Waiting to find out if you’re pregnant can be stressful. You can of course take a pregnancy test as soon as you
miss a period, but some at-home tests can even detect pregnancy a few days before your period is due. Blood tests performed at a doctor’s office are the best way to know for sure if you are pregnant, but they aren’t offered as standard. Your body needs time to increase the levels of pregnancy hormone in your body before you’ll get a positive pregnancy test. Here’s everything else you need to know.
How soon will a pregnancy test read positive?
When to take a pregnancy test really depends on the pregnancy test that you use. All pregnancy tests measure the amount of human chorionic gonadotrophin (hCG), the pregnancy hormone, in your body.
Home pregnancy tests detect the presence of hCG in your pee
(SOGC nd).
Some home pregnancy tests are more sensitive than others. A few even claim to be able to detect low levels of hCG four days before your period is due, or just seven days after conception.
How accurate are home pregnancy tests?
The sensitivity of a pregnancy test is described on the packaging as mIU/ml (milli-International Unit per millilitre)
(APA nd). Pregnancy tests range in sensitivity from 10mIU/ml to 40 mlU/ml. The lower the number, the earlier a test can detect pregnancy.
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If you test too early, even with a sensitive pregnancy test, the amount of hCG in your pee may not be high enough to detect
(Cleveland Clinic 2022). This might mean you get a false negative, which is when a test says you’re not pregnant, but then you find out you are.
How early can you detect pregnancy?
Most home pregnancy tests will give accurate results if you test at the time your period is due. For most people that’s about two weeks after you
ovulate. You could still get a negative result even if you wait to test until your period is due
(SOGC nd).
A pregnancy test may be negative for a few reasons. You may not be pregnant. Or, you may have ovulated later than you thought, so you are not as far along in the pregnancy as you expect
(APA nd). You may have tested too early, checked your results too soon, or taken the test at the wrong time of day. For the most accurate results, test first thing. That’s when your pee is more concentrated, which helps hCG to show up
(Mayo Clinic 2022).
Some pregnant people can have very low levels of hCG levels at the time of a missed period
(APA nd). If you have a negative result, but still don’t get your period, test again three days later. If you are pregnant then the levels of hCG may have built up enough by then to be picked up by the pregnancy test.
A
blood test can also detect hCG. Blood tests are more sensitive than pee tests. They can detect pregnancy as early as a week before your period is due
(Cleveland Clinic 2022). You will not be offered a blood test for pregnancy until after your period is due, and even then only if there is a medical need.
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