Take your politics to bed: after half a century of the pill, it's time to pass the birth control baton to men.
But despite the countless advances contraceptives have provided women, many devices come with the risk of serious side effects. Hormones used in the pill, patches, IUDs and vaginal rings are linked with strokes, blood clots, heart problems, breast cancer and that sadly ironic hormonal contraceptive companion, lowered sexual desire. Even spermicides can be dicey. Commonly used brands containing Nonoxynol-9, for example, can cause irritation to the vagina or rectum, increasing users' risk of STIs and HIV.
Women deserve better than the pill and its pals that still cause harm after 50 years. And women deserve a break: Simple fairness demands that their male sexual partners shoulder their share of contraception. After all, men are the leading reason women take on contraceptive risks. And women's male sexual partners have enjoyed the benefits: side effect-free and pregnancy-free sex. The pill's 50th birthday is a good time to pass the birth control baton to men.
Fortunately, new male contraceptive options are on the move, with men at study sites around the world successfully achieving temporary sterility with methods including hormonal injections and gels, sperm-blocking substances and devices, and low-tech sperm-suppressing heat methods. Labs are abuzz with panoplies of non-hormonal drugs designed to alter sperm production and cause reversible infertility. After 40 years of research on male contraceptives, what's clearer than ever is that male reproductive processes are just as easy to manipulate--and sometimes easier--than women's.
"We've got methods that could be brought to market soon--we just need the coordinated will and funding to actually make it happen," says Elaine Lissner, director of the Male Contraception Information Project in San Francisco.
Dude doubters should know that men have promised to step up to the plate. "In survey after survey in many different countries, over half the men say they'd use a male method," says Kirsten Thompson, director of the International Male Contraception Coalition, which offers general information as well as networking among researchers and advocates. These aren't just empty promises, Thompson says: Consider that men are already active participants in one third of contraceptive efforts worldwide, including vasectomies, condoms, withdrawal and periodic abstinence.
Canada stands as proof that change is possible. Just 30 years ago, the number of female sterilizations (tubal ligations) far outnumbered vasectomies, despite the fact that vasectomies are safer, quicker and cheaper. Now, twice as many Canadian men get sterilized as women. This puts their American counterparts to shame: In the U.S. there is a three-to-one ratio of tubals to vasectomies.
"Women have become more insistent that men do their part, and Canadian men agree it's fair," says Dr. Ron Weiss, Canada's top vasectomy doc. He's clocked over 27,000 so far at his Ottawa clinic.
Male contraceptive research is thriving in Canada, including Weiss's ongoing work on a reversible male method involving the vas deferens (the tubes sperm travels through). There are also encouraging results involving a removable vas deferens plug from Canadian and U.S. trials directed by Universite Laval family medicine professor Dr. Michel Lebreque and Vancouver vasectomy leader Dr. Neal Pollock. Animal trials on a male contraceptive vaccine conducted at Universite Laval showed success, but the project failed to get funding for human studies.
Challenges remain. Research money for male contraceptives comes largely from government agencies, NGOs, academia and foundations. It seems that pharmaceutical firms prefer to continue tapping the lucrative $US7 billion annual female contraceptive market. Even after a 2006 study that found up to 97 percent efficacy among 354 male subjects at six European centres testing formulations of progestin implants and bimonthly testosterone shots, pharmaceutical firms threw in the towel.
"The pharmaceutical researchers were enthusiastic, and their own studies showed male acceptance," says Thompson.
"But management decisions directed resources to more profitable drugs."
According to Nelly Oudshoorn, author of The Male Pill, a consortium of health and family-planning organizations embarked on a male contraceptive research project 30 years ago and their work has produced encouraging results. This consortium, according to Oudshoorn, gender and technology professor at the University of Twente in the Netherlands, has kept progress on male contraception moving--albeit slowly.
But despite funding cuts and other bumps, male contraceptive study subjects and research results provide hope that new male contraception methods may be as little as five years away. Here are the nuts and bolts on several approaches under development.
Vas deferens interceptors
"Male contraception is much less complicated if you target the sperm in two little tubes rather than give men something that affects their whole body," notes Lissner. She has closely followed male contraceptive research since creating the Male Contraceptive Information Project in 1994 and now champions male contraceptive projects as director of medical research programs at the Parsemus Foundation in San Francisco. Lissner's favourite male contraceptive option is called Reversible Inhibition of Sperm Under Guidance (RISUG). It involves a one-time injection of a substance that coats the vas deferens inside wall, allowing sperm to flow but rendering them unable to fertilize an egg; the injection is effective for seven years.
RISUG has proven its contraceptive effectiveness with men studied for the past 25 years in India, and animal studies prove fertility can be restored with an injection of another chemical that cleanses the contraceptive substance. Men experience no changes in libido, and the occasional side effect of minor testicular swelling disappears in a few weeks. Lissner is spearheading a not-for-profit effort to license RISUG production so it can be pursued for use in the U.S., Canada and elsewhere.
"RISUG is the most significant breakthrough in contraception, period, since the birth control pill," says Weiss, who performed the procedure in 2002 as part of a World Health Organization project in India. "It's safe, effective and easy--it took me less than 15 minutes." Weiss embarked on a RISUG approval process at the time, but Health Canada required the studies done in India to be replicated in Canada. According to Weiss, the requirement was cost-prohibitive, since he didn't have commercial backing. Meanwhile, RISUG research is flourishing in India, where ongoing phase III trials (the final step before a product is approved) at 10 centres aim to involve 1,000 male subjects.
