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Ovulation findings could help infertile women: Sask. biologist
Last Updated Tue Jul 8 21:51:31 2003

SASKATOON-- Researchers in Saskatchewan have discovered women can ovulate more than once per cycle. The findings could explain unexpected pregnancies and why contraceptives don't always work.

The study suggests women may be able to get pregnant at various times during the menstrual cycle. On the other hand, it's bad news for those using natural family planning methods.

"We have a word for people that use the rhythm method," quipped reproductive biology Professor Roger Pierson of the University of Saskatchewan. "We call them parents."

Scientists had thought up to 20 follicles grow at the beginning of each cycle. They believed only one egg reached maturity and was released for fertilization, about midway through the cycle.

Angela Baerwald gave daily ultrasound tests to 63 women, aged 18 to 40 as part of her PhD research.

When the team analysed the monthly ultrasound images, they concluded that with many women, follicles - which contain the egg - develop in two or three major waves.


The researchers found about 40 per cent of women have the potential to ovulate more than once during a cycle.

Lois Hertzum-Larsen of Saskatoon volunteered for one of the initial studies more than 10 years ago because she wanted to have a baby. She said it's a relief to find out not everyone ovulates according to the theories in medical text books.

"It's very encouraging and I look forward to seeing how they're going to improve their high-tech infertility treatments," she said.

Pierson plans to study both the infertility and contraceptive applications of the research.

Gynecologist Dr. John Lamont of McMaster University in Hamilton, Ont., called the study startling. He said it may explain why current in vitro fertilization methods don't always work.

The study appears in the journal, Fertility and Sterility.

Written by CBC News Online staff


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