GERD: Causes Make an Appointment Refer a Patient Ask a Question Reviewed by Jeffrey B. King, MD (February 01, 2016) Each time you eat, stomach acids are released. Normally the lower esophageal sphincter acts as a guard to prevent stomach acids from backing up into the esophagus. An increase of the pressure in the stomach and/or relaxation of the muscle tone of the sphincter may cause reflux to occur. Factors that cause an increase in pressure are: Full stomach Obesity Lying down Bending forward Pregnancy Tight clothing. Factors that loosen the muscle tone of the valve can be caused by: Pregnancy Nicotine Alcohol, coffee, tea, Chocolate Mint Fatty foods. GERD: Symptoms Clinical Trials For more than 100 years, National Jewish Health has been committed to finding new treatments and cures for diseases. Search our clinical trials.