Pregnancy tests detect the hormone human chorionic gonadotropin (hCG), which begins to be produced after a fertilized egg implants in the uterus. The timing for when a pregnancy test can detect pregnancy depends on the sensitivity of the test and the level of hCG in the body.
- Earliest detection: Some of the most sensitive pregnancy tests can detect hCG as early as 6 to 8 days after ovulation or conception, which is roughly 6 days before a missed period
. Trace levels of hCG start appearing around 6 days after fertilization, but levels may be too low for many tests to detect reliably this early
- Optimal timing: For more accurate results, it is recommended to take a pregnancy test on the day of your expected period or after a missed period, typically about 14 days after conception. Testing at this time reduces the chance of false negatives because hCG levels have had time to build up sufficiently
- Accuracy considerations: Testing too early can result in a negative test even if you are pregnant, due to insufficient hCG levels. Using the first morning urine, which contains the most concentrated hCG, and waiting at least 3 hours after last urination can improve test accuracy
In summary, while some tests can detect pregnancy about 6-8 days after ovulation, the best time to take a pregnancy test for reliable results is on or after the day your period is due, about 14 days post-conception
