Pregnancy tests carry a serious amount of weight. So, of course, if you’re planning to take one, you want to make sure you’re getting the most accurate results possible.
With that, it’s only natural to wonder, when is the best time to take a pregnancy test? How soon is too soon? Does the time of day you take it even matter?
Here’s everything you need to know about pregnancy tests, including the answers to those questions as well as how they work and how reliable at-home tests can be.
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Meet the experts: Lauren Streicher, MD, is a clinical professor of obstetrics and gynecology at Northwestern University Feinberg School of Medicine.
Christine Greves, MD, is a board-certified ob-gyn at the Winnie Palmer Hospital for Women and Babies.
Asima Ahmad, MD, is a reproductive endocrinologist and co-founder of Carrot Fertility.
Mary Jane Minkin, MD, is a clinical professor of obstetrics and gynecology and reproductive sciences at Yale School of Medicine.
How At-Home Pregnancy Tests Work
Every pregnancy test is slightly different, but they’re generally looking for the same thing: the presence of human chorionic gonadotropin (hCG), the hormone produced by the placenta during pregnancy, says Lauren Streicher, MD, a clinical professor of obstetrics and gynecology at Northwestern University Feinberg School of Medicine.
“HCG can be detected in blood and urine around 10 to 14 days after conception,” she explains. “HCG levels typically double every 72 hours until peaking at eight to 11 weeks of gestation.”
Urine tests are the most common ones (and what you’d buy online or at your local drugstore), and the way these work is simple. They contain a special piece of paper that reacts when it detects hCG, says Christine Greves, MD, a board-certified ob-gyn at the Winnie Palmer Hospital for Women and Babies. You’ll usually see a double line, a plus sign, or the word “pregnant” when it’s positive, she adds.
If you have a blood test, your doctor will take a sample of your blood and send it to a lab, which will then determine how much hCG is in your blood, Dr. Greves says.
At-Home Versus In-Office Pregnancy Tests, Explained
Pregnancy tests fall into two categories: at-home urine tests and the in-office blood test.
At-home urine tests have different thresholds for the level of hCG they’re looking for, Dr. Ahmad says. “Some tests will only turn positive with higher levels of hCG whereas some can detect lower levels,” she says. “The interesting thing is the price of the test doesn’t always correlate with the hCG detection level. You can find some very cost-efficient home hCG tests that can detect hCG at low levels.”
The best way to find out how sensitive the test is is to read the language around how soon you can use it. A test that says it can detect pregnancy up to six days before a missed period, for example, generally has a lower hCG threshold than one that says it can detect it up to three days before your missed period, Dr. Greves says.
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Doctors will also likely confirm a pregnancy with a urine test, Dr. Greves says, adding that a blood test may be used if it’s very early in your pregnancy or if you or your doctor suspects you may have an ectopic pregnancy (which is when a fertilized egg implants and grows outside of the uterus). “The most accurate test is a blood test, as that can detect the lowest levels of hCG,” adds Asima Ahmad, MD, a reproductive endocrinologist and co-founder of Carrot Fertility.
How soon can you take a pregnancy test?
The earliest a test can detect the hormone in urine is about the six days before the day of the menstrual period that would be missed, says Mary Jane Minkin, MD, a clinical professor of obstetrics and gynecology and reproductive sciences at Yale School of Medicine. But, she notes, not *all* tests will let you know that early. “The standard ones will turn positive usually a day or two around the period being late,” Dr. Minkin says. Again, just read the label to find out what you’re dealing with.
But Dr. Ahmad stresses that pregnancy tests are the most accurate the closer to your missed period you take them. “One thing to keep in mind with all of this—and I think something that many of us are guilty of—is don’t test super early,” she says. If you test too early, you could end up with a false negative test, Dr. Ahmad says—meaning, you actually are pregnant but hCG isn’t at a detectable level yet.
When is the best time during your cycle to take a pregnancy test?
In a perfect world, you’d hold off to test until the day of your missed period, Dr. Streicher says. That can mean testing the morning that your period is due or, if you want to make sure you don’t use a test right before you get your period, you can give it a whole day to make sure you did, in fact, miss your period.
“To avoid false negatives and undue stress, try to hold off on testing until the recommended date, which for most pregnancy tests is 14 days after ovulation or on the day of expected menses,” Dr. Ahmad reiterates.
What time of day is best for a pregnancy test?
If you’re going the home pregnancy test route, it’s best to take a test when you wake up, Dr. Streicher says. This, she points out, is “when hCG levels are concentrated in the urine from overnight.” (Later in the day, your pee is likely to be a little more diluted.)
If you take a test in the afternoon or evening, you won’t necessarily get incorrect results, but there may be a higher risk of a false negative if you’re still early on in your pregnancy, Dr. Greves says.
If you’re getting an in-office blood test, “a blood test is not dependent on time of day,” Dr. Streicher says.
To sum up, the best time to test for the most accurate results is when you’ve actually missed your period. But signs like nausea, fatigue, vomiting, peeing more, having food aversions or cravings, and sore breasts can also be tip-offs that you could be pregnant, Dr. Ahmad says.
Pregnancy Test FAQs
How accurate are home pregnancy tests?
Every test is slightly different and the time you take it matters, too, Dr. Greves says. Many tests claim to be 99% accurate, but research from the Washington University School of Medicine in St. Louis found that up to 5% of tests return a false negative. If you received a negative pregnancy test result, but you feel like you’re pregnancy, Dr. Greves recommends testing again in a day or two.
What does it mean if I have a faintly positive line?
It could mean that the results are negative, or it could be that you’re pregnant but it’s so early that hCG levels are low (giving you a faint line instead of a bold one), Dr. Ahmad says. In this situation, you’ll want to test again in a day or two.
Korin Miller is a freelance writer specializing in general wellness, sexual health and relationships, and lifestyle trends, with work appearing in Men’s Health, Women’s Health, Self, Glamour, and more. She has a master’s degree from American University, lives by the beach, and hopes to own a teacup pig and taco truck one day.
