The endometrium is the soil for embryo implantation and development and plays an important role in the pregnancy process. Clinical monitoring of endometrium morphology and thickness is used to guide treatment and embryo transfer. Many people ask during ovulation monitoring in the clinic: Why is my lining so thin? Can drinking soy milk and eating black beans make the lining grow? Under normal circumstances, the endometrium thickens with the development of follicles and the rise of estrogen, but in some people, the endometrium is always very thin and cannot be thickened with follicular development or even with topical medication, which is called refractory endometrium. In 1997, Remohà et al. and 2011, Cai et al. found that endometrial thicknesses ranging from 5mm to greater than 15mm had a similar chance of success, and that successful pregnancies and deliveries were reported even for endometrium thicknesses less than 5mm. Today we will talk about the causes of thin endometrium and the current stage of treatment. The most common cause of thin endometrium is surgical endometrial adhesions. The damage to the endometrium leads to the formation of fibrous connections between the endometrium during the repair process, and more than 90% of endometrial adhesions are the result of post-abortion curettage, manifesting as low menstrual flow and failure of embryo implantation, as well as recurrent miscarriage, preterm delivery, and placental adhesions. Similarly, various intrauterine operations including electrosurgery and hysteroplasty such as diastasis and bicornuate hysteroplasty may cause uterine adhesions and lead to thinning of the endometrium. In patients with recurrent miscarriage, it has been found that chronic endometrial inflammation may be the culprit, and in these patients, hysteroscopy is valuable for diagnosis, and patients treated with regular, adequate and full course of antibiotics have a significantly better prognosis and a significantly higher rate of embryo implantation compared to untreated patients, and combined with acupuncture and other TCM treatments also have good efficacy. In some malignant tumors, radiotherapy can lead to smaller uterine cavity, thinner endometrium, reduction of uterine length and impaired endometrial blood flow. The endometrial damage caused by radiotherapy is dose- and age-related, and the younger the age, the more severe the damage and the less likely the recovery. The female reproductive tract develops in the early embryonic stage from the malleolus, which develops into the fallopian tubes, uterus and upper vagina, usually in the 20th week of embryonic development. Abnormal expression of some genes, such as the homologous frame gene (HOX), can also cause developmental malformations. Treatment The following treatments are currently recognized and largely proven to improve thin endometrium, both nationally and internationally. In conclusion, the diagnosis and treatment of thin endometrium, especially refractory endometrium, has always been a difficult problem, and the treatments described above are not effective for everyone, and dietary therapy has not been proven to have significant effects.