When you’re trying for a baby, it’s natural to be so excited that you want to pee on a pregnancy test as soon as you’ve done the deed. But test too soon and you might not get an accurate result.
A look at the pregnancy test section of your local drugstore will reveal boxes that claim to detect your pregnancy as early as six days before your missed period. While that might sound too good to be true, it is possible, says Ashley Gilman, a Toronto OB-GYN who specializes in reproductive endocrinology and infertility. “The pregnancy hormone should be present in your urine a few days before your expected period,” she explains.
Beth Taylor, a Vancouver-based infertility specialist, agrees that “early-detection” pregnancy tests are more than just a marketing angle. Though all pregnancy tests work by detecting a hormone called human chorionic gonadotropin (hCG), “some tests will have a threshold of 10 mIU/mL to call it positive, while others will have a threshold of 25 or 30 mIU/mL,” she says. She explains that early-detection tests use a lower threshold.
But this advanced knowledge will cost you: A single early-detection test is at least double the price of a conventional one.
The hormone hCG is manufactured by the placenta and first appears in your urine anywhere from 10 to 14 days after fertilization. But while hCG increases rapidly in the first few weeks, not everyone produces the exact same amount on the exact same timeline. Because of this and because it’s possible for your cycle to vary slightly from month to month, it’s not uncommon to get a false negative. “If you ovulated even just a day or two later than normal, a negative test might not actually be a negative,” says Gilman.
“The longer you wait for testing, the more accurate it’s going to be,” adds Taylor. She recommends waiting to test—at least until you’re expected period—to get the most accurate result possible.
To help minimize your odds of getting a false negative, Taylor says to test using your first urine of the day. Unless you have a tendency to visit the washroom frequently during the night, your hCG will be at its highest concentration in your first urine and give you the best shot at an accurate result.
If you test early and get a negative sign, hold off on reaching for that bottle of wine. “Until you get your period, you should at least assume that there’s a chance that you’re pregnant,” says Gilman, who recommends that you retest again on or closer to the date of your expected period.
But a positive test means you’re pregnant, says Taylor, who adds that there’s no need to retest.
If you’re tempted to skip an at-home test and head straight to the doctor’s office, think again. Taylor explains that a blood test might get you an answer a day or two earlier, but that’s only if the lab can turn your results around on the same day.
While both physicians agree that waiting to test until the date of your expected period is ideal, they understand that just might not work for some women. “For most women, there’s no harm in testing every day,” says Gilman.