A falling sensation in the stomach at 30 weeks of pregnancy may be caused by an enlarged uterus and preterm labor. 1. Enlargement of the uterus: As the pregnancy grows and enters the late stages of pregnancy, the pregnant woman’s abdomen usually becomes heavier, and the uterus will pull on the ligaments, producing a falling sensation similar to that of the uterus. 2. Preterm labor with precursor: If the stomach falls down at 30 weeks of pregnancy, accompanied by abdominal pain, vaginal bleeding and uterine contractions, preterm labor with precursor may have occurred. If a pregnant woman has a feeling of falling stomach at 30 weeks of pregnancy, accompanied by the above symptoms, it is recommended to consult a doctor in time, under the guidance of the doctor, improve the relevant examination, clarify the cause of the disease, and symptomatic treatment.