Heartburn & Acid Reflux

What It Is & Why It Happens

Heartburn, characterized by a burning sensation in the chest and throat, is an extremely common pregnancy symptom affecting over half of all expectant mothers.

It is caused by a combination of hormonal and mechanical changes:

1. Hormonal Relaxation: During pregnancy, your body produces high levels of progesterone. Progesterone acts as a muscle relaxant, loosening smooth muscle tissues throughout the body. This includes the lower esophageal sphincter (LES), the circular muscle valve that seals the top of the stomach. When the LES relaxes, stomach acid can leak back upward into the esophagus, causing chemical irritation.
2. Slower Digestion: Progesterone also relaxes the stomach and intestines, slowing down digestion. This keeps food in the stomach longer, increasing gastric pressure.
3. Mechanical Pressure: As the uterus grows in the second and third trimesters, it pushes upward against the stomach, physically forcing stomach acid past the relaxed LES and into the esophagus.

Typical Timeline

Heartburn can start at any point, but it typically begins around Week 12 of pregnancy as progesterone levels stabilize at high levels. It increases steadily in frequency and intensity during the second and third trimesters as the baby grows larger. Heartburn usually peaks in intensity between Weeks 32 and 36, and often improves slightly when the baby “drops” (lightening) into the pelvis a few weeks before delivery, relieving direct pressure on the stomach.

Safe Comfort Measures

Lifestyle modifications are the safest and most effective first-line treatments for pregnancy heartburn:

• Dietary Tweaks: Avoid trigger foods that relax the LES or irritate the esophagus, such as spicy, greasy, acidic (citrus, tomato), fried, or highly seasoned foods. Limit carbonated drinks and caffeine.
• Portion Control: Eat small, frequent meals rather than three large ones to prevent the stomach from over-expanding.
• Timing: Avoid lying down for at least two to three hours after eating. Remain upright or take a gentle walk to assist digestion.
• Sleep Ergonomics: Elevate the head of your bed by 6 inches or use a wedge pillow to prop up your upper body, allowing gravity to keep stomach acid down.
• Hydration: Sip water between meals rather than during meals, as drinking large amounts of liquid with food can fill the stomach and trigger reflux.
• Safe Antacids: Calcium carbonate chewable antacids are generally safe for occasional use, but always consult your OB-GYN or provider before taking any over-the-counter medications.

When to Call the Doctor (Red Flags)

While heartburn is a normal discomfort, certain symptoms can point to other health issues. Contact your doctor immediately if:

• Heartburn is severe, constant, and interferes with your ability to eat, swallow, or sleep.
• You experience sharp or severe pain in the upper right side of your abdomen under your ribs (this is a key sign of liver stress associated with preeclampsia or HELLP syndrome, rather than simple acid reflux).
• Your heartburn is accompanied by sudden swelling in your face or hands, severe headaches, or vision changes.
• You vomit blood or have dark, tarry stools.