Endometrial thinness of 4mm, if it occurs just after menstruation, in the follicular phase or for postmenopausal women, is usually normal and no special treatment is necessary. If it is not one of the above, it is a severe thin endometrium, which requires treatment at this time, and the main treatment methods include the following: 1. Hormone supplementation: oral, intramuscular injection or local application of estrogen. Oral high-dose estradiol valerate tablets can significantly increase the thickness of the endometrium in the mid-luteal phase, with an average increase of about 4 mm. other hormones that improve the endometrium include GnRHa, tamoxifen and growth hormone, all of which can increase the thickness of the endometrium and obtain a more satisfactory pregnancy rate and embryo implantation rate; 2. improve endometrial blood flow: according to the hemodynamic characteristics of thin endometrium, some scholars propose regular The application of low-dose aspirin, sildenafil and hexoketone cocaine can promote endometrial vascular regeneration and improve endometrial local blood perfusion; 3, stimulation of endometrial cells: the use of platelet-rich plasma can activate endometrial cell migration, proliferation and differentiation, improve the endometrial microenvironment, promote endometrial growth and embryonic implantation, and increase the pregnancy rate; 4, bone marrow stem cell repair: currently used for stem cells for the treatment of thin endometrium mainly include bone marrow mesenchymal stem cells, endometrial stem cells, human embryonic stem cells, adipose mesenchymal stem cells, transmural blood stem cells, peripheral blood stem cells and human umbilical cord Huatong gum mesenchymal stem cells. In addition, a combination of Chinese and Western medicine can be used to improve the endometrial condition by taking deer antler, which has the effect of tonifying the kidney and invigorating blood and warming the uterus and nourishing the membranes, and combining with estrogen, which promotes the growth of the endometrium.