If conception is successful after ovulation, HCG can usually be detected in the blood or urine on the 8th-10th day after intercourse to confirm pregnancy. If conception occurs in time after ovulation, HCG is usually produced by the placental trophoblast cells about 1 week after ovulation, with a significant increase in HCG levels around the 9th-13th day after ovulation. If the pregnancy is intrauterine and the fetus grows and develops at a normal rate, HCG in the blood will increase at a rate of 66% per day and can increase exponentially every other day, generally reaching a peak at 8-10 weeks of gestation, after which the HCG value in the blood will drop rapidly. Therefore, testing for HCG in blood or urine is relatively fast and reliable for the diagnosis of early pregnancy. Therefore, once early pregnancy is confirmed, it is necessary to go to the obstetrics department of the hospital for further ultrasound at around 42 days of menopause to determine if the pregnancy is intrauterine and to understand the development of the embryo.