It has also been reported that chromosome 9 is a polymorphism only if the inversion occurs in the hypoconjugate region. If the inversion band goes beyond the hypoconjugate region, the chromosomes will be pairwise exchanged during meiosis and theoretically four types of gametes will be formed, one of which is a normal chromosome, another is a phenotypically normal carrier of the inversion, and the remaining two are chromosomes with partial duplications or deletions, i.e., unbalanced gametes. The magnitude of their genetic effects depends mainly on the length of the duplicated and deletion fragments and the lethal effects of the contained genes. That is, it is related to the survival and normal development of the zygotic embryo. Usually, the shorter the inversions, the longer the duplicated and missing segments, the lower the possibility of normal development of gametes and congeners, and the higher the rate of clinical manifestations of infertility after marriage, prolonged menstruation, early miscarriage, stillbirth and stillbirth, and the lower the possibility of delivering a malformed fetus; if the inversions are longer, the shorter the duplicated and missing segments, the higher the possibility of normal development of gametes and congeners, and the higher the risk of delivering a congenitally malformed fetus. The higher the risk of delivering a fetus with congenital malformations. The size of the duplicated and missing segments and the lethal effect of the genes they contain can lead to impaired formation of half of the gametes or the formation of half of the malformed, non-functional gametes, which can lead to infertility for many years after marriage. It is worth mentioning that more clinical cases of chromosome 9 inversions with spontaneous abortion and malformed children have been reported in recent years, which also suggests that chromosome 9 inversions are a category of pathological inversions that occur more commonly by people; whether abortion or malformed children occur has individual variability and is related to uncertainties such as the size of the inverted fragment, stimulation by environmental factors, recombination and exchange occurring during sperm meiosis, but should be However, it should be taken seriously. Consultation on the genetic effects of inter-arm inversions of chromosome 9 1. The incidence of inter-arm inversions of chromosome 9 is the highest, with a reported incidence of 1.0% in China. 2. Previously, scholars believed that because the genetic material of the inverted chromosome was not obviously lost and the carrier’s phenotype was normal, it was called polymorphism, and the carrier could not show phenotypic effects because the genetic material was not obviously increased or decreased. In recent years, studies have shown that RLX is not only related to pregnancy, but also plays an important role in fertility regulation. If inter-arm inversion of chromosome 9 occurs, especially in the distal part of q12, the role of RLX will be weakened due to the positional effect, which may be one of the causes of infertility. 4. Obstructive azoospermia is closely related to genetic factors, and it is inconclusive whether it is related to chromosome 9 inversion. 5. If you are pregnant, prenatal diagnosis (amniocentesis combined with ultrasound imaging) is recommended after the fourth month of pregnancy. 6.It is recommended to do some corresponding preventive measures at least in the first trimester of pregnancy: such as quit smoking and drinking, ban hot baths, reduce exposure to radioactive contamination, etc., but the effectiveness of the above prevention is not yet determined. 7.Follow up.