In vitro endometrial growth may be caused by lack of estrogen, mechanical damage to the endometrium and other reasons, which need to be specifically analyzed. 1. Lack of estrogen: women’s endometrium is regulated by estrogen, and low levels of estrogen in the body will lead to endocrine disorders, and these will change the cycle of the endometrium, resulting in the endometrium not growing up. When the ovarian function declines, the level of estrogen secretion in the body will gradually decrease, so the endometrium can not grow up. 2. Mechanical damage to the lining of the uterus: repeated abortions cause mechanical damage to the lining of the uterus, the lining of the uterus grows more slowly, or even can not grow. If a woman has a situation where the endometrium does not grow, it is recommended to go to the hospital for a formal examination and treatment under the guidance of the doctor.