If you’re actually trying to get pregnant, the time period you have to wait after ovulation to see if things, well, worked can feel like months. Conversely, if you’re on the missed period and panicking train, there is nothing more nerve-wracking than the few minutes you wait for an at-home pregnancy test result to appear. The reality is, even though pregnancy tests are more accurate than ever before, you won’t be able to get a result immediately after you have sex to find out whether you’re pregnant. We know, it may not be not as soon as you may have hoped.
“The earliest I would recommend taking a home pregnancy test is seven to 10 days after ovulation, and you should ideally have sex 24 to 72 hours prior to ovulation for the best chance to become pregnant,” says Lori Hardy, MD, obstetrician and gynecologist at Northwestern Medicine. “Taking a test earlier than that would possibly give a falsely negative result. Therefore, as far as how soon after sex you would be able to tell you were pregnant would probably be 10 to 14 days.”
However, you still may not get an accurate answer after that amount of time. Even in that timeframe, there still could be a falsely negative result, since hormone levels in early pregnancy can vary and the reliability of a home test depends on detecting a certain level of hormone, explains Dr. Hardy. “Many home pregnancy tests claim to be accurate as early as the first day of a missed period — or even before,” she says.
If you truly want the most accurate home pregnancy test result, you’ll have to be super patient. (One exception is if you know immediately after unprotected sex that you could potentially get pregnant, i.e. a condom broke. In that case, you can look into emergency contraception pills or an IUD, which can work from 72 hours to 5 days after sex.) For anyone who doesn’t mind getting pregnant or is trying, Dr. Hardy says you’re likely to get more precise results if you wait, at least until after the first day of your missed period.
And if you think going to your doctor’s office will result in a more accurate (or sooner) test results, you may be disappointed. “Urine pregnancy tests in the doctor’s office are not necessarily more reliable than sensitive home pregnancy tests,” says Dr. Hardy. “A blood test in the doctor’s office would be the most accurate for early pregnancy detection. In most cases, however, with the sensitivity of modern urine pregnancy tests, blood tests are generally not necessary for pregnancy detection.”
If you do take a test at home and feel like it may not be accurate, feel free to re-test. “If the initial test is negative, you can retest in 24 to 48 hours,” Dr. Hardy says. “Ideally, wait until the first or second day of a missed period for the most accurate results. If the test remains negative and you miss your period completely, that is the time I’d recommend seeing a doctor.”
And FYI, you can do a pregnancy test on a sample of urine collected at any time of the day, not necessarily first thing in the morning, adds Dr. Hardy. (Although urine at that time of the day is generally a bit more concentrated, so the hormone might be more easily detected early in pregnancy.) You may also be in the headspace of wanting to get the test over with and know the results already.
Bottom line: Take the test at least 21 days after you last had unprotected sex. “Some very sensitive pregnancy tests can be used even before you miss a period, from as early as eight days after conception, but as mentioned earlier, hormone levels may vary and the test depends on detecting the hormone level in your urine,” Dr. Hardy says. Waiting until that 21 day mark could give you the most accurate result, and put your mind at ease, whatever that result is that you’re hoping for.
A version of this story was published May 2019.
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