Sudden stomach pain, dizziness and vomiting at 20 weeks of pregnancy may be caused by an enlarged uterus pulling on the ligaments, gastrointestinal colds and so on. As the weeks of pregnancy continue to increase, the uterus continues to grow and pull on the ligaments of the uterus, causing discomfort. This is a physiological phenomenon. However, it is important to consult a doctor in time to avoid delaying the condition. In addition, if the recent rain, fatigue, as well as contact with cold and flu and other triggers, causing gastrointestinal cold, may also appear abnormal. You should pay more attention to rest, drink some hot water, and do not eat any food for the time being. You should pay special attention to your diet during pregnancy and eat some well-digested and nutritious foods, fresh fruits and vegetables, nuts, milk and other foods. Sudden stomach pain, dizziness and want to vomit in 20 weeks of pregnancy may have other causes, and you should go to the obstetrics and gynecology department of the hospital in time to clarify the location of the pain, and timely treatment for the cause.