There are three main causes of endometrial thinning: 1, women’s ovarian hypofunction or thyroid function abnormalities cause endometrial thinning, female endometrial growth depends on estrogen support, if various hormone disorders lead to lower estrogen levels, the female endometrium can not thicken and become thin. 2, patients repeatedly scraping or abortion and other uterine operations, resulting in serious damage to the endometrium or The endometrium is damaged or adhered, causing the endometrium to become thinner. After the endometrium is damaged or adhered, it loses its function and does not respond to the stimulating effect of estrogen in women’s bodies, so women’s endometrium cannot grow normally, so the endometrium will become thinner. 3. Women who take contraceptives for a long time, such as Daing-35, Eusyn or progestin, can make the endometrium thinner. The main component of birth control pills is progestin, which can counteract estrogen and make women’s uterine lining thinner.