n If at any point during or after sex you experience heavy spotting or bleeding, you should call your physician immediately. This is because "the uterus is quite large at this point and by its sheer weight can place too much pressure on your vessels," she adds. According to Valle, these are good examples of positions that avoid any abdominal pressure or weight on the belly. In addition to the mood swings and breast tenderness, you are also experiencing increased blood flow to the pelvis, Dr. Li...