Usually, the pregnancy can be detected 3-4 days after the fertilized egg has been implanted in the uterine cavity. The chorionic gonadotropin level will start to increase after the fertilized egg has been laid, and a blood test will be able to detect an increased chance of pregnancy in women, but it will not be able to confirm whether the pregnancy is normal or not, and there is a possibility that an ectopic, biochemical or intrauterine pregnancy has occurred. To confirm a normal intrauterine pregnancy, it is best to have a gynecologic ultrasound about 10 days after the postponement of the menstrual period. A normal intrauterine pregnancy is diagnosed if there is full gestational sac growth and the presence of a fetal bud in the uterine cavity, and if the chorionic gonadotropin level is significantly increased. In rare cases, the fertilized egg is slow to grow and develop in the uterine cavity and may also be detected late after implantation, which can be delayed until about 10 days after implantation. In addition, after having sex during ovulation, women should stay relaxed and avoid smoking, drinking, staying up late, drugs and other unfavorable external stimuli.