Since it was first introduced in 1961, the contraceptive pill has provided an effective family planning solution for millions of couples across the world. Yet to this day, a similar hormonal solution for male contraception has been elusive. A recent clinical trial, however, seems to move us much closer to a breakthrough.
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The trial tested a pair of hormonal injections, given every eight weeks, which were designed to lower the sperm count of the participants by temporarily preventing their production of sperm cells. The injections were very effective at preventing pregnancies; among the female partners of the 266 men tested only 4 pregnancies occurred. This shows a success rate of 98.4%, which is comparable with many of the pills currently available for women.
Side effects in studies like this one are common and many participants reported adverse side effects from the jabs. The men most commonly complained of acne, libido changes, and emotional disorders, with 20 of the participants dropping out of the study because of these effects.
During the course of the trials, the researchers had to run their results past two ethics committees to ensure the side effects weren’t so significant that the study should be stopped. While the first of these review boards gave the researchers the all clear to continue, the second panel looked at the same data and ruled that the trial should be halted immediately, citing concerns about mood changes, depression and increased libido.
While it’s difficult to know exactly why the decision was taken to stop the trial, it is reassuring to know that this does not signal the end of research into male contraception. When asked, over 75% of the study’s participants said they were satisfied with the injections as a method of contraception and would be happy to use them if they were commercially available. The study’s authors, too, are optimistic about the future of the method, telling the BBC they are working on combining different levels of the hormones, as well as different ways of delivering them, such as gels.
It’s still difficult to believe that the development of a male contraceptive pill has taken so long. Such pill would alleviate the burden of birth control from women and bring more equality to the realm of family planning. While social factors no doubt play into this continuing inequality, there are simpler biological factors at play too.
The basic mechanism of all contraception is preventing sperm from meeting egg in the uterus. It’s convenient, therefore, that there exists a state in which egg release stops completely: pregnancy. Female contraceptives work by mimicking the hormonal environment of pregnancy, preventing any egg release from the ovaries. Sadly, there are no such natural breaks in sperm production – from its beginnings during puberty, production of the cells continues until death, at the startling rate of 1,000 sperm per second.
It is therefore a significant medical achievement to have reversibly prevented sperm production in the way that this study shows. The challenge now will be to limit the side effects of the treatment and, perhaps more importantly, to find a more cost effective and practical method of delivering it to patients.