Progesterone will not thicken the endometrium, progesterone will inhibit endometrial proliferation, so that the proliferative phase of the endometrium is converted to the secretory phase, to prevent endometrial lesions. The female body normally secretes progesterone and estrogen, and estrogen can promote the growth of the endometrium, making the endometrium thickening pregnancy. Progesterone can counteract estrogen and inhibit endometrial proliferation, which will not lead to endometrial thickening. Women in the follicular phase of the stage, the endometrium by the body of estrogen will gradually grow, thickening, such as mature follicles discharged and the formation of the corpus luteum in the body, the level of progesterone will rise significantly, the endometrium by the proliferative phase into the secretory phase. At this time, the endometrium will still continue to thicken, not progesterone effect, but after ovulation estrogen is still elevated caused. Progesterone can transform the endometrium, which has been stimulated by a single estrogen for a long time, into a secretory phase endometrium, inhibit endometrial proliferation, and can prevent endometrial lesions. If a woman has an abnormal endometrium, she should go to the hospital for treatment.