Tests involving another vas-based device that blocks sperm flow with soft silicon plugs have also been "very encouraging," says Pollock. Study collaborator Lebreque notes that additional modifications in insertion and design would improve the trial's 80-percent sperm-blocking rate. While the U.S. National Institutes of Health funded the $US1.4 million trials and Health Canada approved the safety of the device, additional efficacy and reversibility studies are needed.
In China--which, like India, has long focused on male contraception methods in face of population pressures--studies of vas plugging methods have been ongoing for nearly three decades. Some male subjects have successfully fathered children after the plug's removal. Most recently, a vas plug with a mesh net that captures sperm showed 94 percent effectiveness in a Chinese phase II study with over 1,500 male subjects. "The key to the vas plugs is showing consistent reversibility," notes Thompson. "Just as it's harder as more time goes by to achieve fertility after vasectomy-reversal surgery, it's likely harder to show fertility after any type of longer-term vas block."
The male equivalent of the pill could be as few as five years away, experts say. Approval is most likely to come first in China or Germany, observers say. There have been studies on thousands of male subjects that indicate a male hormonal contraceptive is nearly as effective as the female pill. It produces minimal side effects and is reversible within three months of discontinued use. One catch--it probably won't be an actual pill, because oral testosterone needs to be taken several times a day to keep levels steady. Rather, the first hormonal male contraceptive on the market is expected to be a monthly or bimonthly androgen and progestin mixture that suppresses sperm production. It will be delivered by injection, implant or a daily gel application.
Like the female pill, the male pill manipulates hormones. Progestin prevents the pituitary gland from making hormones that stimulate sperm production. An androgen such as testosterone is then added to retain secondary male characteristics such as lower voice and facial hair. A bimonthly testosterone-progesterone injection is currently being used in a 400-couple study carried out in Europe, Asia, South American and Australia funded by the World Health Organization and CONRAD, the Contraceptive Research and Development Program.
Typical side effects may sound familiar to female pill-takers: slight weight gain, acne, moodiness and libido droop. Researchers also have concerns about possible effects on cholesterol levels and prostate cancer, notes John Amory of the University of Washington's Cooperative Contraceptive Research Center. The centre has been tasked by its U.S. funding agency, the National Institute of Child Health and Human Development (NICHD), with studying male contraceptives. Amory says test subjects generally find side effects quite tolerable. As for long-term effects, "We just don't know yet," says Dr. Christina Wang of another NICHD-funded male contraceptive research program at Harbor-UCLA Medical Center in Los Angeles.
Male hormonal method critics such as Lissner are concerned that users would likely experience problematic long-term side effects similar to users of female hormonal contraceptives. But whatever products emerge, men should feel assured that the bar for "acceptable" side effects is much higher than it was, and perhaps still is, for women's hormonal contraception. "The standard for male methods aims at no side effects," observes Thompson. "I'm not sure how realistic that is."
Heat and ultrasound suppression
It's long been known that heating the testes causes sperm levels to drop--that's why wannabe dads are advised to steer clear of hot tub habits and long bike rides that keep the testes too snug instead of away from the groin, where they remain cooler. Researchers such as UCLA's Wang have used heat in studies, finding that short-term daily testes baths in their trials enhanced the action of male hormonal contraceptive agents. DIY heat methods can work, says Lissner, who knows of several men who achieved temporary infertility through sustained testes soaks or specialized underwear devices that kept testes close to the inguinal canal, the enclosure where testes naturally retract in a cold environment.
Ultrasound devices, which emit very short sound waves, also deliver heat in a comfortable, quick method. Two animal studies at the University of North Carolina and the University of California are testing the effect of 15-minute testes ultrasound treatments on sperm suppression. "We're trying to duplicate some very promising research from the 1970s that found half-hour treatments kept primates infertile for three to six months," says study director David Sokal, a scientist at the non-profit Family Health International organization. Upcoming studies intend to establish human guidelines and reversibility.
"Ultrasound machines are widely available across the world," notes Lissner. "Imagine that a man could walk into a clinic and get a painless treatment while waiting for car or bike repair next door, or whatever errand, and then be set for the next several months."
Many drugs cause temporary infertility. One drug that interferes with Vitamin A receptors in the testes, for example, rendered sperm infertile in animal trials at Columbia University. Gamendazole, which induces reversible sterility in mice in a single dose, is the research star of the University of Kansas Interdisciplinary Center for Male Contraceptive Research and Drug Development. The centre received $US7.5 million from the NICHD to find non-hormonal male contraceptives. Researchers are also investigating the Chinese herb tripterygium wilfordii, a long-used treatment for arthritis and other conditions. The herb has been found to suppress sperm production. Meanwhile, contraceptive vaccines that have proven reversible in primates also provide hope for a contraceptive vaccine for men.
Make it happen
"It's hugely important to simply talk about male contraception," says Thompson. Simply talking about the risks of female contraception and encouraging male contraception and vasectomies reinforce the idea that it's fair and doable to share the responsibility for contraception. One reason more Canadian males are getting vasectomies is because "the culture changed," notes Lebreque. Similar shifts can happen with male contraception.
Next, the experts say, consumers should encourage health providers, policy-makers, family planning organizations, government officials, foundations and drug-makers to develop male contraception. One easy way to get the word out to all parties involved with male contraception is to visit www.malecontraceptives.org and fill out the short survey. Both Lissner's Male Contraception Information Project (newmalecontraception.org) and Thompson's website carry information and resources on male contraceptives.
"I got interested in male contraception because I saw women suffering with their birth control methods and I knew there were better options," says Lissner. "And I learned that there's so much potential to keep both people and our planet healthier when men can control their reproductive lives, too. I've seen a lot of change over the past years, and we're finally at the tipping point."
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|Title Annotation:||research on male contraceptives|
|Date:||Mar 22, 2010|
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