In early pregnancy, especially when the fertilized egg is laid, many pregnant women will experience a small amount of bleeding due to a transient drop in hormone levels, and the bleeding will be delayed in the vagina and will appear as brown discharge. In pathological cases, brown discharge, slow development of embryo, no doubling of HCG level in the body, empty sac in the second month of pregnancy, no fetal bud and fetal heart on schedule, embryonic abortion needs to be performed in time.