What is the cause of third trimester stomach pain? There are many reasons for stomach pain in the third trimester. First, physiological stomach pain, such as the uterus enlarges, pulling the surrounding ligaments will lead to stomach pain, this type of stomach pain mainly occurs when getting up, bending posture change, and other parts of the pregnant woman’s body ligament stretching will also cause stomach pain. These types of stomach pains do not need special treatment, they are normal phenomena. Second, uterine fibroids, uterine fibroids caused by the stomach pain will come more suddenly, and is a localized pain. This is a fixed place pain, this kind of situation needs timely medical attention. Thirdly, ovarian tumors can also cause stomach pain, mainly manifested as colic, abdominal discomfort, abnormal expansion of the abdomen, etc. This type of condition also requires immediate medical attention. Fourth, is ectopic pregnancy, if the third trimester stomach pain and accompanied by vaginal bleeding, it is likely to be ectopic pregnancy, which is a serious threat to the health of pregnant women, need to go to the hospital immediately to confirm the diagnosis, and rescue. Fifth, is a pre-miscarriage, third trimester stomach pain, may also be a pre-miscarriage, the main symptom is a slight lower abdominal pain, and the pain is paroxysmal, this situation should be promptly to seek medical attention.