A biochemical pregnancy is one in which the sperm and egg are transported to the uterine cavity after union and the endometrial implantation in the uterine cavity stops developing before it can be seen by ultrasound, accounting for about 2/3 of early miscarriages. there are many causes of biochemical pregnancy, not only the egg and sperm, but also other aspects, including maternal diseases and environmental factors. Under normal circumstances, the sperm and egg unite in the fallopian tube to form a fertilized egg and then continue to disaggregate and proliferate, running towards the uterine cavity under the ciliary oscillation of the ciliated epithelial cells of the fallopian tube and peristalsis of the fallopian tube, entering the uterine cavity on the fourth day and settling into the endometrium. The fertilized egg usually lays on day 6-7 after fertilization and begins to secrete human chorionic gonadotropin (HCG). After implantation, the embryo divides and proliferates continuously and develops into a blastocyst. In contrast, biochemical pregnancy is mainly a result of embryo implantation going through 3 stages: positioning, attachment and implantation. Problems in any of these stages may lead to failure of implantation or stagnation of cell division and proliferation after implantation, resulting in biochemical pregnancy or miscarriage. Therefore, sperm problems are only one of the factors that can cause a biochemical pregnancy. Some studies have shown that male age and semen quality are associated with the occurrence of biochemical pregnancy. The occurrence of biochemical pregnancy is related to endometrial thickness, maternal hormone levels, egg quality, embryonic chromosomes, maternal age, previous history of biochemical pregnancy or miscarriage, maternal immune factors, male age and semen quality, and sperm problems are only one of the causes. Usually patients with biochemical pregnancy are not aware of it, thinking it is a normal menstrual flow, and the cause of biochemical pregnancy is not easily identified. Biochemical pregnancy does not affect the next pregnancy. Only pregnant women with recurrent biochemical pregnancy need to be examined for the cause of biochemical pregnancy and need to be treated.