Let's talk about your stomach. At the top of your stomach, you have a valve that keeps food you just swallowed, as well as the acid your stomach produces to digest that food, down. During pregnancy, your body makes a hormone called progesterone. Progesterone relaxes this valve. With this valve relaxed, it’s much easier for stomach acid, and sometimes partially digested food, to rise back up into your esophagus. This causes a burning sensation in your chest and throat, which you've probably become pretty familiar with if you're pregnant. Heartburn, acid reflux and indigestion are all very common during pregnancy – largely because of the progesterone the body is producing. These conditions can all be worse if you’re pregnant with multiple babies, your baby is breech, or your baby is very large. There are ways to keep the heartburn at a minimum.