The imminent launch of the first contraceptive pill which promises to free women from the constraints of menstruation has pitched specialists on both sides of the Atlantic into a battle over what is "natural" and safe.
Lybrel, the first pill designed to eliminate the fertility cycle, putting an end to the mood swings and discomfort associated with periods, is expected to win a licence from the Food and Drug Administration in the US this month. In the UK, where it will be marketed as Anya, the US manufacturer Wyeth has applied for a licence which it expects to be granted next year.
The drug is designed to be taken continually unlike other oral contraceptives which are taken for 21 days a month with a break of seven days during which the woman has her period, preserving, albeit artificially, the biological rhythm.
The argument about whether the latest lifestyle choice to be offered to women is good for their health has already begun. Writing in the British Medical Journal, Paula Derry, a health psychologist from Baltimore, questions the wisdom of menstrual suppression and argues it is unnatural and potentially damaging.
Long-term safety has not been established and the argument that menstruation is obsolete is "illogical and unscientific", she says.
Her stance is supported by research in the US which has found many women view their periods as symbols of fertility and health. Rather than loathe them, they have a complex love-hate relationship with them.
But Christine Hitchcock, the director of the Society for Menstrual Cycle research, told The New York Times: "My concern is that the menstrual cycle is an outward sign of something that's going on hormonally in the body.
"[I worry about] the idea that you can turn your body on and off like a tap."
The same hormones that control the menstrual cycle act on the brain, bones and skin and the long-term effects of suppressing them were unknown, she said. "You need to think whether there are consequences for the whole body that we don't know about," she said.
In the UK, Professor Anna Glasier, 56, head of sexual health in Lothian, said the only virtue of menstruation was to reassure a woman that she was not pregnant and there was no other justification for putting women through the pain and misery of it. When she was on the contraceptive pill, she had taken it continuously and would advise other women to do the same, she said.
Research by Wyeth in the US has shown that nearly two thirds of women surveyed said they would be interested in giving up their periods. Gynaecologists argue that there is no reason why women should continue to suffer the pain, discomfort and emotional disturbance associated with menstruation.
When the contraceptive pill was first introduced in the 1960s it could have been designed to eliminate the fertility cycle. But there were no simple pregnancy tests available and scientists believed women would want the reassurance of a monthly period as proof that they were not pregnant.
Church leaders were worried about its impact on promiscuity and manufacturers of the pill felt that to mimic the natural monthly cycle as closely as possible would make it more acceptable.
David Archer, professor of obstetrics and gynaecology at Eastern Virginia Medical School led a study of Lybrel published in the journal Contraception. He said: "There is a rising tide of awareness and discussion on this issue [of eliminating periods]. But it will always be predicated on what women want and are prepared to tolerate.
"What we have done is taken an oral contraceptive and tweaked it to give women another choice."
A spokeswoman for the Family Planning Association in the UK said they welcomed more choice in contraception for women.
"Some women do not like the inconvenience of periods but others use them as a way of checking they are not pregnant," she said.
Is menstruation obsolete?
Yes, says Professor Anna Glasier, head of sexual health, Lothian
"When I took the pill I took it continuously. Who wouldn't? Who would want periods? The idea that menstruation is normal is wrong. Since time dawned most women have been pregnant or breast feeding or post-menopausal - so they didn't have periods. Also, the idea that the period you have when you are on the pill is natural is also wrong. The pill turns the ovaries off and the period you have is a fake. The thing to worry about is the increased risk of deep vein thrombosis on the pill - but there is no evidence that a seven-day break each month makes any difference."
No, says Paula Derry, health psychologist, Maryland, US
"If it is more common today to have monthly periods than in the past that doesn't mean it is unnatural. We know that menstruation is what naturally occurs when women don't become pregnant. A menstruating woman is a healthy, probably fertile woman - whereas unhealthy, malnourished or massively stressed women are more likely to skip periods. Menstrual suppression is unnatural. A drug chronically over-rides the physiological changes associated with the menstrual cycle creating a hormonal environment that is not found in nature."Reuse content