Pregnancy tests
When to take a pregnancy test for the most reliable result
How soon a home pregnancy test can work, why testing from your missed period is more reliable, and what to do after a negative or positive result.
Updated · 5 min read · General information, not medical advice
The wait before testing can feel endless, and testing early is tempting. Here’s how timing affects home pregnancy test results, and how to get the clearest answer.
How soon can a pregnancy test work?
Pregnancy tests detect hCG, which starts being produced around six days after fertilisation, once the embryo implants. Levels then rise quickly. According to the FDA, hCG can usually be detected in urine around 12 to 15 days after ovulation in a 28-day cycle.
Some tests are marketed as working several days before a missed period. They can, but sensitivity varies between brands — and testing earlier increases the chance of a negative result even if you are pregnant.
The most reliable time to test
- From the first day of your missed period. The NHS says most tests work from this point.
- A week or more after a missed period gives an even more reliable result. The FDA notes that some people who are pregnant won’t get a positive on the first day of a missed period, often because of irregular cycles or miscalculated dates.
- If you don’t know when your period is due, the NHS suggests testing at least 21 days after you last had unprotected sex.
Time of day
You can test at any time of day, but first-morning urine usually has the highest concentration of hCG — useful when testing early or when a previous result was faint. Avoid drinking a lot of fluid just before testing.
If the result is negative
A negative result is less certain than a positive one, especially if you tested early. If your period still hasn’t come, test again in a few days. If you get another negative and still have no period, speak to a GP or doctor.
If the result is positive
A positive result is very likely to be correct. Contact a healthcare professional to confirm the pregnancy and start your care — in the UK, you can refer yourself to a midwife. If you have severe pain or heavy bleeding, seek urgent medical help.
Keeping track
LineCheck can remind you when to test or retest, and keeps each result with its date and photo so you can compare tests over several days. It doesn’t replace your test’s instructions or a confirmation from a professional.
