Menstruation never suited Angela Fontaine. Between swimming, fishing, raising a nine-year-old and working 12-hour shifts as a nurse, there wasn't enough time to waste a few days each month feeling bloated and cranky. So when the 29-year-old learned she could do away with her periods - or at least most of them - she jumped at the chance.

The opportunity came in the form of a clinical trial for a new type of birth-control pill called Seasonale. Released this month in the US and expected to arrive in the UK next year, Seasonale - which gives women just four periods per year - is the first birth-control pill designed to overhaul the monthly cycle. There is a small range of other period-suppressing contraceptive methods about to come on the market here, all of which cause irregular menstruation in some users, or may stop it entirely - but Seasonale promises a newly predictable way of cutting down on periods.

Like traditional birth-control pills, Seasonale contains synthetic oestrogen and progesterone. The difference is women will take 84 days of the hormones - as opposed to 21 - before starting their seven-day course of placebos, and they will get their periods just once every three months. "I felt much better on it, and I didn't have any side effects," says Fontaine, who now says she'll never go back to monthly periods.

Fontaine is far from alone. According to new research, two-thirds of women say they would happily forego menstruation if the method were safe. And their dreams may soon be realised, as many experts expect the next step will be a pill designed to do away with periods altogether. In recent years, more and more women have been opting out of their periods - some on the advice of doctors to relieve painful periods, and others who simply prefer to avoid the hassle - by taking the pill non-stop and skipping the seven days of placebos provided.

But as menstrual suppression goes mainstream, questions are mounting: is it safe? Is a woman's natural rhythm best left alone? Are periods a central component of female identity, or are they merely an impediment - as treatable as bad eyesight?

According to Dr Leslie Miller, from the University of Washington, the uterus was not designed to bleed every month. Historically, says Miller, who has suppressed her own period for years, women began their periods later, and then spent many years pregnant and breast-feeding. "One hundred years ago, the average woman had fewer than 50 periods during her life," Miller writes. "Now, the modern woman could have 450."

Miller also points out that the periods women have on the traditional pill hardly constitute true menstruation. "It's a fake period," she says. In fact, when the pill was first developed in the 1950s, its inventors acknowledged that women taking the drug did not need to have periods every month. But they settled on a monthly cycle - 21 days of hormones, followed by seven days of placebos - to mimic a woman's natural cycle. It was a decision guided more by public relations than science.

Still, not everyone is convinced that the era of the period is coming to an end. Susan Rako, psychiatrist and author of No More Periods? The Risks of Menstrual Suppression, calls the suppression of periods "the largest uncontrolled experiment in medical history". Rako says that women who eliminate their periods can develop symptoms of testosterone deficiency, such as loss of libido, muscle tone, energy and the putting on of weight.

And then there are worries about more pernicious health problems. Since long-term use of oestrogen products has been linked to an increased risk of breast cancer, some doctors fear a daily dosage of the hormone could be particularly harmful. And Rako says that nonstop pill usage could increase the odds of contracting cervical cancer among women who have the human papilloma virus, a not uncommon sexually transmitted disease.

"The menstrual period is a somewhat complicated process," adds Dr Edward Kleiber, of the University of Massachusetts. "We have been manipulating it as though we could do it without any serious implications." Tampering with a woman's natural hormonal balance is no small risk, says Kleber, pointing to the recently publicised risks associated with HRT.

But the sociological questions associated with stopping periods may be even more divisive. Periods have become interwoven with many women's identity; a badge of honour connoting health and fertility and communion with nature - or a curse, depending on whom you ask.

Jordan Rosenfeld, 29, says she would never voluntarily eliminate her own period. "It's an event I have known for more than half my life," she says. "There's a certain amount of my feminine identity attached to having my period." And although Rosenfeld suffers from moderate cramps, she describes a certain satisfaction in feeling the workings of her uterus on a monthly basis.

In Rako's view, toying with a woman's emotions and libido - both of which she says rise and fall throughout her cycle - amounts to meddling with her very femaleness. "It is appalling to think some parents might petition their doctor to give their teenage daughters nonstop birth-control pills," she says. "Girls need to get to know their bodies, their rhythms and their sexuality."

Dian Campbell, 48, who has suppressed her periods for two years, counts herself among those who endured needless pain for too long. After struggling with severe cramps and flu-like symptoms every month, Campbell's doctor recommended she take the pill with no placebos. "I am so happy to not be spending a couple of days a month in [misery], psychologically, emotionally - to say nothing of the physical," Campbell says. "I was certainly not cherishing any of that womanly stuff."

Sandra Wooten, 41, also says she wasted too many years enduring monthly pain. After taking drugs, painkillers and eventually having two operations on her uterus, Wooten finally found salvation when her doctor suggested menstrual suppression. Two years later, pain-free and period-free, Wooten wonders how - and why - she withstood those years of pain.

Then there is the feminist case to be made for stopping periods, and it is one that the backers of Seasonale are promoting. Some studies show that period pains are a leading cause of missed school days and workdays for girls and women. And women are less productive during their periods. "When you're talking about a glass ceiling, I wonder if women walk past the Kotex to get there," says Nelson.

Recalling the case of a 12-year-old whose severe cramps caused her to miss several days of school each month and fall behind in classes, Nelson says there's a fine line between exploring your femininity and needless torture. "What if guys had clumps of blood coming out of the ends of their penises? We would have come out with this a decade ago." Maybe so. But for women like Angela Fontaine, the advent of Seasonale is better late than never. And as the new pills make their way into chemists, each woman will have to decide for herself: to bleed or not to bleed.

· A longer version of this article can be read on www.salon.com