Fetal biochemistry mostly refers to biochemical pregnancies that occur in the early stages. A biochemical pregnancy is a pregnancy in which a sperm and an egg unite to form a fertilized egg, but for some reason the fertilized egg does not settle and develop in the uterine lining and is expelled from the uterus with the menstruation, resulting in a miscarriage. After a biochemical pregnancy, the blood test for human chorionic gonadotropin (HCG) level will also increase, indicating pregnancy, but the doubling of HCG is not obvious and then gradually decreases, and there is no gestational sac in the uterine cavity on ultrasound examination of the uterine adnexa. Biochemical pregnancy may be caused by a variety of factors, such as: chromosomal abnormalities on both sides, hormone deficiency in the female body, etc. If an occasional biochemical pregnancy occurs once, it usually does not need to be treated. If it happens more than twice, you need to consult a doctor to find out the cause and treat the cause under the doctor’s guidance.