IT MIGHT be possible to predict how many years a woman has left before the menopause based on an ultrasound measurement of the volume of her ovaries.
That鈥檚 the argument of Hamish Wallace of the Royal Hospital for Sick Children in Edinburgh, UK, and Thomas Kelsey, a mathematician at the University of St Andrews. 鈥淲e now have the potential to be able to tell a woman how fast her biological clock is ticking and how much time she has before it will run down,鈥� says Wallace.
The pair assume that the variation in the age of menopause depends on the number of eggs a woman has at birth 鈥� a plausible assumption but one that must be tested, Kelsey says. If so, counting the number of eggs a woman has remaining would enable the age of her menopause to be predicted.
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The number of eggs cannot be counted directly, but Wallace and Kelsey argue that their analysis of published studies shows there is a strong link between the volume of the ovaries and the number of remaining eggs (Human Reproduction, vol 19, p 1613).
Measuring ovarian volume with an ultrasound probe inserted into the vagina (a quick procedure already widely used in fertility clinics) should thus reveal if, for example, a 40-year-old women has 15 years left before the menopause, or just 9, give or take a year or two.
鈥淎t best, it鈥檚 a rough and ready approximation,鈥� says Kelsey. The pair are now planning studies to validate the proposed method, and hope other fertility clinics will try it as well. 鈥淚 must emphasise that it is too early to roll this test out for all women,鈥� says Wallace. 鈥淔urther research is required to evaluate it.鈥�
The technique will not work for women who are taking the pill, which reduces the volume of the ovaries. Women would probably have to wait about three months after coming off the pill, Wallace says.
A more serious problem is that the method cannot reveal for how long a woman will continue to produce viable eggs. The percentage of eggs with chromosomal abnormalities increases rapidly after the age of 40 (see 快猫短视频, 12 June, p 6). Women who leave having children too late could fall into this trap, says Kelsey.
Despite these limitations, the more widespread use of transvaginal sonography, as the ultrasound scan is called, could have another benefit. Kelsey says it should help doctors spot conditions such as polycystic ovaries and ovarian cancers.