Thin endometrium, also known as thin endometrium, is mainly caused by endometrial damage after uterine operations, followed by endometrial adhesion damage due to infectious diseases of the uterine cavity, and in a few patients, by unexplained thin endometrium. Endometrial thinning due to recurrent embryo transfer failure Endometrial thinning is an important factor causing fertility problems such as infertility, recurrent miscarriage, and recurrent embryo transfer failure, therefore, the treatment of thin endometrium is a key and difficult area in the field of reproduction. All patients in this category should first undergo hysteroscopy, especially those with endometrial discontinuity suggested by 4-dimensional ultrasonography, which basically has varying degrees of uterine adhesions. There are two types of hysteroscopy lenses, one is the lens of simple hysteroscopy, the lens is thin, so there is no need to dilate the uterus, most of them do not have anesthesia, the operation is very fast and can be finished basically within 10 minutes, it is only a hysteroscopy, if problems are found they cannot be dealt with at the same time, at most the endometrium is scraped or lightly invasive at the same time, this kind of operation is suitable for patients with repeated embryo transfer failure but the ultrasound suggests that the endometrium does not see obvious This procedure is suitable for patients with repeated failed embryo transfer but no obvious abnormalities in the endometrium as indicated by ultrasound, so that abnormalities and inflammatory diseases in the uterine cavity can be excluded through hysteroscopy, and endometrial scraping or light invasion can be performed to improve the endometrial tolerance and increase the conception rate. Intravenous anesthesia is used. This type of surgery can be performed at the same time once the uterine cavity problem is detected. For not very serious cervical adhesions, one surgery can basically solve the problem, while more serious patients may need 2-3 surgeries. At present, most of the surgeries for uterine adhesions are performed with cold knife treatment, and the adhesions are gradually trimmed by micro scissors. Serious adhesions cause serious damage to the scissors and are time-consuming and laborious, so some hospitals also take electric knife treatment, which significantly shortens the operation time, but electric knife surgery increases the risk of endometrial damage. 2, drugs to promote endometrial reproduction Drugs to promote endometrial reproduction include estrogen, drugs to improve endometrial blood supply and growth hormone, etc. Clinically used estrogens are natural estrogens, including Glaxo, Fentanyl, Esto, etc. Glaxo is used orally, Fentanyl can be used orally or vaginally, Esto is a gel used transdermally. Drugs that improve the blood supply to the endometrium include aspirin, low molecular heparin, and Viagra. Aspirin and low molecular heparin mainly act as anti-platelet anticoagulation, and Viagra has the effect of vasodilatation to improve microcirculation. In addition, growth hormone can promote cell proliferation, also has the role of long endothelium. 3.Local uterine medication Uterine medication is a relatively new treatment method for thin endometrium, mainly used in patients with repeated embryo transfer failure caused by thin endometrium, and it is reported in the literature that it can significantly improve the embryo implantation rate. The drugs used are G-CSF and GM-CSF, and their mechanism of action may be related to local immunomodulation of the uterine cavity and promotion of endometrial basal cell proliferation only. For patients with repeated embryo transfer failure in thin endometrium, this type of treatment can be carried out in our hospital. 4.Other treatments There are reports in the literature that intrauterine stem cell transplantation can be performed to promote endometrial growth in patients with severe endometrial damage. The principle may be related to the proliferative and immune effects of stem cells, but it is still in the scientific research stage.