You may or may not have heard about them, but homemade pregnancy tests are gaining momentum. Mommy bloggers have posted about them, recent YouTube tutorials have reached millions of views, and people have commented with their own DIY experiences.
Tests like these date back to long before medical breakthroughs. Ancient Egyptian women, for example, believed urinating on wheat and barley could determine pregnancy and the sex of the baby. Today, popular homemade pregnancy tests use other products found in your cabinets, including vinegar, salt, bleach, toothpaste, and Pine-Sol. The concept is pretty standard: mix your urine with the product, wait a while, and see if certain reactions indicating pregnancy like foam or color change have occurred.
The idea is these products are reacting to human chorionic gonadotropin (hCG), the hormone produced by the placenta during pregnancy that blood and over-the-counter pregnancy tests are able to detect.
The good news is homemade pregnancy tests are pretty much safe—although doctors advise against the bleach pregnancy test because it can create potentially harmful fumes. The bad news is experts don't believe they actually work.
"When you have a pregnancy test that has been validated and tested for accuracy, I know exactly what's being measured," says Carmen Wiley, Ph.D., a clinical chemist and president of the American Association for Clinical Chemistry in Washington, DC. "With these [homemade] pregnancy tests, it's not clear to me how they work."
Unlike home products, over-the-counter pregnancy tests contain "an antibody that's been designed to capture [hCG]," says Dr. Wiley. "Then there's usually a second antibody that comes along that emits a color, a detection."
So why does a reaction sometimes occur when mixing urine with home products? That probably has to do with urine pH, rather than the presence of hCG. The levels of pH can vary depending on individual physiology, diet, and medical conditions, such as diabetes, Dr. Wiley explains.
Even simply taking a homemade pregnancy test in the morning can play a role. "That's when your urine is most concentrated so that could lead to that kind of foaming in urine," says Amy Peebles, M.D., an in-house fellow at the American College of Obstetricians and Gynecologists in Washington, DC.
Taking a homemade pregnancy test for fun isn't an issue. But doctors warn that relying solely on those results can be a cause for concern.
"There could potentially be an emotional harm," says David Clay, M.D., an ob-gyn at Clinic Sofia in Minnesota. He says women who desire a pregnancy may be devastated by a false negative and vice versa. Even worse, pregnant women who saw a negative result may not take the proper next steps, potentially harming their fetus.
Andre Saad, M.D., adds that a woman could also be putting herself in danger. "There are circumstances where the knowledge of pregnancy is critical," says the director of gynecology at Syosset Hospital in New York. "If a woman were to rely on a homemade pregnancy test getting a negative result, she may think she doesn't have to worry about an ectopic pregnancy, which is potentially life-threatening." Ectopic pregnancy, or when the egg fertilizes outside the uterus, occurs in 1 out of 50 pregnancies, according to the American Pregnancy Association.
Why women use homemade pregnancy tests
Over-the-counter pregnancy tests are said to be about 99 percent effective. But with some of them costing $20 or more, homemade ones may sound more appealing. That's especially true, says Dr. Clay, for women undergoing fertility treatments who generally take more pregnancy tests than average. Opting for a pregnancy test from a discount store is a viable option.
"[All pregnancy tests] are testing the same thing," he says. "They just have different thresholds for how low they can detect." Some top-notch ones like First Response Early Result can pick up hCG levels of less than 10, while some dollar store ones may only be able to detect hCG close to 100. Yet a few days after a missed period, hCG levels, which rise quickly in early pregnancy, should have already hit that number, Dr. Clay adds.
Dr. Peebles agrees: "The urine pregnancy tests that you can get inexpensively are very reliable; they are the same ones that we use in an office…Those DIY homemade methods have absolutely no science behind them."