Юли 2003:

"Women may ovulate more than once a month, suggests a Canadian study that overturns conventional views on the human menstrual cycle.

The findings may explain why the rhythm method of contraception is so unreliable and could lead to improved, targeted fertility treatments in the future.

Ten per cent of the women studied released two eggs in the same month. And all the women examined by researchers at the University of Saskatchewan in Saskatoon, Canada showed at least two waves of maturing eggs in their ovaries in the same month.

Traditionally, it has been thought that ovulation takes place only once in every menstruation cycle. A growth wave of 15 to 20 egg-carrying cells called follicles occurs before ovulation. One follicle will become dominant while the others die off.

"It's been assumed until now that women have just one wave per monthly cycle, leading to one ovulation, but nobody has actually carried out detailed analysis before," said Roger Pierson, who led the study. "In fact, all the women in our study had at least two waves and 30 per cent of them had three."

http://www.newscientist.com/article.ns?id=dn3927