The introduction of reliable contraception has produced dramatic social and economic effects in the past century. With the advent of oral contraceptive pills in the 1960s, women were able to enter the workforce in much greater numbers. Meanwhile, access to reliable contraception meant more intentional family planning and lower birthrates, with adequately spaced pregnancies helping to improve the health of women and infants.
So far, ‘the pill’ has been a strictly female form of contraception, but scientists may be close to developing a similar contraceptive for males. A research team at the University of Minnesota has developed a synthetic version of an ancient poison compound, used 2.000 years ago by hunters and warriors in Eastern Africa who boiled the leaves and branches of certain plants and then coated their arrows in the tar-like mixture to serve as a cardiac poison. The effects of a synthetic version of that mixture, called ouabain, is now being studied on sperm in mice. After mice were orally administered the compound for several days, tests confirmed that it blocked sperm function to the point of producing temporary infertility, without any apparent side effects. As research proceeds, it may eventually lead to the development and marketing of a new form of birth control that reduces fertility in men.
According to projections by Global Market Insights, Inc, the global contraceptive market is expected to reach USD 33 billion in annual revenue by the year 2023. Worldwide figures from 2012, published in the medical journal for College Physicians in Canada, indicate that women take sole responsibility for planning and executing methods of contraception in over two-thirds of cases. After decades of advances in birth control options for women, current contraceptive methods for men remain limited. In past attempts to develop drugs to control fertility in men, side effects such as depression or impotence have been barriers to continued usage, especially when men are otherwise healthy and, unlike women, are not at risk of becoming pregnant. Pharmaceutical companies gradually stopped funding studies on male contraception due to declining interest in the wake of popular female methods.
In the medical world, forms of ouabain have already been used in the treatment of different heart diseases. Though ouabain has historically been derived from plants native to Eastern Africa, modern scientists discovered that it also exists naturally in the bodies of mammals as a hormone synthesised in the adrenal glands and the hypothalamus, and a 2014 clinical study in China suggested a possible correlation between natural ouabain levels and human fertility.
In the new Minnesota research, the modified ouabain compound affected the fertility of mice by reducing the movement of sperm, preventing it from being able to reach or penetrate an egg. Although the effects of ouabain on sperm function are theoretically reversible, the researchers were not able to test reversibility as part of the recent study. The results did, however, suggest that ouabain has a relatively prolonged effect on sperm motility, making it an effective choice for long-lasting contraception.
The introduction of a non-hormonal birth control pill for men has the potential to alter the sizeable contraceptive market, either by replacing current methods or by supplementing them. More convenient choices would offer new opportunities for men to share in the financial and physical responsibility—or burden—of consistent contraceptive methods. Such options could also provide men with more autonomy over their own fertility. For many, a pill would be preferable to undergoing a vasectomy, and the effects of a pill would be much more easily reversed. New options could also help facilitate more open conversations about sex, birth control, and family planning among couples.
The research team at the University of Minnesota will turn next to additional studies examining the long-term effects of ouabain in mice, before graduating to studies in humans. Such clinical trials are expensive and given the relative lack of funding from the industry, it may be difficult to obtain the needed costs in a timely manner. Further tests could also uncover potential adverse effects of ouabain to be addressed. All told, it could take several years to a decade before a male pill reaches the market.
The widespread uptake of a male contraceptive pill would not be without its challenges. Since the stakes of a potential pregnancy are lower for men than they have been for women, it is possible that male contraceptive users may demonstrate less dedication to the method. As with female birth control pills, a male option would not protect against sexually transmitted infections. In some cases, physicians may advise couples to avoid sole reliance on a male contraceptive pill and instead to pair such use with another method. While using two or more contraceptive methods can decrease the likelihood of unintended pregnancies, it also may decrease the demand for oral contraception among men if it is not seen as critical or necessary.
Nevertheless, the poison-tipped arrows of warriors in Eastern Africa may have provided us with the key to finding out.