This phenomenon is caused by excessive secretion of gastric acid, because in the late pregnancy, the fetus has grown larger, it will press on the stomach, this time will make the acid reflux, resulting in heartburn phenomenon. This is not a disease, so do not worry too much, and do not take any treatment, usually just pay attention to a healthy diet and maintain a good state of mind. If the heartburn is really strong, feel uncomfortable, you can also eat more alkaline food, which can relieve the symptoms of heartburn, but it should be noted that the diet must also be restrained, and usually do not eat too much, too greasy, too spicy.