Generally speaking, the earliest way to confirm pregnancy is through blood tests for human chorionic gonadotropin ten days after intercourse, urine tests take about half a month at the earliest, and ultrasound tests for early pregnancy are even later, usually after the menstrual period has been delayed for one week. If the couple has intercourse during ovulation and the sperm and egg combine successfully, it takes about 24 hours for the sperm to break through the zona pellucida of the oocyte and combine with the egg to form a fertilized egg. It takes about 24 hours for the fertilized egg to form after it breaks through the zona pellucida of the oocyte and combines with the egg to form a fertilized egg. At this time, the level of blood or urine is very low, the test results are prone to error, it is best to test after two or three days, you can first test the urine pregnancy test, inaccurate when the blood HCG test. In short, for regular menstrual cycles of women, generally 10 days after intercourse blood HCG test can confirm whether the pregnancy; and irregular menstrual cycles of women, generally six weeks after menopause can be detected.