Sudden tummy ache with a big pregnant belly wearing tight clothes may be caused by simple pain in the soft tissue of the abdominal wall, induced uterine contractions, etc. It can be relieved by replacing loose clothing and taking medication. Wearing tight clothes with a big pregnant belly may irritate the skin muscle tissues, and may also affect the local blood circulation, causing pain in the soft tissues of the abdominal wall, resulting in sudden stomach pain. At this time, loose clothing should be replaced in time, and usually the symptoms of abdominal pain can be relieved soon. If wearing tight clothes for a longer period of time, it will lead to poor local blood circulation, affecting the pelvic blood circulation, which in turn induces uterine contraction, thus resulting in stomach pain. At this time, pregnant women should promptly change loose clothing, pay attention to rest, if the symptoms failed to ease, can be used under the guidance of the doctor to inhibit the contraction of drugs treatment. If the pregnant woman is pregnant wearing tights suddenly stomach pain, there may be other reasons, if the symptoms can not be relieved, it is recommended to consult a doctor in a timely manner, improve the relevant examination, clear the cause of the disease, symptomatic treatment.