Fetal arrest is usually most likely to occur before 12 weeks of pregnancy, especially around 8-9 weeks of pregnancy. There are many causes of fetal arrest, the most common is chromosomal abnormality of the embryo, which is often related to the chromosomes of both husband and wife, and it may also be related to the infection of various viruses in the early stage of pregnancy, such as HPV virus, cytomegalovirus, herpesvirus, mycoplasma and chlamydia infections, and so on. In addition, abnormal thyroid function, autoimmune diseases, environmental pollution, and poor living habits may also lead to fetal arrest. If one fetal arrest occurs, you need to check the eugenics four, thyroid function, leukorrhea routine and other routine checkups before the next pregnancy preparation. If there are more than two consecutive abortions, you need to check the chromosomes and immune system of both spouses. In addition, the woman needs to take oral folic acid to prevent fetal neural tube defects in the first three months of pregnancy.