Safe, convenient, reversible contraception allows women and men worldwide to plan their families and ensure that they are ready to nurture and provide for the children they parent. So why are so few male contraceptive methods available?
In America, 62 million women are of childbearing age; worldwide, the number is around 1.5 billion. In the US, when these women get pregnant, half of their pregnancies will be unplanned and 42% of these end in abortion. Approximately 40% percent of pregnancies worldwide are unintended. Globally, about half of all abortions are considered unsafe and more than 75% occur in developing countries. In order to reduce the number of unsafe abortions worldwide, and to equip individuals with tools they need to take control of their reproductive lives, we need to ensure the availability of reversible, effective birth control solutions with minor side effects for both men and women.
While only two male contraceptive options (vasectomy and condoms) are available, they are both widely used, making it clear that men are willing to accept responsibility for birth control. In fact, one study assessed the responsiveness of men from four continents and nine countries to the possibility of "male fertility control," and found that on average more than half of those surveyed were willing to use such a method. The legal responsibility associated with fathering a child is also motivating men to take control of their reproductive fate.
Around two-thirds of women in their reproductive years are sexually active with no intent of getting pregnant, and a typical woman in America uses contraceptives for around three decades of her life to avoid pregnancy. And yet the most popular forms of contraceptives - female hormonal birth control and the condom barrier method - are not failsafe. One study found that "traditional" usage of these two methods resulted in an 8% and 15% failure rate, respectively. In another study where pill usage was monitored by both an electronic device and the woman herself, inconsistencies between the two records highlighted the unreliability of daily birth control usage. The women reported proper pill usage 53-59% of the time, while the device reported an accurate value of 19-33%. A birth control method that relies on the user to either administer daily dosages or use at the time of need is not foolproof.
Additionally, current female hormonal contraceptive methods act systemically, and carry with them many side effects, including nausea, headaches, weight gain, depression, loss of libido, as well as menstrual problems. "New" birth control methods often simply mean a lowered or altered dosage of estrogen and progestins, respectively, or a method, like the NuvaRing, that does not require oral and daily administration. Given that the female birth control pill was introduced nearly 50 years ago, it is an embarrassment to the scientific community that there remain so few alternatives to hormone-based therapies.
In a society which strives for equal opportunities for both men and women, responsibility for birth control should not fall solely on women, nor should we be content with birth control options currently available to women. The idea of a male contraceptive method has been discussed for decades, and articles appearing in mainstream media frequently promise a male birth control pill in pharmacies in the near future. Unfortunately, a lack of funding and interest from pharmaceutical companies has delayed progress in this field. Most private industries are no longer interested in funding male contraceptive research, for multiple reasons, including a complicated FDA approval process due to lack of previous experience with male birth control, reduced insurance coverage of contraceptives in general, and a high development cost for a product that would be ideally of low purchase cost, especially in developing countries. This leaves the public sector as the sole source of funding, which comes with it both budget and experimental constraints. But despite this shortage of financial support, many innovative scientists around the world are working to make male contraception a reality.
In order to develop a male contraceptive, we must first understand what is needed for proper male fertility, so that we can suppress or block that function. While 50% of infertility in couples is male factor, a recent study of infertile men attributed infertility to low sperm motility and low sperm count. Identification of a molecule that is required for male fertility can facilitate contraceptive development, but may also help in treating individuals struggling with infertility.
Successful fertilization is a complicated, evolutionarily fine-tuned event, which, on a basic level, requires the fusion of a sperm and egg. Female hormonal contraceptive methods block egg production. There are three biological mechanisms to impede male fertility:
- Arresting sperm production
- Blocking sperm from entering the female reproductive tract
- Interfering in sperm-egg binding
In this article series I will explain the scientific technologies behind the current global male contraceptive research efforts, describing what is in the pipeline in terms of both hormonal and non-hormonal contraceptive approaches. I will divide these technologies in three categories based upon the mechanisms described above. New approaches should offer clear advantages over existing methods, for example, hormonal methods that deliver progesterone and testosterone to block sperm production in men. Non-hormonal methods offer the benefit of a targeted and therefore effective approach, including those methods that block sperm from passing through the vas deferens, as well as heat and ultrasound approaches that arrest sperm production.
Ideally, a male contraceptive would be effective, reversible, with few side effects. When it is, not only will we have secured a victory for equality of the sexes, we will offer couples worldwide a new method for ensuring that they are able to choose parenthood when they are ready.
Stay tuned for more articles from Soumya Vemuganti about latest research on contraceptive methods for men.
