The uterus is formed around the 8th to 16th week of embryonic life and undergoes a complex process of development of the paramesonephric ducts, fusion, cavitation, and mediastinal resorption, and obstruction of development at any stage can lead to uterine malformations. Normal uterus is inverted pear shape with slightly flattened front and back, about 7-8cm in length, 4-5cm in width and 2-3cm in thickness, and the uterine cavity is inverted triangle with wide top and narrow bottom, with a capacity of about 5 ml. In addition to abnormal uterine morphology, malformed uterus is often characterized by endometrial dysplasia and abnormal distribution of blood vessels, which affects embryo implantation and results in infertility; and the uterus and cervical muscular layer are weak, which is easy to be combined with cervical insufficiency, resulting in miscarriage, premature rupture of membranes and preterm labor. The uterus and cervix are weak, which can easily be combined with cervical insufficiency, leading to miscarriage, premature rupture of membranes, preterm labor, etc. Due to the complexity of uterine formation and development, uterine malformations are divided into a variety of its impact on pregnancy can not be generalized, different categories of uterine malformations on pregnancy and pregnancy outcome can cause different degrees of impact, the treatment measures are not the same. Congenital absence of uterus or uterine hypoplasia: these patients usually lack a functional uterine lining and cannot get pregnant. 1. Bowed uterus (saddle uterus), double uterus, bicornuate uterus: Bowed uterus and double uterus with relatively intact uterine cavity form usually do not affect pregnancy. For bicornuate uterus if the embryo is planted in the uterine horn, it is easy to cause miscarriage or uterine rupture. 2, mediastinum uterus: the most common type of uterine malformation, the uterus mediastinum in addition to affecting the shape of the uterine cavity, the structure of the endometrium is different from the normal endometrial tissue, thus affecting the embryo implantation. And it is easy to lead to repeated miscarriage, preterm labor, premature rupture of membranes and so on. Unicornuate uterus: Unicornuate uterus has abnormal distribution of nerves and blood vessels, insufficient blood supply to the endometrium, endometrial dysplasia, which may affect embryo implantation; myometrial dysplasia, restricted cavity morphology, and increased post-pregnancy complications as compared with normal uterus, which may easily lead to restricted intrauterine growth of the fetus, preterm labor, lack of uterine contraction in labor and uterine rupture. 4, stumpy uterus: unicornuate uterus is often combined with stumpy uterus, stumpy uterus, if the endometrium is functional, but the uterine cavity and unicornuate uterus are not connected, the menstrual blood can not be discharged vaginally after the endometrium is peeled off, and retrograde menstrual blood flow can occur, resulting in endometriosis, which affects the pregnancy. Uterine malformation will affect pregnancy to a certain extent, but it is not an indication for the application of assisted reproduction technology, most of them can have a natural pregnancy, and patients with uterine malformation combined with infertility can be treated with assisted reproduction technology for pregnancy. Before assisted conception, ultrasound and hysteroscopy are needed to evaluate the size of the uterine cavity and consider whether hysteroplasty is necessary according to the condition.