Early pregnancy test usually detects pregnancy 35 days after menopause or about 20 days after intercourse, but the test is subject to interference from other hormones and may be inaccurate. The waiting time for fertilization after intercourse is usually 1-3 days, and it takes 3-4 days for the fertilized egg to move from the fallopian tube to the uterus, 2-3 days for implantation, and about 7 days for hCG to be produced. hCG appears in the urine a little later, and the concentration of hGC is low at the beginning, so the test may not be positive at this time. It is recommended to use morning urine when testing with early pregnancy test strips because the concentration of hCG in the urine is relatively high after a night of concentration, which can make the test more accurate. In addition, if there is a recent history of pregnancy, hCG may remain positive for about 2 months after termination of pregnancy, whether it is a normal birth, miscarriage or ectopic pregnancy. The early pregnancy test is only a preliminary screening test and is subject to certain deviations. If the menstrual cycle is more irregular and the test is negative, it is recommended to retest every 1-2 days. In addition, if you have early pregnancy symptoms such as nausea, vomiting, weakness and drowsiness, but the test is still negative after several consecutive early pregnancy tests, it is recommended to go to the gynecology department of the hospital to have blood test for hCG in time for higher accuracy.