This news release describes an efficacy and safety study of an injectable hormonal contraceptive for men that involved 320 men in seven countries. The news release quantified benefits and described adverse effects in some detail while emphasizing the need for more research. However, it did not discuss an important study limitation — the absence of controls — or costs. A comparison with the efficacy and safety of other forms of birth control would have made the release much stronger.
The development of new forms of birth control including male hormonal contraceptives has been stalled for years, partly due to lack of interest on the part of drug companies. That’s despite the fact that many men have indicated a willingness to use hormonal contraceptives, while some women are reluctant to use available birth control methods due to their own experiences with side effects. Better male birth control options could erode cultural and economic barriers to contraception and reduce unintended pregnancies, fostering better economic and health conditions worldwide. This study, funded by the United Nations and other governmental and foundation sources, is the first large multi-center study to test a combination of testosterone and progestogen in men. According to the researchers, it establishes a much-needed reference point for future trials of male contraception. We would have liked to see some discussion of the economic, cultural and logistical barriers that could impede the introduction of a new form of birth control in the release.
The cost of these hormone injections isn’t mentioned, and there’s no assessment of how the cost might compare with other forms of birth control. It should be noted that people interested in using this injection for birth control would also need to factor in clinic visit costs and potential treatment of side effects.
The news release states that hormone shots were effective at reducing sperm count to less than 1 million/mil within 24 weeks in 274 participants and was effective in nearly 96 percent of continuing users, with four pregnancies occurring among the men’s partners during the efficacy phase of the study. It also stated that more than 75 percent of participants reporting being willing to use this method of contraception at the conclusion of the trial.
That’s the plus side. One omission from the release was the absence of a control group. Without a control group it’s not possible to accurately calculate the effectiveness. The study reported four pregnancies among the men taking the injection. How many pregnancies would be expected for a similar group not getting the shots? The news release doesn’t say.
The news release discusses adverse effects. It says researchers stopped enrolling new participants in 2011 due to the rate of reported side events, particularly depression and other mood disorders. It also mentions that men reported having injection site pain, muscle pain, increased libido and acne, and that 20 men dropped out due to adverse effects. It also says serious adverse events that were assessed as probably or possibly related to the study included one case of depression, one intentional overdose of acetaminophen, and a man who experienced an abnormally fast and irregular heartbeat after he stopped receiving the injections.
Further, it quotes a researcher saying that “the combination of hormones needs to be studied more to consider a good balance between efficacy and safety.”
Despite the attention to side effects there were a few gaps. The release didn’t quantify the number of men who developed depression. It noted there was one suicide among the study group, but stated it was determined not related to the hormones. How was it determined that the injection did not contribute to the suicide when the hormone shots did contribute to mood disorders? The release doesn’t say.
The news release also doesn’t adequately explain the need to cancel the study due to harms. When compared to the side effects of other hormonal contraceptives used by women it appears to be safer.
The news release describes study methods in detail. However, it could have pointed out then lack of a control group and the limitations of hormone injections. For example, this study included only men who reported being in monogamous relationships for at least a year. Presumably, these men were open to the idea of taking hormone injections while other men in the general population might not be. Injections require advance planning and access to medical resources, unlike other reversible methods of condom use and withdrawal. In this study, couples were required to use another form of birth control for as long as 26 weeks while the hormone injections took effect.
The news release also does not mention that it took eight of the men more than a year to recover their sperm counts, which could be a drawback for some couples.
The news release does not appear to be disease-mongering. It states that better birth control options are needed for men, citing data from the Guttmacher Institute that 40 percent of pregnancies worldwide in 2012 were unintended. Of course, expanding contraceptive use would not eliminate all unintended pregnancies.
The news release states that the research was co-sponsored and funded by UNDP/UNFPA/UNICEF/WHO/World Bank Special Program of Research, Development, and Research Training in Human Reproduction in Geneva, Switzerland, and CONRAD, using funding from the Bill & Melinda Gates Foundation and the U.S. Agency for International Development. It also states that the hormones were provided by drugmaker Schering, which has since merged with Bayer.
The news release mentions other available birth control methods for men including condoms, vasectomies and withdrawal. However, it should have given readers an idea of how the efficacy rate of injectable hormones compares with other available methods of birth control. According to the study, the efficacy of male injectible hormones is high when compared with other reversible methods available for men, and is comparable with the efficacy of female oral contraceptives.
Also, the news release did not mention other approaches to male birth control under study, which include hormone-containing gels applied to the skin and the synthetic hormones that could be formulated into a pill as well as non-hormonal mechanisms to prevent sperm development, according to the Eunice Kennedy Shriver National Institute of Child Health and Human Development.
The study does not give the impression that injectable hormones for men are readily available. In fact, it quotes a researcher stating that “more research is needed to advance this concept to the point that it can be made widely available to men as a method of contraception.” However, it could have mentioned that in addition to safety issues, there are other barriers to making male injections widely available. For example, a drug company would have to be willing to make it and sell it at an affordable price.
The news release does not overstate the novelty of this research, quoting a researcher who says the findings “confirmed the efficacy of this contraceptive method previously seen in small studies.”
The news release does not engage in sensational language.