Miscarriage refers to the interruption of pregnancy before the 28th week of pregnancy. The main causes of miscarriage are abnormalities of the pregnant egg and embryo, followed by maternal pathologies (endocrine dysfunction, uterine malformations and maternal systemic diseases) and external factors (abdominal surgery or trauma). In early miscarriage, abnormal embryonic development accounts for 80% of cases. Abnormal embryo development can be caused by defects in the egg or sperm or both, and the vast majority of them end up in miscarriage or stillbirth due to developmental disorders. Traditionally, people believe that habitual miscarriage is caused by the female partner, such as endometrial dysplasia, cervical endocervical insufficiency, and blood type incompatibility between mother and child. However, this understanding is not comprehensive. Modern medicine believes that habitual miscarriage, especially the habitual miscarriage of every child, is often related to the man, which mainly includes the following factors: Chromosomal factors Sperm with chromosomal abnormalities are usually difficult to fertilize the egg because of their poor quality, and if they are lucky enough to fertilize the egg, the result is bound to end in miscarriage. Immunological factors When a woman becomes pregnant, the embryo is also a foreign body to the mother and is bound to be rejected by her immune system. However, the presence of blocking antibodies in the conceived mother protects the fetus from rejection. When the cell typing of the couple is close, the antigens are not sufficient and the mother lacks the necessary blocking antibodies, making miscarriage more likely. Sperm Factors Poor quality sperm is difficult to conceive, but does not exclude the possibility of conceiving the woman, and habitual abortion usually occurs if the woman is occasionally conceived. In addition to the above factors, there are other factors that can cause habitual abortion. For example, sexual intercourse during pregnancy can produce mechanical stimulation to the fertile uterus, and the prostaglandins in the semen can make the uterus contract; some harmful factors in the work and living environment of the male partner, which damage the germ cells and induce chromosomal aberrations in the sperm, all of which may lead to habitual abortion. Therefore, both men and women have a variety of factors that cause habitual abortion. If a habitual miscarriage occurs, you should go to a maternity hospital in time to have an examination to find out the cause and treat it properly.