Home fertility tests measure levels of follicle stimulating hormone (FSH) to determine fertility, but the cut off point they use is not accurate and many women measuring high levels of FSH actually go on to have babies naturally.
Levels of FSH predict the timing of menopause and can help doctors determine whether a woman is likely to conceive following assisted reproductive treatment, or if a prospective egg donor is likely to be fertile enough to donate eggs. However, no one knows if FSH can predict fertility or infertility in the general population.
Later Parenting Triggers Demand for Fertility Tests
Lots of women are choosing to delay parenting until they are in their 30’s. Once a woman reaches her 30th birthday, there is a marked decline in fertility and women aged between 30-45 have a risk of reproductive aging. It is harder for this age group to get pregnant and so the desire to monitor fertility levels has triggered the need for home fertility tests.
However, another hormone called antimullerian hormone or AMH may be a better indication of infertility than FSH.
"That is not to say that these tests are useless, but they certainly warrant further investigation," said lead study author Anne Z. Steiner, MD, MPH, assistant professor of obstetrics and gynaecology at UNC. "Our findings may mean that we need to go back to the drawing board and change the potential cutoff for infertility in the current tests, or perhaps we need to explore other tests altogether."
Women Tested Infertile Didn’t Have Difficulty Getting Pregnant
Anne Steiner and her team studied 100 women aged between 30 and 45 who had stopped using birth control. Their levels of estrogen, FSH and AMH were measured. They also took into account the couple’s intercourse patterns. Using the same criteria as current home fertility tests, they found one quarter of the women had abnormal FSH levels that would be considered infertile, but after the women were followed up for six months it was found that they didn’t have any more difficulty in getting pregnant than the other women in the study.
When they raised the threshold of the test to a higher value of FSH, they did find an association with infertility. This is because high levels of FSH indicate that restricting feedback from the gonad is absent, leading the brain to produce unrestricted amounts of the hormone. This is often a sign of the menopause.
“It may be that this test can pinpoint infertility”, said Anne Steiner, “but we need to uniquely define where that cut off is going to be.”
AMH is superior in predicting fertility but it can only be measured in blood and not in urine and the blood test has not been approved for clinical use but the hormone may provide a more accurate fertility test for the future.
Source: National Institutes of Health, Study authors Anne Steiner, Amy H. Herring, PhD and Steven Hoberman, MPH, UNC; Frank Z. Stanczyk, PhD, University of Southern California; and Donna D. Baird, PhD, National Institute of Environmental Health Sciences.