A Popular Fertility Test May Not Be Accurate
A commonly used fertility test may not be an accurate predictor of future pregnancy, according to new research.
The findings, published in the Journal of The American Medical Association (JAMA), bring into question the efficacy of the AMH (Anti-Mϋllerian Hormone) test, a procedure that determines a woman’s “ovarian reserve” – the number of eggs she has.
The AMH test has been widely regarded as a predictor of future fertility: The higher the number of eggs, researchers have thought, the likelier a woman is to get pregnant naturally, without “assisted reproductive technology” (ART) such as IVF (in-vitro fertilization).
In the study, investigators at the University of North Carolina at Chapel Hill followed 750 women, age 30 to 44, without a history of infertility. They adjusted for age, body mass index, race, current smoking status, and recent hormonal contraceptive use.
The subjects provided a blood and urine sample for the test, which also measures the hormones FSH (follicle-stimulating hormone) and inhibin B. Research has linked levels of these hormones with ovarian reserve.
As expected, the university’s School of Medicine said in a news release, “AMH levels decreased and urinary FSH values increased with increased female age. However, after accounting for differences in age, women with a low AMH value (low ovarian reserve) were just as likely to get pregnant within a year of trying compared women with a normal AMH value (normal ovarian reserve).” After six cycles of attempts, the difference in achieving pregnancy between the two groups was three percent; after twelve cycles of attempts, the difference was nine percent. In the JAMA study abstract, the researchers called the difference “nonsignificant.”
The researchers defined “pregnancy” as a positive pregnancy test.
Lead author Dr. Anne Steiner said that proof of the AMH test’s effectiveness has been lacking although it is widely used. (At least one company is now offering an online version of the test.) “Over the years, they’ve worked their way into being in the mainstream without evidence,” said Steiner, a reproductive endocrinologist at the University of North Carolina School of Medicine, according to the website Statnews.
The study conclusion was stark: “Based on our results, we should caution women from using AMH or FSH levels to assess their fertility,” said Steiner in a news release from the university’s school of medicine. “Low ovarian reserve does not indicate that a woman will necessarily have difficulty conceiving naturally.”
But she cautioned against using the test results as an indication that delaying pregnancy is a good option: The older a woman gets, the less likely she is to conceive naturally, Steiner said in the news release. So a decision to postpone pregnancy shouldn’t be made on the basis of an AMH test result.
“Age still remains the best predictor of a woman’s reproductive potential. Therefore, tests indicating normal or high ovarian reserve should not be used as justification to delay attempts to conceive.”
Steiner is the primary investigator for the UNC-Chapel Hill site of the Reproductive Medicine Network, which runs infertility clinic trials. For more information, visit www.uncfertility.com.