Timing a pregnancy test for the most reliable result
Home pregnancy tests detect human chorionic gonadotropin (hCG), a hormone produced after a fertilized egg implants in the uterus — typically around 6 to 10 days after ovulation. hCG levels start low and roughly double every two to three days in early pregnancy, which is why timing matters so much for getting a reliable result.
Why earlier isn't always better
Testing too early — before hCG has had time to rise to a detectable level — is the most common cause of a false negative in someone who is actually pregnant. Even "early result" tests advertised as highly sensitive can miss a very early pregnancy if hCG hasn't risen enough yet.
The most reliable single day
Testing on the day of a missed period — when hCG has had the most time to accumulate since implantation — gives the most reliable result for a single test. If your cycle is irregular, this date is naturally less certain, which is part of why a negative result with a still-missing period is usually worth a repeat test a few days later.
Getting the most accurate reading
First-morning urine is generally the most concentrated, giving hCG the best chance of reaching a detectable threshold if testing early. Following the specific test's instructions exactly — including how long to wait before reading the result — also matters more than people often expect.