The intense, burning sensation of heartburn, medically known as acid reflux, is a common experience during pregnancy. It occurs when stomach acid travels back up into the esophagus. While the physiological cause is well-understood, a persistent folk belief suggests that the severity of a pregnant person’s heartburn is directly linked to the amount of hair the baby has at birth.
Investigating the Connection: Myth vs. Correlation
For decades, the idea that a baby’s hair causes a mother’s heartburn was dismissed as folklore. However, a 2006 study out of Johns Hopkins University surprisingly found a correlation. Researchers tracked 64 pregnant women, asking them to rank their heartburn severity, and then compared those symptoms with the actual hair volume of their newborns, rated using photographs taken shortly after birth.
The results demonstrated a correlation: women who reported moderate or severe heartburn often gave birth to babies with average or above-average hair. Conversely, those who reported little to no heartburn tended to have babies with less than average hair. This finding validates the folk belief as a correlation, but it does not establish causation; the physical hair itself does not cause the burning sensation.
The correlation is explained by a shared biological mechanism driven by pregnancy hormones. The hormones circulating in the mother’s body are responsible for both the physiological changes that lead to heartburn and the modulation of fetal hair growth. Therefore, the heartburn and the hair are two separate effects of the same underlying cause.
The True Physiological Cause of Heartburn in Pregnancy
The science-backed reason for pregnancy heartburn centers on two main mechanisms: hormonal and mechanical. The primary hormonal driver is progesterone, which significantly increases throughout pregnancy. Progesterone acts as a smooth muscle relaxant, affecting the Lower Esophageal Sphincter (LES).
The LES is a muscular ring at the junction of the esophagus and the stomach that normally tightens after food passes through, preventing reflux. As progesterone levels rise, the LES muscle relaxes, making it less effective at sealing off the stomach. This relaxation allows acidic stomach contents to flow back up into the esophagus, causing discomfort.
The second cause is mechanical, becoming more pronounced in the second and third trimesters. As the fetus grows, the expanding uterus exerts increasing upward pressure on the abdominal cavity. This physical crowding compresses the stomach and forces its acidic contents back through the relaxed LES.
Managing Heartburn Discomfort
Managing heartburn discomfort during pregnancy often begins with simple adjustments to daily habits. Eating smaller portions multiple times a day instead of three large meals prevents the stomach from becoming overly full and pressuring the LES. It is also helpful to remain upright after eating; avoiding lying down for at least three hours before bedtime prevents gravity from assisting acid backflow.
Certain foods are known to exacerbate symptoms and should be avoided or limited, including spicy, fried, or high-fat foods. Caffeine, chocolate, and acidic foods like citrus fruits are common triggers. Elevating the head of the bed by several inches using blocks or wedges can help keep stomach acid in place overnight.
When lifestyle changes are insufficient, over-the-counter remedies like calcium-based antacids are generally considered safe options for quick relief. These medications work by neutralizing stomach acid to reduce esophageal irritation. Pregnant people should always consult with a healthcare provider before taking any medication to ensure it is appropriate for their specific circumstances.