Modern women have 400 periods in a lifetime. Preventing them would spare many a monthly discomfort and may even save lives. So why don't we do it?

Imagine a world without periods. A world in which there are no premenstrual mood swings, no stomach cramps and no bills for sanitary supplies and painkillers. Gone are the days of struggling into work feeling like a bloated elephant whose insides are about to fall out; so are the mad dashes to the loo before it is too late.

Imagine a world without periods. A world in which there are no premenstrual mood swings, no stomach cramps and no bills for sanitary supplies and painkillers. Gone are the days of struggling into work feeling like a bloated elephant whose insides are about to fall out; so are the mad dashes to the loo before it is too late.

This is not fantasy. For all those women who have never quite forgiven men for not menstruating, equality is here. The curse was lifted long ago; we just don't know it.

According to an article published in the latest Lancet medical journal, menstruation can be eliminated with no adverse effects by taking the Pill continuously. And not only does suppressing bleeding do away with all the inconvenience and discomfort of periods, it actually has health benefits, according to the report's authors. Welcome to "one of medicine's best-kept secrets", as they put it.

Frequent ovulation contributes to anaemia, some reproductive cancers and heart disease. If periods were abolished, diseases caused by menstruation such as endometriosis would improve, and conditions such as epilepsy and arthritis would not worsen cyclically, claim the report's authors, Sarah Thomas and Charlotte Ellertson, from the Mexico office of the Population Council.

Having fewer periods may even prevent breast cancer. Last week's New Yorker magazine reports the findings of Malcolm Pike, who travelled to Hiroshima in 1981 to study why Japanese women have breast cancer rates six times lower than American women. It could not be down to genes because once Japanese women moved to the US they began to get breast cancer almost as often as their American counterparts. Pike put the difference down to the process of cell division which occurs in ovulation. Japanese women start menstruating later, eat less fat and therefore produce less oestrogen. Given that the Pill suppresses ovulation and the monthly tide of oestrogen and progestin, Pike concluded that it had the potential to be a powerful anti-breast cancer drug.

Why then should women be "driven loony by their lunar cycles" when there is such a simple solution which could even save lives?

Monthly menstruation for decades on end is, in fact, a modern phenomenon. Research among contemporary hunter-gatherer populations suggests that women in prehistoric times had far fewer periods. They most probably came into puberty later, had earlier first births, frequent pregnancies and breastfed for longer. In the Dogon tribe of Mali, where these factors still pertain, women menstruate about 100 times in total. Meanwhile, in industrialised nations, women can expect 400-plus periods in a lifetime.

Not only is so-called "incessant ovulation" abnormal in evolutionary terms, it is also ill-suited to the lifestyle of most modern women, believes Dr Andrew Prentice, consultant gynaecologist at Addenbrooke's Hospital, in Cambridge. He welcomes The Lancet's report, saying it is time we woke up to the Pill's real possibilities. "At the turn of the century women had perhaps 30 or 40 periods during the whole of their reproductive life," he says. "Now women are having more than 400. At the same time they are playing a much more important role in the workplace, often as the major breadwinner. Twenty years ago, when women were often at home, they could just curl up in a ball when periods came along. That is not the case now. Menstruation has such an impact on women's lives and yet there are ways it can be managed."

Taking the Pill for months on end rather than in the usual schedule of three weeks on, one week off, is the logical next step for women - provided they do not suffer risk factors such as being smokers or overweight, Dr Prentice says. "I frequently prescribe the Pill for three months at a time.There is no downside. Historically women wanted the reassurance that they weren't pregnant, but I think they are a bit more sophisticated than their mothers." He added that if more women chose the period-free path, there would be less need for hysterectomies, an operation normally performed in response to heavy periods.

In the US, a new brand of oral contraceptives called Seasonale is to be specifically marketed for continuous use over three months, and the drug company Organon has come out with an oral contraceptive, Mircette, that cuts the seven-day placebo interval to two days.

But will women buy it? Or will they reject the latest "lifestyle drug"? Perhaps the Pill's inventors were right when they thought women wouldn't feel "natural" if they didn't bleed monthly.

Thomas and Ellertson go to pains to point out that anyone who takes the Pill has already departed from the natural cycle. They dub the "withdrawal" bleeding "pseudo periods". No egg is released because the Pill suppresses ovulation, therefore no medical purpose is served. The bleeding was simply scheduled in by the Pill's pioneers, John Rock and Gregory Pincus, because they thought women would find it reassuring. They were also trying to please the Catholic Church: if women bled once a month on the Pill, surely they were not interfering with the normal rhythms of life.

Dr Prentice is bemused by the level of ignorance among some of his patients about the status of Pill periods and the need for them. "There is still a belief among many women that they have to have a period every month, which I find quite alarming," he says.

Mark Charnock, consultant obstetrician and gynaecologist at the women's centre at the John Radcliffe Hospital, Oxford, tells the same story. "Some women think it's really important to have a good, solid bleed," he says. "They think it gets rid of waste products, but it's not like if your bowels have become stuck and you can at long last clear them."

He too is in favour of going down the Thomas/Ellertson route. "I think women should be aware that they don't have to tolerate periods if they don't want to," he says. But, he added, the proposals do not take into account strong sentiments against the Pill. "It's all very well to say 'the low-dose Pill' but, from time to time, there are some very scary reports about its adverse effects so most women are not too keen on it."

Kate Law, who is head of clinical programmes at the Cancer Research Campaign, has no such fears about the Pill's safety, and jumps at the idea of taking it non-stop. "Personally I feel like going straight to my GP," she says. "With modern women being more active, periods have just become a pain in every sense of the word. I like horseriding and skiing, but periods stop me because I have to be an hour away from a loo. Actually, I'm rather annoyed with myself, given that I work in a medical area, that I haven't heard of this earlier."

On a professional note, Ms Law endorses the health benefits of taking the Pill continuously. "It is well known that the more times you ovulate the greater your risk of ovarian cancer," she says. There are currently 6,800 new cases of ovarian cancer each year in Britain.

Thomas and Ellertson admit that there is a pitfall to their proposal: that in a world in which the majority of women opted to suppress their periods, those who decided to menstruate naturally might face censure. "By extension," they add, "treating the cycle as something undesirable that routinely requires medical correction may give ammunition to those who would like to discriminate against all women, by barring them from high-paying jobs that require consistent performance around the month, for instance."

For such reasons the psychotherapist and feminist writer Susie Orbach felt they should never have written the article. Periods must be celebrated not suppressed, she argues. "I think it's appalling that The Lancet should be publishing this kind of material. The fact is that menstruation is a feature of women's reproductive life. People are very free and easy with the notion of mucking about with biology, but it well behoves us not to."

What is needed, in Orbach's view, is a shift towards accepting periods, not shunning them. "We think of periods as something terrible, a curse even, rather than something miraculous in nature," she says.

But for most women, mood swings and bleeding every month is a curse. If there is a pill to remove it, they just might swallow it.