Longitudinal diaphragm is a manifestation of incomplete cavitation of the uterus during congenital development, manifested by a connective tissue-based ridge at the base of the uterus that protrudes into the uterine cavity, with deep double uterine horns and a small volume of the uterine cavity, which can be seen horizontally by vaginal ultrasound. A large mediastinum can lead to infertility, just like a “meat ring” placed in the uterine cavity, which is equivalent to a birth control ring; a small mediastinum can lead to habitual abortion, probably because a fertilized egg is laid on the mediastinum, which leads to fetal abortion due to poor blood supply. According to statistics, nearly 15% to 25% of recurrent miscarriages are due to malformed uterus, of which mediastinum accounts for the majority. The incidence of longitudinal uterus is high in women with repeated pregnancy failure, especially early pregnancy failure. The incidence of miscarriage in women with a longitudinal uterus has been reported to be 25.5% in early pregnancy (12 weeks of gestation) and 6.2% in late pregnancy. This implies that longitudinal uterus affects the early implantation and late development of embryos, which leads to the occurrence of early or late miscarriage. 2. Infertility The incidence of infertility in longitudinal uterus is 17% to 35%, and the pregnancy rate is 48% after undergoing orthopedic surgery for longitudinal uterus. Some scholars believe that longitudinal uterus is not a factor causing infertility, but the incidence of unexplained infertility is significantly higher in patients with secondary infertility up to 40%. Therefore, it cannot be ruled out that longitudinal uterus is one of the factors affecting conception in such patients. 3, obstetric abnormalities due to the influence of mediastinum, the uterine cavity is deformed, resulting in an increased incidence of late pregnancy complications, such as preterm delivery rate of ll% to 28%. The preterm birth rate can be reduced to 6% to 9% after orthopedic surgery. Uterine malformation can also lead to obstetric complications such as abnormal fetal position, uterine contractile dysfunction, and retained placenta. Treatment The best treatment is hysteroscopic incision of the mediastinum, enlargement of the uterine cavity, done more safely and accurately under laparoscopic supervision, and postoperative placement of a biological anti-adhesive membrane. It is not necessary to perform a single operation for a large mediastinum, but it is possible to perform several operations, and it is important not to “overdo it”, as this can cause excessive scarring of the uterine fundus, which can affect conception. Longitudinal uterus is the result of congenital development and obstruction in the fusion of the two paramedian tubes. It should belong to the category of incomplete congenital separation of the uterine cavity. It is usually asymptomatic and does not affect pregnancy, but can lead to fetal abortion and recurrent spontaneous miscarriage. The traditional treatment is hysteroscopic resection of the mediastinum, postoperative release of the ring, and prevention of adhesions with an artificial cycle.