Women who take the contraceptive pill are in danger of permanently dampening their libido, according to a team of scientists in the United States.
Researchers at Boston University Medical College found that women who take the pill regularly have much lower levels of the hormone that drives sexual desire. The hormone remains suppressed even when they come off the pill.
The scientists behind the study called on GPs to warn women of the potential danger before prescribing the pill and criticised the medical profession for handing out oral contraceptives ”like candy”. But the Royal College of General Practitioners moved to reassure women that the pill was safe and encouraged them not to shun the pill in light of the findings.
Claudia Panzer and Irwin Goldstein tested 124 women being treated for sexual dysfunction. Half used the pill regularly, 39 had just come off the pill and 23 had never used oral contraceptives.
The scientists analysed blood samples from all the women for traces of a substance called sex hormone binding globulin (SHBG). The pill makes the body over-produce SHBG, which mops up testosterone, the hormone that drives sexual desire.
The blood tests showed that women who regularly used the pill had very low levels of testosterone, but four times as much SHBG than women who had never been on the pill.
Further blood samples from the women who had come off the pill revealed that four months later, levels of SHBG had dropped but were still nearly double that found in women who had never taken oral contraceptives.
”What concerns us most is that the levels of SHBG show no sign of dropping any further in those who came off the pill,” said Panzer.
”You would expect levels to drop back to normal after about six weeks, but the worry is that these women will always have more. That means they will have very low testosterone, which has huge implications for their sexual function.”
The researchers fear that levels of SHBG, which is produced by the liver, might be permanently raised in women who go on the pill, regardless of whether they later stop.
”I find this scary. Birth control pills are handed out like candy, but no one is told what the pill might do for a woman’s sexual function,” said Panzer. ”Doctors who prescribe the pill should tell women about the effect it might have.”
The pill is the most common contraceptive in Britain and is used by 26% of women between the ages of 16 and 49. The study, which is reported in New Scientist on Thursday, was presented at the American Association of Clinical Endocrinologists in Washington DC last week.
Dr Mayur Lakhani, chairperson of the Royal College of General Practitioners, said: ”I want to reassure women about the safety and efficacy of the contraceptive pill and to stress that there’s no need to stop taking the pill as a result of this study. Loss of libido is a recognised side effect but in the experience of GPs and practice nurses this is uncommon among most women.
”I am unconvinced by this study; there is no cause for alarm. Women receive counselling as a matter of course when prescribed the pill.”
Lakhani added that anyone worried should discuss their concerns with their practice nurse or GP. – Guardian Unlimited Â