In what week do you start having heartburn when you are pregnant?

Many people think it is late in pregnancy when the growing baby pushes the stomach up, but for a lot of women it starts much earlier and is caused by the hormone progesterone relaxing the muscle at the entrance to the stomach allowing acid to regurgitate back up into the esophagus. You can take antacids (ask your doctor) and it also helps to sleep propped up on two or three pillows (or place a wedge under the mattress) as laying down makes it worse.