Miscarriage, miscarriage or habitual abortion in the middle of pregnancy is a very bad thing for everyone. This is because it brings not only physical harm, but the psychological level has a deeper, farther and more terrible impact. The better the embryo grade is the higher the rate of implantation, and the causes of its miscarriage and embryonic abortion can be divided into three aspects: embryonic, maternal and paternal, among which embryonic causes are the most important. Embryonic chromosomal abnormalities and genetic abnormalities account for 60% to 70% of embryonic abortions, which are broken down in detail below. (1) Chromosomal problems If chromosomal abnormalities are present, they can also lead to early miscarriage due to non-development of the embryo. Chromosomal abnormalities include quantitative and structural abnormalities, quantitative abnormalities can be divided into aneuploidy and polyploidy, the most common abnormal karyotype is triploidy, and trisomy 16 accounts for 1/3, which is often lethal. 25-67% of trisomy 21, 4-150% of trisomy 13, and 6-33% of trisomy 18 are bound to miscarriage. Others are haploid, tetraploid due to abnormal oogenesis resulting in embryonic failure. Structural abnormalities include deletions, balanced translocations, inversions, and overlaps. Balanced translocations are the most common chromosomal abnormality. Aging eggs are the number one killer of older women, and chromosomal variants that occur due to aging – appear to be more common in women over 35 years of age. After the age of 40 years, the tendency for this variation is even stronger reaching almost 85% variation. Generally women older than 35 years old have aging eggs and are prone to chromosomal non-separation, leading to chromosomal abnormalities; semen abnormalities, such as large-headed malformed sperm most of which are diploid, form polyploid embryos after fertilization leading to miscarriage. Examination methods: In case of fetal arrest or miscarriage, the chromosomal variation in the embryo in the check out material, but the genetic chromosome examination of both husband and wife are normal, the main suspicion is that the chromosomal variation occurs in the aging egg. In general, eggs with chromosomal variants do not develop into embryos after fertilization, or do not reach the fifth or sixth day. However, some women have biochemical or aborted fetuses, depending on how far the abnormal embryo has traveled. The older male partner may also have a sperm chromosome variation that causes the female partner to miscarry, but the main cause is still the aging of the female egg. (2) Endocrine disorders Embryo implantation and continued development depend on a complex endocrine system coordinated with each other, and any malfunction can lead to miscarriage. The early development of the embryo requires three important hormone levels: estrogen, progesterone, and human chorionic gonadotropin, and if the mother does not have enough endogenous hormones to meet the needs of the embryo, it may cause embryonic arrest and miscarriage. Luteal insufficiency is the most common cause of luteal insufficiency, which can cause delayed endometrial development and short luteal phase, thus affecting the implantation of fertilized eggs or early pregnancy miscarriage. Luteal insufficiency is often accompanied by other glandular abnormalities, such as hyper- or hypothyroidism, diabetes mellitus, androgenism and hyperprolactinemia, all of which are detrimental to the development of the embryo and are closely related to miscarriage. (3) Immunological factors The embryo or fetus in the womb of pregnancy is actually a homozygous transfer, because the fetus is a combination of the genetic material of the parents and the mother cannot be identical. The immune maladjustment between mother and fetus causes maternal rejection of the fetus. Common autoimmune diseases are systemic lupus erythematosus, scleroderma, mixed connective tissue disease, dermatomyositis, etc. The second is the problem of reproductive immunity, if we carry certain antibodies ourselves, it may affect the development of the embryo. (4) Influence of adverse environment Such as toxic chemicals, radiation, high temperature, etc. can also cause chromosomal abnormalities in embryos. Therefore, it is recommended that families planning to get pregnant and those who are already pregnant should not live in newly renovated houses or buy new furniture, new cars and other products for the time being to avoid exposure to undesirable factors that may lead to infertility or miscarriage. Therefore, patients and spouses who have had a miscarriage or spontaneous abortion should be actively screened 4-6 months before the next pregnancy preparation to reduce the risk of another miscarriage.