A simple blood test to predict onset of menopause may not be far off.
Anti-Mullerian hormone (AMH) levels in the blood could tell when fertility would start declining, says Queensland University of Technology statistician Professor Malcolm Faddy.
For the AMH levels reflected the number of small follicles present in a woman's ovaries, which are responsible for the supply of eggs for ovulation. And depletion of the stock of follicles leads to menopause.
Professor Faddy, from the QUT's School of Mathematical Sciences, is a co-author of a study with researchers from the Netherlands that looked at the relationship of a reproductive hormone and menopause.
He said, "The study measured AMH levels in blood samples from a group of healthy fertile women, using the data to determine a model of age-related change in AMH levels.
"We then used this model to predict age at menopause via a critical AMH threshold level.
"Prediction of menopause has been problematic since it is retrospectively defined as the cessation of menstruation for at least 12 consecutive months.
"But with prediction it becomes possible to forecast when natural fertility is in decline."
Faddy said there was a wide variation in the age of menopause which for most women occurred between 40 and 60 years of age.
"But we know from studies of natural populations where the timing of having children is not influenced by contraception, that natural fertility drops off some 10 years before menopause," Professor Faddy said.
"This means that with the variation in menopausal age some women could become infertile as early as their 30s.
"It is then difficult to become pregnant without artificial intervention."
Professor Faddy said that prediction for women younger than 30 remains difficult because AMH levels did not show much of a decline till after this age.
He said the researchers in the Netherlands were following a group of women to test the validity of the predictions.
After validation of the model, their work could lead to a blood test which assessed the level of AMH being used to estimate the number of years of fertility left.
The study will be published in the June 2008 edition of the Journal of Clinical Endocrinology and Metabolism