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Friday, January 23, 2009

The male pill

In 2001 a breakthrough study by scientists at Edinburgh University led to the hope that an alternative form of male contraception would be available within five years. Six years later, we look at the latest developments in the search for a male contraceptive pill.
Lab results have yet to produce a male contraceptive pill.
What methods of contraception do men use?For men, the options are:
condoms, which are unpopular with a lot of couples
coitus interruptus (withdrawal), which is an unreliable form of contraception
vasectomies (sterilisation) that cannot be reliably reversed.All other methods of birth control are for women.What kinds of male contraception have been researched?It's not that science hasn't tried to find an alternative form of male contraception - research has been ongoing for more than 40 years.While numerous clinical trials have shown promising results, these have yet to translate into a viable product.The difficulties lie in the complexity of the male reproductive system.The effects of the male pill need to:
be reversible (ie stop when contraception is stopped)
neutralise all sperm (of the millions men produce every day, only one is needed to fertilise an egg)
have no adverse impact on erections.The lack of progress has also had an impact on funding. The pharmaceutical companies Bayer and Organon have stopped research into hormonal versions of the male pill.
Hormonal contraceptivesRichard Anderson, professor of clinical reproductive science at Edinburgh University, has led a series of studies on the male contraceptive pill.His research found that when men are given the hormone progestogen, a component of the female pill, sperm production stops.But the body's supply of the male sex hormone testosterone is also cut, which reduces the man's sex drive and can cause other side-effects such as bone thinning. So testosterone injections are needed to counter this effect.In 2003 an Australian study reported a 100 per cent success rate with three-monthly injections of progestogen alongside an implant of testosterone that had to be changed every four months.More research is needed to develop a delivery system that men would use, for example by combining the two hormones into a single injection or implant.Other disadvantages of the hormonal treatments are the time it takes for them to take effect (up to three months) and the risk of side-effects, as with the female contraceptive pill.
Non-hormonal contraceptivesIn 2006 US and Italian researchers found a way to stop sperm developing in rats. The effect was reversible, with no ill effects.They believe that Adjudin, the molecule they used to prevent the sperm maturing, could be used to develop a drug that has the same effect in men. Before this can happen, more studies are needed to see whether Adjudin will work in the same way on human sperm.In London, scientists at King's College are working on a new hormone-free pill that gives a 'dry orgasm'. The man still climaxes, but the medicine stops any semen being produced.The man would take the pill four to six hours before sex, and its effect on fertility would reverse within 12 to 24 hours.But like all research into non-hormonal male contraceptives, this is still at a very early stage. Testing has yet to begin on animals.What form will the male pill take?At present it isn't possible to deliver male contraception in a single dose.The most likely form for the male pill will be a hormone implant with supplementary injections, then eventually a single long-acting implant.A tablet form of male contraception is a long way off.Will men take the pill and will their women believe them?An international survey of 4000 men and women revealed that two out of every three men said they would use the pill if it was available. Three-quarters of the women questioned said they would trust their man.While men may prefer a tablet form of contraception, John Guillebaud, professor emeritus of family planning and reproductive health at University College London says: 'I am in favour of a long-acting contraceptive implant for men rather than a pill.'Implants are better. Taking a pill every day with no slip-ups is not easy. We men just don't have the same motivation as women who would have to carry the baby.'If a man said he had an implant, the woman could check it out. All she needs to do is feel under his upper arm. It will be right there under the skin. 'Although the implant will be feelable, it won't be visible. I don't think many men would like to advertise their infertility every time they got into a swimsuit.'Who will use it? Professor Guillebaud believes the male contraceptive, in whatever form it eventually takes, will be used mainly by men in long-term relationships rather than for casual sex.There is a worry that anything that reduces the role of condoms among promiscuous men could increase the spread of sexually transmitted diseases. But the male pill will be new territory for everybody. Perhaps gaining a contraceptive implant will become a rite of passage for the teenager of the future.

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