Development of Male Birth Control... Where has it been?


With overwhelming amounts of female birth control available, where has male birth control been and how developed is the science?

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By Ben Morris

Since the discovery that both sperm and egg had to be in union to produce an offspring in the 1850s, the burden has almost always fallen on the egg-carrier to work to prevent this union. Scientists have worked for nearly two centuries to churn out options for female birth control – both hormonal and non-hormonal. However, many of these can cause life altering side effects and are not an option for all women. Contrastingly, the only two options for men – condoms and vasectomies – are non-hormonal and minimally invasive.

The responsibility of birth control in most heterosexual relationships almost always falls on the woman. It may be argued that this is due to the lack of options for male contraception. So where are the options?

The earliest evidence of orally administered contraception was in the ancient Greek and Roman colony Cyrene, in Libya, where people often ingested the crushed leaves of the silphium plant – a relative of fennel. It was used as a coughing suppressant, aphrodisiac, food and, most relevantly, as a contraceptive, mostly taken by women to ‘purge the uterus’. News spread fast of this miracle plant. Quickly, it became as valuable as precious metal. The reliance on silphium quickly led to its extinction. It has not yet been conclusively rediscovered, but its identity remains debated, as are its contraceptive properties.

The main obstacle to overcome when creating male contraception is the rapid production, and sheer number, of sperm. They must all be disabled and stopped from reaching the egg, hence why barrier methods are the easiest way to combat this problem. In 2016, a study published by The Journal of Clinical Endocrinology and Metabolism reported a new, injectable male contraceptive that suppressed sperm production in 274 of the healthy male participants – reducing sperm count to around one million sperm cells per millilitre of semen; normal levels are anywhere above 15 million per millilitre. The injection regimen involved intramuscular administration of 200mg of norethisterone enanthate, the active agent, alongside 1000 mg of testosterone undecanoate, to counteract the reduced levels in male hormone from the treatments. These were administered every eight weeks.

During the study, only four pregnancies occurred during the ‘efficacy phase’ – the part of the trial that tests for how well the drug works – which monitored 266 men and their female partners. Many participants dropped out of the study during this phase, resulting in only 111 completing the final phase before recovery. Following the 52-week ‘recovery phase’, 94.8 percent of the participants’ sperm counts returned to normal levels. This makes the drug sound promising, as it does not cause longterm fertility issues for the majority of subjects. However, in 2011, WHO intervened and stopped new recruitment for the trial, claiming that the rate of side effects reported was too high, with 1491 incidents reported, including acne, injection site pain, increased libido and mood disorders – similar side effects to its female counterpart. Yet, 38.8 percent of incidents reported were found to be unrelated to the trial. Injections may not be viable for wide use, as administration requires training or professional help, so pills may be a better option.

A study published in 2018 demonstrated promising results of orally administered dimethandrolone undecanoate (DMAU for short). Subjects were healthy men, aged 18 to 50, with “general good health and normal reproductive function”. This trial was double-blind, meaning some participants unknowingly received a placebo, others the active drug at different doses, and not even the researchers were aware of who had what. DMAU works by suppressing two hormones on which sperm production is dependent: follicle stimulating hormone (FSH), which stimulates the production of sperm, and luteinising hormone (LH), which causes cells in the testes to produce testosterone.

The aforementioned study shows that DMAU does just that. Over a 28 day regimen of this pill, the results showed that, as the dosage of DMAU increased, levels of testosterone, LH and FSH decreased. Researchers did not measure sperm count. Longer studies will be needed to monitor its effectiveness in reducing sperm count, which the study did not do, meaning there are no conclusive results that DMAU reduces risk of pregnancy – since the body takes 90 days to produce sperm, side effects may become more severe. Side effects reported over the 28 days were similar to the injected drug: acne, change in sex drive – similar to the female pill – alongside mild erectile dysfunction and weight gain.

Indeed, there are many promising options, but studies demonstrate perhaps an inconsistency in how side effects for birth control are regarded. Studies into male birth control present side effects as unacceptable, worthy of promising trials being shut down, yet female birth control, that is already available, has many of these side effects and more. If these risks were viewed the same, regardless of sex, male birth control may have already been available. Such attitudes still hold back male birth control to- day. There is still a long way to go, but the science is nearly there. Many studies are still in the works, now it is just a matter of time, money and resources.