BERKELEY, CA (UroToday.com) - The population of our planet continues to grow at an alarming rate. If the growth continues at the present rate, the estimated population of seven billion is expected to double in 40 years. Since the introduction of the oral contraceptive pill for women in the 1960s, there have been numerous collaborative efforts by scientists and pharmaceutical companies to improve the effectiveness, proper dose, and delivery of contraceptives to women who wish to safely regulate their reproductive physiology. The so called," contraceptive revolution" of the past century has helped millions of women in developed nations to practice family planning by safely spacing births. However, for the majority of women in developing nations, the contraceptive revolution of the 60s has yet to come because many of the available contraceptives are too expensive for regular use. The availability of safe, reliable, reversible, and affordable contraceptives for men and women is crucial to the health and quality of family life in both developed and developing nations.
Male contraceptives are methods of preventing pregnancy that primarily involve male physiology. Contraceptives for men can be achieved by suppressing/preventing sperm production in the testes or preventing sperm from reaching the site of fertilization, or interfering with the sperm function necessary for normal fertilization. The contraceptives currently available for men are based on approaches that prevent sperm from reaching the egg using either device-free traditional approaches (i.e., abstinence or withdrawal) or barrier approaches (i.e., use of condoms or vasectomy). When not defective and used properly, condoms can protect women from unintended pregnancies as well as from low-/high-risk papillomaviruses. However, condoms and traditional approaches have relatively higher typical-use failure rates, whereas vasectomy is largely irreversible and not suitable for younger men. Despite the sharp rise in world population, no new methods have been introduced in the past century to regulate male fertility.
The article gives sufficient background information on male anatomy and physiology as well as male contraceptives and why men need them. In addition, information is provided in family planning and its benefits in raising a happy and healthy child in a resourceful family. In spite of a general agreement that sexually active teenage boys and young men must take full responsibility of their fertility, safe and affordable contraceptives for males have lagged behind because of the complexity of the science of the male reproductive system. Finally, the article discusses currently available contraceptive choices for men and new hormonal and non-hormonal approaches that are at various stages of research and development that will lead to new contraceptives for men. These approaches are summarized in a table which is easy to follow.
Three vas-based male contraceptive approaches that are inching closer to being approved for use by men in multiple countries are:
- The reversible inhibition of sperm under guidance (RISUG) approach being tried in India, uses non-toxic chemical maleic anhydride dissolved in dimethyl sulfoxide (DMSO). Within minutes after the solution is injected into the lumen of vas deferens tubes, the chemical polymerizes and anchors to the inner wall of the vas partially or fully closing it and preventing spermatozoa from going through it. Moreover, the poly-electrolytic nature of the chemical kills sperm cells when they come in contact with the chemical. This method can be reversed by the injection of DMSO or sodium bicarbonate which solubilizes the chemical and flushes it out of the vas tube. The approach is undergoing advanced clinical trials in India which means approval for use in Indian men in early 2015.
- The RISUG approach is gathering interest beyond India. In 2010, Parsemus, an organization in the USA bought the international rights to the RISUG technology. It has been renamed as Vasalgel, a multi-year male contraceptive. Similar to the RISUG approach, a gel of maleic anhydride is injected into vas tube. The polymer allows fluid to pass through the vas tubes but retains spermatozoa. If a man wishes to restore the fertility, the gel is flushed out as in RISUG. The approach has completed toxicology testing in the USA and will likely be approved by the FDA for use as a safe and reversible contraceptive for men in early 2016.
- Finally, Chinese researchers have introduced an intra-vas device (IVD) that blocks the flow of sperm through the vas tubes. The new generation of IVD uses a set of tiny preformed polyurethane implants filled with a medical grade nylon mesh (sieve) to capture spermatozoa in the vas. The flow of sperm can be restored by removing the implants. The approach has undergone multi-center clinical trials in China with good efficacy and proven reversibility. The procedure will likely be approved for use by Chinese men in early 2015.
In summary, we have discussed various hormonal and non-hormonal approaches to regulate fertility in men, and that are in various stages of research and development. It is concluded that intra-vas approaches will prove safe, reversible, and affordable contraceptives for men within one year. The availability of these male contraceptives will allow men and women to take full control of their fertility in family planning.
Daulat R. P. Tulsiani, PhD and Aida Abou-Haila, DSc as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.
Department of Obstetrics and Gynecology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA