The appearance of 15 weeks pregnant lying down abdomen will be hard may be physiological reasons, but also may be due to premature miscarriage or miscarriage and other pathological reasons, need to be specifically analyzed. 1. Physiological reasons: 15 weeks pregnant when the uterus has been gradually growing and expanding in all directions, when lying down if the pregnant woman to maintain the same position for too long or too much activity, causing the abdominal wall muscles to be pulled, or due to the body’s hormonal changes lead to pregnant women pseudo-contractions, may lead to pregnant women feel hard under the abdomen. 2. Pathological reasons: if the 15 weeks of pregnancy lying down abdomen will be hard, the duration of relatively regular, and more and more frequent, then we need to be vigilant about pre-eclampsia and may even lead to miscarriage, accompanied by obvious vaginal bleeding or abdominal pain symptoms. Once the emergence of 15 weeks pregnant lying on the abdomen will be hard there may be other reasons, the patient needs to consult a doctor in time, under the guidance of the doctor to improve the relevant examination, line targeted treatment.