It helps to understand the causes of habitual abortion, such as relaxation of the endocervix, old lacerations and defects of the cervical canal, uterine malformations, and uterine adhesions. Infertility patients with abnormalities under hysteroscopy account for 19%-62%; if hysteroscopy is combined with laparoscopy, more comprehensive understanding of the causes of infertility can be obtained and corresponding treatment can be given. 1.Insertion of tubes under direct hysteroscopy and injection of fluid under pressure to diagnose and unblock the fallopian tubes Tubal obstruction is an important cause of female infertility, accounting for about 30% to 50% of female infertility, and with the increasing incidence of sexually transmitted diseases and the increase in the number of hysteroscopic operations, the trend has been increasing year by year. The mature application of hysteroscopic intubation and pressure injection has enabled some patients with tubal infertility to be effectively treated and successfully obtain intrauterine pregnancy, with a success rate of more than 80%. Under direct vision, hysteroscopy can not only classify the degree of adhesions, but also separate the adhesions without hurting the normal mucosa, which is safer, more thorough and more effective than blind separation. The rate of menstruation returning to normal is 76.5% and the rate of pregnancy is 86.2%. 3.Removal of residual pregnancy and birth control device The residual of small amount of pregnancy during multiple abortions or the residual bone fragment after scraping of larger pregnancy can lead to secondary infertility; there are also residual uterine cavity with broken birth control device, which affects conception. It is easy to find and remove them under direct view of hysteroscope. 4.Removal of longitudinal uterus Longitudinal uterine septum can be a uterine malformation, which is prone to miscarriage, embryonic abortion, premature birth and fetal malposition. After the diagnosis is confirmed under hysteroscopy, the longitudinal septum can be removed under the microscope. 5. Diagnostic examination before IVF embryo transfer Hysteroscopy should be performed in every case where pregnancy cannot be achieved after transfer of high quality embryos. It is also recommended to routinely do hysteroscopy beforehand to detect intracavitary lesions, such as uterine adhesions, small myomas and polyps.