall, the success rate of the shots was 92.5% – as effective as hormonal birth control for women and more effective than the actual use effectiveness rating of the male or female condom alone.
However, the men suffered – so much so that the study was ended early. Nearly half of the 320 men who started the study (46%) developed acne, 38% reported an increased sex drive, 23% had pain at the injection site and 17% reported emotional disorders, Ars Technica reported. Twenty men dropped out of the study because of the side effects.
"The safety committee felt that the number of side effects, particularly the mood changes, were too many," researcher Mario Festin, a medical officer in the World Health Organization’s Department of Reproductive Health and Research, told the Chicago Tribune. "[A]t that point, the study had already proven that the drug combination could already produce the desired effect of lower sperm counts, and the unfavorable side effects may outweigh any further findings."
Women beginning a hormonal birth control regimen are regularly cautioned to expect nausea, weight gain, headaches, bleeding, a lowered sex drive and mood swings. A study in September that covered information for 1 million women over 14 years found that a common oral contraceptive pill that combines two key hormones increased women’s rates of taking antidepressants by 23 percent, and nearly doubled the rate among teens taking this type of pill.
A recent Broadly report details the coercive practices used in testing hormonal birth control on women not so many decades ago, in which subjects had no option to drop out of the studies they often didn’t even know they'd been put into. Birth control for men was tested back then, too. That idea was abandoned because of the side effects. "It was believed women would tolerate side effects better than men, who demanded a better quality of life," Broadly noted.