A new tablet has been experimented that can suppress menstruation for as long as a woman wants should be available within a few years.The tablet, which blocks the action of the hormone progesterone, appears to be a safe and reversible way of stopping the monthly menstrual cycle. Two versions of the new pill have just passed their first test in animals, with the results published by American and German scientists in the latest issue of the journal Human Reproduction.
It could not only benefit women who find having a period uncomfortable or inconvenient, but also bring relief to sufferers of abnormal conditions such as excessive bleeding or endometriosis (where the uterine lining escapes to other organs). As excessive bleeding is one of the major reasons women undergo hysterectomy, the treatment may also reduce the need for this surgical procedure.
Most existing ways of blocking periods depend on synthetic versions of the naturally-occurring hormones oestrogen and progesterone, but these are not tolerated by all women, and are often unreliable at blocking menstruation over longer timespans.Taking the contraceptive pill continuously - without taking the monthly cycle of sugar pills - can delay periods in most women, but usually only for about four months.
The new drugs were tested on rhesus macaque monkeys because the bodily mechanisms controlling their periods are identical to those of humans. This means the treatments should be available to women very soon, the researchers say. All animals treated, regardless of the dose given, remained in good health and returned to normal cylces 14 to 40 days after treatment stopped. "The modern woman is accustomed to having control over her reproductive functions and menstruation is one function that many women would like to control," says author Dr Robert Burns, from the Oregon Regional Primate Centre in the United States.
As well as blocking the effect of progesterone, both of the new drugs stop the action of naturally-occurring oestrogen on the uterus. This is important because oestrogen without progesterone may result in a build-up of the uterine lining, which can lead to cancer and/or excessive bleeding.
Our ancestors, without access to good nutrition, reliable contraception, and infant formulas, spent far more of their lives either pregnant or breastfeeding. This meant they probably had only 40 periods over the course of their lifetime, compared to the 300 to 400 most modern women experience.