A contraceptive pill that promises to end the misery of menstruation for millions of women has been proved safe and effective for the first time.
The medicine, called Lybrel, was taken every day for a year and halted periods in more than half of the 2,000 women who used it.
It is the first pill specifically designed to eliminate the fertility cycle which many regard as central to womanhood. Ordinary oral contraceptives are taken for 21 days a month, with a break of seven days during which the woman has her period, preserving the biological rhythm.
But some gynaecologists argue that there is no reason why women should continue to suffer the pain, discomfort and emotional disturbance associated with menstruation. They say it is easily eliminated and no different from treating the menopause with hormone replacement therapy or impotence with Viagra.
Lybrel is not yet licensed but its maker, the American company Wyeth, has applied to regulators on both sides of the Atlantic. It is expected to be launched in the US and UK next year.
David Archer, professor of obstetrics and gynaecology at Eastern Virginia Medical School, who led the study published in the journal Contraception, said: "There is a rising tide of awareness and discussion on this issue [of ending periods]. But it will always be predicated on what women want and what they are prepared to tolerate. What we have done is taken an oral contraceptive and tweaked it to give women another choice."
He said that when the contraceptive pill was introduced in the 1960s, it could have been designed to eliminate the fertility cycle. But no simple pregnancy test was available and scientists believed women would want the reassurance of a monthly period as proof they were not pregnant.
In 1977, the first trial of "extended use" oral contraceptives was conducted, in which women took the pill for months at a time. "The results showed the consumers liked it but the doctors didn't," Professor Archer said.
In 2000, two fertility experts from the Population Council of Mexico - Sarah Thomas and Charlotte Ellertson - delivered an impassioned plea in The Lancet for modern drugs to end menstruation.
They wrote: "At a minimum, it is a nuisance that requires planning, expensive sanitary supplies and paracetamol to avoid messy discomfort for about one week each month.
"In many cases, however, it has a far greater impact. Hormonal fluctuations accompanying the menstrual cycle have medical consequences that are largely ignored, women are expected to function as normal and minimal attention is paid to physical and mental discomfort."
The monthly period had been "mythologised and socialised" into being the unquestioned natural state for woman, they said.
Professor Archer said his study showed 58 per cent of women were free of periods after using the pill for a year. But the downside was some had irregular bleeding, which was unexplained. "This product is not for everyone. But for women wanting to suppress periods it is a good choice," he said.
A spokeswoman for the UK's Family Planning Association said it welcomed the extra choice for women. "Some do not like the inconvenience of periods but others use them as a way of checking they are not pregnant," she said.
An oral history
1930s Scientists found that steroid hormones, such as androgens, oestrogens and progesterone inhibited ovulation
1950s Experiments in the US using hormones to prevent pregnancy started in humans
1960 Enovid, the first contraceptive pill, approved by the US Food and Drug Administration
1967 Contraception including the pill was legalised in France
1999 The Pill is approved for use in Japan after safety concerns over its long-term use were finally dispelled
2003 Seasonale, the first three-month version of the pill, launched in the US, bringing less frequent periods
2007 Expected launch of Lybrel, first continuous dose oral contraceptive designed to end periods.Reuse content