If you have a regular menstrual cycle in general, the test paper can usually detect the pregnancy in about two weeks. However, if a woman’s menstrual cycle is irregular, the time to detect a positive test will be delayed. Pregnancy self-tests using pregnancy test strips work by detecting the value of HCG, or human chorionic gonadotropin, in the urine. This hormone is produced by placental syncytiotrophoblast cells, and HCG in the blood can be measured as early as 6 to 8 days after conception. HCG is secreted in the blood and then in the urine as it travels through the circulatory system, but due to its small amount, it is not easy to detect in the urine at first, and it becomes increasingly obvious only after the second week of pregnancy. Therefore, if you have regular menstrual periods, test strips can usually detect pregnancy in about two weeks, and some women can detect it in 10 days after pregnancy, but there are individual differences.