All three of these problems relate to increased Progesterone hormone levels from pregnancy. Progesterone is a smooth muscle relaxant. Smooth muscle contraction is responsible for the movement of food through our intestines. Muscle relaxation leads to bloating and constipation.
Epigastric pain and heartburn relate to the same issue, relaxation of the smooth muscle that separates the valve between your stomach and esophagus. Relaxation leads to the reflux of stomach acid back into the chest and sometimes to the throat leading to vomiting or a chronic cough. Treatment ranges from dietary changes, such as avoiding fatty or spicy foods, mild antacids such as Tums or Maalox and prescription proton pump inhibitors like Prilosec, Prevacid, or Protonix, which need to be taken daily.