Heartburn during pregnancy is primarily caused by hormonal changes and physical pressure from the growing uterus. Specifically:
- Pregnancy hormones, especially progesterone, relax the lower esophageal sphincter, a muscle valve that normally keeps stomach acid from flowing back into the esophagus. This relaxation allows acidic stomach contents to reflux, causing the burning sensation known as heartburn
- The enlarging uterus as the fetus grows presses upward on the stomach, increasing pressure and pushing stomach acid into the esophagus, which worsens heartburn symptoms, especially in the later stages of pregnancy
- Additionally, pregnancy hormones slow down digestion by relaxing muscles in the digestive tract. This delays stomach emptying, keeping food and acid in the stomach longer, which can contribute to reflux
Other factors that can exacerbate heartburn during pregnancy include eating large or fatty meals, lying down soon after eating, and certain foods like spicy or acidic items
. In summary, heartburn during pregnancy results from a combination of hormonal relaxation of the esophageal valve and mechanical pressure from the growing uterus, both of which promote acid reflux into the esophagus
