17 weeks of pregnancy belongs to the middle stage of pregnancy, pregnant women’s hard belly may be caused by contractions, personal constitution and other reasons, if rest is relieved, there is no need to worry too much. I, contractions: 1, pseudo contractions: hard belly may be caused by pseudo contractions, the appearance of time is not regular, and the degree of contractions is also relatively mild, infrequent episodes, generally will not produce pain, the cervical opening does not open large, often occur in pregnant women after a long time standing, through rest will often be relieved; 2, abnormal contractions: 17 weeks pregnant contractions gradually strengthen when the belly hard, may be a precursor to miscarriage During the attack, it is often accompanied by abdominal pain, vaginal bleeding, etc. This is an abnormal contraction, pregnant women should go to the hospital as soon as possible to check the obstetric ultrasound, to determine the fetal condition for fetal preservation treatment or termination of pregnancy. If the pregnant woman is too thin and has too little fat on her belly before pregnancy, with the growth and development of the fetus and the increase of pregnancy month, the uterus will gradually increase, and the belly may have hard symptoms, but the fetus has no abnormal development and the pregnant woman has no contractions. This situation may always exist. It is recommended that pregnant women should take timely nutrition, pay attention to rest and have regular maternity checkups.