Clinically, many patients with spontaneous abortion or recurrent miscarriage will come across a medical term “Fetal Arrest”, so what exactly is meant by “Fetal Arrest”? What are the causes of “fetal arrest”? What kind of tests are necessary for a “fetal arrest”? Will it happen again in the next pregnancy? Fetal arrest is a condition in which the embryo dies at a certain stage of development and stops developing. It includes biochemical pregnancies, empty sacs, babies with buds but no fetal heartbeat, and babies with a fetal heartbeat that stops developing. It is a major culprit in “spontaneous abortion”, “recurrent abortion” and “habitual abortion”. 1, so here we review what is called “spontaneous abortion”, “recurrent miscarriage” and “habitual abortion”? Spontaneous abortion: the failure of the pregnancy process, embryonic death and embryo and appendage discharge, embryo and appendage <1000g, gestational period <28 weeks. 80% of spontaneous abortion occurs before 12 weeks of gestation, clinically referred to as early miscarriage; Repeated miscarriage (RSA): most of the experts and scholars in China believe that the RSA is the same sex partner with the same two consecutive times or two or more times in the gestation of the 20 weeks of fetal loss; habitual miscarriage; habitual miscarriage; recurrent miscarriage. Fetal loss; habitual abortion: 3 or more consecutive occurrences of spontaneous abortion, the incidence of spontaneous abortion clinically 15% to 25%, the occurrence of 2 or more than 2 abortions of patients accounted for about 5% of women in their childbearing years, while 3 or more than 3 times accounted for about 1%. 2.What are the causes of fetal arrest? The etiology of fetal arrest is very complex, chromosomal factors, anatomical factors, immune factors, endocrine factors, infectious factors, environmental factors, maternal systemic diseases, pre-thrombotic state and so on may have an impact, sometimes it is the result of a variety of factors work together. However, spontaneous abortion caused by different causes usually occurs in different periods of pregnancy. 3.What should be done in the event of fetal arrest and recurrent or habitual abortion? First of all, the embryo or fetus chromosome examination. Embryonic or fetal chromosomal abnormalities are the most common cause of early spontaneous abortion, accounting for about 50%-60%, of which chromosomal triploidy abnormalities account for 10%-20% of all chromosomal abnormalities. It can be seen that chromosomal testing of aborted tissue is very necessary. In addition, early pregnancy Down screening, chorionic villus puncture, mid-early Down screening, non-invasive DNA, amniocentesis, umbilical cord blood puncture, fetal histochemistry is also a way to rule out abnormal development of the embryo or fetus. Secondly, both husband and wife should be examined together to clarify the cause and target treatment. Items to be examined together: Karyotype analysis of both husband and wife (About 2%~5% of the cases are caused by chromosomal abnormality of parents, and the most common one is chromosomal ectopia or inversion. If the parents are known to have genetic factors, the chance of having an empty gestational sac may be higher). Blood type (to rule out blood group incompatibility, including ABO blood group incompatibility and RH blood group incompatibility). 4.Fetal arrest female checkup items Anatomical factors: three-dimensional ultrasound, hysteroscopy, laparoscopy. Define whether there is any abnormality in the development of uterus, whether there is uterine fibroid or adenomyosis, and whether there is any pelvic lesion. For those who are suspected of having abnormal uterine anatomy, further examination through hysteroscopy, laparoscopy or three-dimensional ultrasound is needed to make a clear diagnosis; Infectious factors: TORCH, leukorrhea, mycoplasma, chlamydia, mycobacteria, trichomoniasis, hepatitis B virus, AIDS, syphilis, etc.; Endocrine factors: reproductive endocrinology, thyroid function, blood glucose (OGTT + IRI for 3 times). Diagnosis of hyperprolactinemia, ovulation disorder, hyperthyroidism, hypothyroidism, hyperandrogenemia, insulin resistance, diabetes mellitus, luteal insufficiency, polycystic ovary syndrome (PCOS), etc.; Immunological factors: infertility antibodies, closed antibodies, thyroid antibodies (TGAb TPOAb). All patients with early RSA and those who have had 1 or more unexplained fetal losses after 10 weeks of gestation should be screened for antiphospholipid antibodies, and unexplained RSA should be considered to be related to homozygous immune disorders; Pre-thrombotic states: lipids, blood coagulation, platelet coagulation rate, D-2 polymorphisms, autoantibodies (antinuclear, anti-DNA, anti-beta-glycoprotein 1, lupus anticoagulant, homocysteine), prothrombotic triple (TGAb, TPOAb). ), easy to embolism three (protein c, protein s, antithrombin); pregnancy hypercoagulable state of the placenta parts of the blood flow state changes, easy to form local micro-thrombosis or even caused by placental infarction, so that the blood supply of the placental tissues decreased, the embryo or fetus ischemia and hypoxia, ultimately leading to the development of the embryo or fetus and miscarriage; other factors may affect: trace elements, folic acid utilization. 5. Male tests for fetal arrest Semen causes: Semen analysis Increased leukocytes in semen (>1×106/ml), oligospermia (<20×106/ml), polyspermia (>250×106/ml), dyszoospermia (>85% of abnormal spermatozoa), as well as concentration of sperm cell nuclei and chromatin can lead to fetal arrest and recurrent miscarriage; Sperm DNA fragmentation rate Spermatozoa Nuclear DNA breakage or fragmentation has an adverse effect on pregnancy. Sperm DNA fragmentation rate of >30% can lead to fetal arrest and recurrent miscarriage; Anti-sperm membrane antibodies (MAR) Anti-sperm antibodies in the male partner due to reproductive tract infection, injury, surgery, etc., not only affect spermatogenesis, sperm motility, and sperm passage through cervical mucus and zona pellucida, but also impede the implantation of a fertilized egg and the development of the embryo, leading to miscarriage; Infections Mycoplasma, Chlamydia, TORCH, Hepatitis B virus, and other infectious agents. Infectious factors Mycoplasma, Chlamydia, TORCH, Hepatitis B virus, AIDS, syphilis and so on. 6, in addition to the adverse factors causing fetal arrest also include: adverse environmental factors: excessive exposure to harmful chemicals, excessive exposure to radiation; adverse psychological factors: mental tension, negative emotional depression and fear, sadness, etc., a variety of adverse psychological stimuli can affect. Neuroendocrine system, making the body’s internal environment change, thus affecting the normal development of the embryo. Excessive physical labor, smoking, alcoholism, drinking too much coffee, drug abuse and drug addiction and other bad habits, as well as sexual life during pregnancy.