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A CONTRACEPTIVE ring could make life easier for women worried about the
hormone levels in their pill—or those who simply forget to take it.

The device, a flexible plastic ring just over 5 centimetres in diameter and 4
millimetres wide, is folded and inserted into the vagina once a month. The ring
springs back into shape around the cervix and releases hormones over the next
three weeks until a period is due. These hormones stop eggs from maturing and
being released, and thicken cervical mucus to make it tough for sperm to get
through. The inventors say you don’t have to remember to take a pill every day,
and the ring would be ideal for women who’d rather not have periods at all.

Women can easily insert and remove the contraceptive rings by themselves.
“It’s good for women who aren’t squeamish about their own bodies,” says Frances
Perrow from Marie Stopes International, a family-planning centre based in
London.

Frans Roumen, a gynaecologist running tests on the ring for pharmaceuticals
company Organon in the Netherlands, says the ring could also be used by women
who choose not to have periods at all. Doctors don’t think this carries any
health risk. “You can use the pill continuously without problems,” says Roumen.
Forty years ago they thought it would be reassuring to have periodic bleeding.
“It’s very bizarre,” he says. Periods give women a chance to confirm that
they’re not pregnant. But that can be done with a pregnancy test.

“I think in future women can have a ring once a month and stay on them
continuously,” says Roumen.

Researchers have worked on vaginal rings before, but couldn’t get plastic to
slowly release both progestogen and oestrogen. Surgically implanted
contraceptives use a similar technology but only release progestogen into the
blood. That can cause annoying irregular bleeding. Organon solved the problem by
impregnating a central core of ethylene-vinyl-acetate with the hormones. A skin
of the same plastic lets both hormones leak through at a constant rate. “It is a
big breakthrough,” says Perrow.

Local delivery means the ring need only release 15 micrograms of oestrogen a
day— half the amount in oral contraceptives. This is good news because
oestrogen has been associated with an increased risk of thrombosis, although no
one yet knows if the ring will be completely safe for women in high-risk groups.
Roumen says the ring can be left in during sex without problems, or taken out
for up to three hours.

In trials with 1145 women over one year, only 6 women using the ring became
pregnant. This failure rate of less than 1 per cent makes it about as effective
as taking the pill regularly. But in reality about three per cent of women using
the pill get pregnant every year, usually because they forget to take it. The
ring is awaiting approval in Europe but should be available in the US this year.