Final answer:
Upper stomach pain during the third trimester of pregnancy can be attributed to gastric reflux, decreased peristalsis leading to constipation, and increased pressure on the surrounding organs due to the growing uterus. Intestinal blockages and circulatory problems can also add to the discomfort.
Step-by-step explanation:
Upper stomach pain during the third trimester of pregnancy can have several causes. It's often due to the gastric reflux, or heartburn, caused by the upward, constrictive pressure of the growing uterus on the stomach. In addition, the decreased peristalsis that can contribute to constipation as pregnancy progresses can also lead to discomfort. These issues cause by the dramatic changes in maternal anatomy and physiology.
Further, the second and third trimesters of pregnancy bring about a significant enlargement of the abdominal region, accompanied by weight gain from the growing fetus, enlarged uterus, amniotic fluid, and the placenta. These contribute to increased pressure on the surrounding organs including the stomach, leading to discomfort or pain. The downward pressure of the uterus affects the urinary bladder as well, leading to frequent urination.
Intestinal blockages and circulatory problems in the legs can add to the discomfort. Clots may form in the legs due to pressure from the fetus on returning veins as they enter the abdominal cavity. All these conditions might culminate in upper stomach pain during the third trimester of pregnancy.
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