Heartburn is a painful burning sensation experienced behind the sternum (breast bone). Heartburn is a common condition experienced during pregnancy. Pregnancy can increase stomach acid reflux episodes frequently. Heartburn is experienced when the stomach acid contents flow into the esophagus due to the dysfunction of the lower esophagus sphincter (LES) muscles present in the gastroesophageal junction. It is identified that the presence of the hormone progesterone in circulation can relax the lower esophageal sphincter muscle. During the third trimester of pregnancy, heartburn and dyspepsia are observed more frequently. The enlargement of the uterus exerted pressure on the LES muscles which also causes heartburn.
Genesis of Heartburn during Pregnancy
About 80 percent of pregnant women suffer from heartburn. The exact pathogenesis of the heartburn during pregnancy is unclear yet. Scientist assumes that presence of hormones, especially progesterone in high levels in circulating blood can be a causative factor of heartburn. The basal lower esophageal sphincter muscles pressure does not change in the first trimester of pregnancy. But in later two trimesters the pressure of the LES muscles decreases gradually after 36 weeks of gestation and rebounds to normal range after 1 to 4 weeks postpartum. Progesterone in circulating blood along with the presence of oestrogen hormone relaxes the LES muscles. It decreases the pressure in the LES muscles. Progesterone also affects the gut motility and delay gastric clearance. In the study conducted by Weyermann et al., shows that more than 80 percent experience heartburn in the third trimester. In late pregnancy, heartburn is caused due to physical pressure exerted by the baby on to the LES muscles.
Symptoms of heartburn during pregnancy
The physiological changes occurring due to the heartburn consist of decreased gastrointestinal motility, which in turn increases the gut transit with increased water absorption. This causes leads to constipation. The bacterial infection causes reflux of bile into the stomach, especially due to Helicobacter pylori incompetence. The symptoms nausea and vomiting are observed in first trimester of pregnancy. Gastroesophageal reflux occurs through all the three trimesters of pregnancy. During pregnancy, the amount of hormone relaxin in the circulating blood increases. This reduces the gastric and small intestine motility through a nitric acid mediated mechanism. Epigastric pain is reported during pregnancy due to gastroesophageal reflux diseases, gastritis and peptic ulcer disease. Nausea occurring during pregnancy is with or without vomiting in the second and third trimester may be due to gastroenteritis and peptic ulcer disease. Heartburn is mostly seen in pregnant women who have a history of it before pregnancy. This heartburn further extends to early postpartum heartburn.
Diagnosis of Pregnancy Heartburn
Pregnant women experience a burning sensation behind the sternum and it further extends to the throat and the neck. The esophagus lacks protective lining that prevents it from the corrosive effects of gastric acid. This leads to the inflammation of the esophagus when acid reflux into the esophagus. By changing the eating and sleeping patterns and usage of mild medications heartburn can be controlled. In severe heartburn, upper esophageal endoscopy is done to diagnose the heartburn discomfort. This technique is widely used for the diagnostic purpose by carefully monitoring blood pressure and oxygen of the mother because it does not cause any harm to the fetus or mother. Other diagnostic techniques like barium radiography are not used because the radiation can cause harm to the fetus. FDA has classified all the drugs prescribed for heartburn based on their effect on the fetus into different categories (Category A, B, C, D, X). All medications are administered only by safely monitoring the symptoms after the first trimester.
Treatment of Heartburn during pregnancy
The heartburn experienced in pregnancy is normally modulated by dietary and lifestyle modifications. Prolonged occurrences of heartburns are due to gastroesophageal reflux diseases and only at chronic heartburn conditions, it is treated. As the first line treatment, antacid is prescribed for the treatment of heartburn. During pregnancy, antacids containing bicarbonate are not prescribed due to the side effects caused to mother and fetus metabolic acidosis and fluid overload. Antacids prescribed during pregnancy shows side effects like constipation, diarrhea or muscle cramps and interfere with the absorption of some food and supplements. Magnesium and aluminum contained antacids are safer to use during pregnancy than other antacids. The H2RA drugs are commonly used for the treatment of heartburn during pregnancy. Cimetidine, ranitidine, famotidine and nizatidine are the four FDA approved drugs used for heartburn during pregnancy. Proton pump inhibitors (PPIs) are other safely used drugs to reduce esophageal inflammation due to chronic heartburns. But during pregnancy PPI drugs are not prescribed because they have shown fetal toxicity in the FDA drug studies and it is classified into the class c category of drugs. The lifestyle and dietary modifications taken to prevent and reduce the onset of reflux episodes are:
- Limit the intake of spicy, fried and fatty foods
- Sit upright for atleast one hour after a meal.
- Taking smaller several meals instead of regular three big meals consumed by normal people.
- Drinking fluids between, rather than with meals.
- Keeping head raised by 2 to 3 inches of bed.
- Less consumption of carbonated drinks and caffeine contained beverages.
- Avoid smoking and alcohol consumption during pregnancy.
Lifestyle and dietary modification can prevent reflux episodes in pregnancy effectively. It can prevent the further onset of the heartburn during the second and third trimester.
Heartburn is a common symptom associated with pregnancy. The high amount of progesterone and oestrogen in circulating blood causes decrease in pressure of the LES muscles triggering acid reflux. The enlargement of uterus also exerts pressure on the LES muscles and stomach. This also has been identified as a cause of heartburn during pregnancy. The heartburn resolves usually after delivery, but severe heartburn can extend as postpartum heartburn also. Heartburn can be controlled by simple dietary and lifestyle modifications effectively. Serious reflux episodes are rare during pregnancy. The symptomatic gastroesophageal reflux is managed by proper medication that doesn’t harm the fetus. But good lifestyle and dietary habits to prevent the onset of reflux episodes and other gastroesophageal disorders.