Invisible miscarriage refers to biochemical pregnancy, which is an early miscarriage within 5 weeks of menopause and belongs to spontaneous abortion. Invisible miscarriage does not have obvious symptoms, most of the manifestations of menstruation delayed for a few days, menstrual flow than the previous slightly increased, and will not attract attention, at this time to do urine test paper will be positive or check the blood HCG value is elevated, but ultrasound can not be seen in the gestational sac, suggesting that the fertilization of the egg to bed failure. Invisible miscarriage represents pregnancy and miscarriage under unknown circumstances. The beginning of pregnancy is the combination of sperm and egg, but in some women with low progesterone, thin uterine lining or chromosomal abnormality, the fertilized egg stops developing soon after its formation, unknowingly resulting in miscarriage. In order to detect and prevent invisible miscarriage, you must pay attention to your menstrual situation, once the menstrual period is delayed or after 8 days of coitus, you can be tested by a pregnancy test, blood test, and if there are repeated invisible miscarriages, you need to do the relevant laboratory tests to find out the cause of the disease.