Heartburn is one of the most common discomforts of pregnancy, affecting roughly 44% of pregnant women overall. It becomes increasingly likely as pregnancy progresses, rising from about 26% in the first trimester to 56% in the third. So if you’re pregnant and dealing with a burning sensation behind your breastbone, you’re far from alone.
How Common It Is by Trimester
A large meta-analysis published in BMC Pregnancy and Childbirth pooled data from studies worldwide and found a clear trimester-dependent pattern. In the first trimester, about 26% of pregnant women experience reflux symptoms. That number climbs to roughly 33% in the second trimester and peaks at nearly 56% in the third. The trend reflects the accumulating hormonal and physical changes that make reflux progressively more likely as your due date approaches.
Beyond heartburn itself, acid regurgitation (the sensation of stomach acid rising into your throat) affects about 38% of pregnant women at some point during pregnancy. Many women experience both symptoms together.
Why Pregnancy Causes Heartburn
Two main factors are at work: hormones and physical pressure. The hormonal piece starts early. Rising levels of progesterone and estrogen weaken the muscular valve between your esophagus and stomach. This valve normally stays closed to keep stomach acid where it belongs. Research shows that even in early pregnancy, when the valve’s resting pressure appears normal, its ability to tighten in response to food and other stimuli is significantly reduced. In practical terms, the valve doesn’t clamp down the way it usually would after you eat, allowing acid to splash upward.
Progesterone also slows the movement of food through your digestive tract. That means your stomach stays full longer, giving acid more opportunity to escape upward.
The physical component becomes more relevant later. As your uterus grows, it pushes upward against your stomach and other organs. While some researchers debate how much this mechanical pressure alone contributes versus the hormonal effects, the combination of a relaxed valve and a compressed stomach in the third trimester explains why heartburn peaks so sharply in the final months.
Common Triggers to Watch For
Certain foods and habits tend to make pregnancy heartburn worse. Fatty, fried, or greasy foods slow stomach emptying, keeping acid production high for longer. Spicy foods, citrus, tomato-based sauces, chocolate, and coffee can all irritate the esophageal lining or further relax that already-weakened valve. Carbonated drinks can increase pressure inside the stomach.
Eating large meals is a reliable trigger. Your stomach has less room as pregnancy advances, so a big dinner is more likely to push acid upward. Eating within two to three hours of lying down is another common culprit, since gravity is no longer helping keep acid in your stomach. Tight clothing around the waist can add to the problem.
Lifestyle Changes That Help
Simple adjustments can meaningfully reduce symptoms for many women. Eating smaller, more frequent meals throughout the day keeps your stomach from overfilling. Staying upright for at least two to three hours after eating gives your stomach time to empty before you lie down. Elevating the head of your bed by a few inches (using a wedge pillow or raising the bed frame, not just stacking pillows) helps gravity work in your favor overnight.
Wearing loose-fitting clothing around your midsection, avoiding your personal trigger foods, and chewing food slowly can all make a noticeable difference. Some women find that chewing gum after meals helps, since it stimulates saliva production, which naturally neutralizes acid.
Medications Considered Safe in Pregnancy
When lifestyle changes aren’t enough, calcium carbonate antacids (the active ingredient in Tums) are widely considered acceptable during pregnancy. They work by directly neutralizing stomach acid and provide quick relief. Keep your total calcium intake from antacids below 2,500 mg per day. If you’re also taking iron supplements, take them at a different time of day, since calcium interferes with iron absorption.
If antacids alone don’t control your symptoms, acid-reducing medications that block acid production are the next step. Studies on famotidine (the active ingredient in Pepcid) have not reported an increased chance of birth defects. Proton pump inhibitors, which suppress acid more powerfully, have also been studied in pregnancy without showing clear harm. Your provider can help you decide which option fits your situation if over-the-counter antacids fall short.
Avoid antacids that contain sodium bicarbonate (baking soda), as high sodium intake can contribute to fluid retention. Antacids containing magnesium trisilicate in high doses should also be avoided in later pregnancy.
When Upper Abdominal Pain Needs Attention
Most pregnancy heartburn is uncomfortable but harmless. However, pain in the upper abdomen during pregnancy can occasionally signal something more serious, particularly preeclampsia or a related condition called HELLP syndrome. These conditions involve dangerously high blood pressure and can develop in the second half of pregnancy.
The key differences: preeclampsia-related pain tends to feel like intense pressure or a deep ache under the right ribs rather than a burning sensation behind the breastbone. It often comes with other warning signs like sudden swelling in the face or hands, severe headache, vision changes, or nausea that feels different from your usual digestive discomfort. If your “heartburn” feels unusually intense, doesn’t respond to antacids, or comes with any of these additional symptoms, contact your provider promptly.
Does It Go Away After Delivery?
For most women, heartburn resolves after giving birth. Once progesterone levels drop and the uterus is no longer compressing the stomach, the conditions that caused reflux disappear. However, about 20% of women continue to experience reflux symptoms even after delivery. Women who had significant reflux before pregnancy or who had particularly severe symptoms during pregnancy are more likely to fall into this group. If heartburn persists for more than a few weeks postpartum, it may be worth discussing with your provider, as it could reflect an underlying tendency toward reflux that pregnancy unmasked rather than caused.