It is normal for a woman to have her period a week early or late, but if it is longer than that you should consider if there is a health problem or if you are pregnant. Within 1-2 days after intercourse, the male partner’s sperm can reach the female partner’s fallopian tubes, where it meets the egg from the female partner’s ovary and unites to form a fertilized egg. In the next 6-7 days, the fertilized egg is pushed by the cilia in the fallopian tube to reach the uterus and, if the conditions are right, then it can implant in the endometrium. The sign that a woman is pregnant is when the fertilized egg is in the womb, so it takes at least 6-7 days to detect pregnancy. In addition, if you want to determine whether you are pregnant, you can also observe any early pregnancy reactions, such as vomiting and nausea, dizziness and weakness, back pain, etc. Finally, you can determine whether you are pregnant based on ultrasound, blood test, urine test and early pregnancy test paper. However, delayed menstruation is not always a sign of pregnancy. Neuroendocrine dysfunction, organic lesions or drug effects, as well as excessive mental tension, environmental changes, poor nutrition and other factors may lead to delayed menstruation or no menstruation. It is advisable to go to a regular hospital for detailed examination to make a clear diagnosis.