Many at-home kits used to predict a baby's gender, a woman's fertility, or a man's sperm viability lack solid data to confirm their accuracy, according to a new review of fertility and pregnancy tests.
A trio of researchers from Johns Hopkins Medical Institutions in Baltimore looked at dozens of products across a range of applications, including pregnancy tests, genetic screens, and various measurements used to determine when a woman is ovulating.
"A lot of them are good and serve a useful purpose," Dr Paul Brezina, one of the study authors, said, "but some are not, and may even have claims that are misleading to patients."
The researchers analysed the medical literature, searched online, and spoke with manufacturers to assess the quality of evidence available for each product. They published their results online in Fertility and Sterility.
Pregnancy tests more reliable
Common, over-the-counter pregnancy tests that measure hormone levels in urine are some of the more reliable products available, Dr Brezina and his colleagues found.
Pregnancy tests "have been subjected to the scrutiny of scientific investigation and have publicly mandated quality control measures aimed at ensuring their accuracy," the authors wrote.
The same was true for fertility monitors that use hormone concentrations to predict when a woman is ovulating. These include the ClearPlan Easy Ovulation Test Pack, First Response, Answer Quick, and Simple One Step Ovulation.
Positive reviews stop
A variety of other consumer products used to predict a woman's ovulation, such as tests that analyse saliva or vaginal secretions, failed to have reliable, independent studies confirming their accuracy, for instance.
The same deficiencies exist for products to identify a baby's sex, such as the Intelligender Prediction Test and the Best Baby Gender Test.
"We looked hard, and we couldn't find any data," Dr Brezina said.
Rebecca Griffin, the co-founder of Intelligender, said that independent groups in Australia and Mexico have tested the accuracy of her product, but their results have not been published yet. She said Intelligender's website will post the results in future.
Regardless, her company doesn't market its baby sex predictor based on accuracy.
Not seeking adequate care
"I wouldn't want anyone to buy our test assuming 100% accuracy," she said. Rather, the test is intended to be a fun way to "bridge the curiosity gap" and should not replace a doctor's assessment.
In some cases, a lack of accuracy could be harmful, said Dr Jackie Gutmann, a fertility specialist at Reproductive Medicine Associates of Philadelphia, who was not involved in the new review.
"The bigger concern with some of these tests is being falsely reassured, because (people who use the tests) won't seek adequate care quickly enough," Dr Gutmann said.
For instance, Dr Gutmann points out, at-home tests for follicle stimulating hormone can give a false sense of security if the test is inaccurate.
Dr Brezina and his colleagues were unable to determine the threshold level of hormone these products detect, and therefore, whether their sensitivity is adequate.
Costs also considered
The authors also considered costs in their review. For example, electronic temperature monitors, that help detect ovulation, can cost hundreds, but consumers could also monitor ovulation cheaply with a calendar and a regular thermometer.
In total, Dr Brezina said, would-be parents spend a billion dollars annually on at-home fertility and pregnancy products.
He said he and his colleagues received no funding for this study, except for their salaries at Johns Hopkins.
(Reuters Health, Kerry Grens, February 2011)