The posterior position of the uterus is not changed by lying on the back. The position of the uterus is mainly due to the pulling action of the ligaments, so in this case as long as the pulling action of the ligaments does not change, the position of the uterus will not change. Whether a woman sits, lies down or lies on her back, the position of the uterus is not affected. Posterior uterine position is also not harmful, do not worry too much. Both anterior and posterior uterus are normal uterine positions, so there is no need for special treatment. However, in women of childbearing age, it is more difficult to conceive with a posterior uterus than with an anterior one. In this case, when having sex, the woman can set a pillow under the buttocks, after sex should lie down for a while, do not get up immediately, can increase the chance of sperm into the uterine cavity, help to increase the rate of fertilization.