Generally, a pregnancy test can be used to detect a woman’s pregnancy at around 32 days. For women who have regular periods (i.e., once every 28 to 30 days), a pregnancy test can be used to detect pregnancy at around 32 days of pregnancy. However, if a woman has an irregular period, which may be delayed for more than 40 days or even more than two months, she cannot test around 32 days of pregnancy. Since pregnancy starts from the first day of the last menstrual period and extrapolates back to 32 days, it is possible that a woman with a delayed period has just ovulated and cannot be detected with a pregnancy test. In this case, it is necessary to test the pregnancy according to the date of sexual intercourse, which can be done with a pregnancy test about 14 days after intercourse. In addition, it should be noted that after a woman has detected pregnancy with a pregnancy test, she needs to go to the hospital for a blood HCG test and ultrasound to clarify the exact location and time of pregnancy.