I thought that men are fertile throughout their lives, but women lose their fertility at menopause. What determines when a woman enters menopause: are her ‘eggs’ gone, has her biological clock ‘finished’?
A question that was ‘hot-topic’ in my recreational women’s volleyball circle!
Answer
Dear Pieter,
most studies agree that a woman’s fertility is indeed limited, unlike male fertility. At birth, a girl has about 6 million eggs, of which only 400,000 remain at puberty. In the fertile period (puberty to age 35), about 1000 follicles are consumed each month, usually including one dominant follicle released at ovulation. After the age of 35 there is an even faster consumption of follicles and the egg cell quality also decreases from this age. So about 10 years before the onset of menopause (on average around age 45), signs of ‘ovarian exhaustion’ are already noticeable. If you do the math, only about 400 follicles are eligible for fertilization and the other 99.9% are lost.
Recent, controversial studies question this established theory. According to these researchers, women are not born with a finite number of eggs, but there is still some production during life. However, these studies are currently scarce.
Hopefully this has answered your question and that of your fellow volleyball players,
regards
Ilse Delbaere
Answered by
dr. Ilse Delbaere
Obstetrics, midwifery, human embryo implantation, placentation, multiple births
http://www.ugent.be
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