Gastric Bypass Surgery ComplicationsThe potential risks for gastric bypass surgery complications can be dramatically reduced after your procedure by carefully following a bariatric diet and recovery plan. Talk with you health care team (surgeon, dietitian and nutritionist) for details.

Gastric bypass surgery is considered the safest and most effective bariatric procedure. It has been shown to help improve or eliminate many obesity-related medical problems, such as diabetes, cardiovascular disease, high blood pressure and more.

Together, our world-class surgeons along with food and nutrition experts focus on these issues to help you achieve long-term weigh loss success. First, you need to know if you qualify based on body mass index (BMI) and health issues. Second, its important for you to understand all the risks and complications of gastric bypass.

Gastric Bypass Surgery Complications

Long-term complications after gastric bypass can include, but are not limited to:

Vitamin and Mineral Deficiencies
About 30 percent of patients who have gastric bypass develop nutritional deficiencies (e.g., osteoporosis, anemia and metabolic bone issues). Because gastric bypass surgery changes the anatomy of the digestive system, both digestion and absorption of nutrition from food is altered.

  • First, the digestion of food is altered due to the “stomach” being bypassed. This means that food will no longer come in direct contact with gastric acid or pepsinogen.Gastric acid is required for vitamin B12 absorption. Pepsinogen helps break down dietary protein so the body can absorb it. A gastric bypass causes your body to absorb lower levels of both B12 and protein.
  • Second, absorption is altered because the part of your “small intestine” responsible for absorbing other vitamins and minerals is now bypassed. This means that your small intestine is absorbing less calcium, iron, zinc, copper and several B-vitamins from the food you eat. These nutritional deficiencies can be avoided by taking bariatric vitamin and mineral supplements.
After gastric bypass, careful nutrition follow-up is needed. What happens when patients fail to return for nutrition counseling, then present signs of nutrient deficiencies? What vitamins and minerals should be considered? Our nutrition experts can help you.

Malnutrition is a health condition caused by a lack of micro-nutrients (vitamins and minerals) or macro-nutrients (calories from protein, fat and carbohydrates). There are several types of malnutrition.The most basic type is called protein energy malnutrition. It results from a diet that lacks energy and protein due to a decrease in all major macro-nutrients.

Other types of malnutrition result from vitamin and mineral deficiencies (micro-nutrients). Gastric bypass patients may develop malnutrition because they take in too few nutrients or their body is unable to process the nutrients that they do take in. Signs of malnutrition complications after gastric bypass surgery varies but normally includes fatigue, dry skin, weakness and dull or brittle hair.

Talk with our nutrition experts to learn more about how they can help you manage complications that are related to nutrition deficiencies before and after surgery.

Stomal stenosis is a possible complication related to gastric bypass. This happens when there is a stricture (tightening) of the opening between the stomach and intestine. The most common symptoms include vomiting and difficulty swallowing. Most doctors believe excess scar formation and frequent vomiting cause stomal stenosis.

Ulcer formation after gastric bypass occurs in about 2% to 4% of weight loss surgery patients. Symptoms may include abdominal pain, nausea, vomiting of blood or black stool (occurs weeks after surgery). You can prevent ulcers by not smoking, avoid anti-inflammatory drugs and aspirin and take prescribed acid-reducing medication.

A hernia is any abnormal opening in the stomach wall. Internal hernias due to Roux-en-Y gastric bypass surgery are more common after “laparoscopic” gastric bypass than after “open” surgery. This results if the abdominal wall gets damaged during surgery and causes a weakness in the stomach lining. Incisional hernias occur when an incision does not heal properly, allowing the abdominal muscles to separate.

Early Complications of Gastric Bypass Surgery

Although major complications are uncommon after Roux-en-Y gastric bypass surgery, there are risks. Complications that can occur early on after gastric bypass include the following:

Stomach Leak
The most serious complication of Roux-enY gastric bypass surgery is leakage along the staple-line. Leaks are rare and usually appear within in the first 10 days of surgery.

Stomach leaks may be related to a surgical technique (incorrect staple line seal) or a patient who does not comply with postoperative surgery instructions. For example, patients who prematurely swallow food or fluids in the “early recovery” period. Studies show that about 10% of patients who undergo gastric bypass have stomach leak complications. Discuss this issue with your surgeon.

Bowel Obstruction
In some cases, bowel obstruction (blockage) may result from scar tissue or inflammation. This can cause stricture, or narrowing of the new connection between the stomach and intestine. Research shows that strictures normally develop 4 to 6 weeks after gastric bypass, and affect less than 5% of bariatric surgery patients.

Gastrointestinal bleeding after gastric bypass, though rare, is a potential complication that normally occurs several months after surgery. Because most bleeding is from areas along the staple-line, it is important for the surgeon to select the right staple size/height. The risk of bleeding after laparoscopic Roux-en-Y gastric bypass is reported to range from 1.1% to 4%.

Blood Clots
A blood clot (pulmonary embolism) is the most common early complication of gastric bypass. This happens when a clot travels from your leg veins upward to your lungs; blocking air from going in and out. Symptoms may include chest pain, coughing, rapid breathing/heart rate and shortness of breath. You can prevent a blood clot by walking, walking and more walking!

After surgery, you will have multiple small incisions on your stomach and in your belly button. You should clean your incision sites, especially your belly button with hydrogen peroxide or Alcohol pads at least once a day to prevent complications from infection. Call your surgeon if you experience excessive swelling, redness or yellow or tan discharge from the incision site or a fever > 101.0.

Other risks and complications may exist depending on your medical condition. Patients should carefully consider all of the risks and benefits before having gastric bypass surgery.

Risks of Roux-en-Y Gastric Bypass Surgery

If you’re considering Roux-en-Y gastric bypass surgery, we encourage you to discuss the benefits and risks with your surgeon.

Risks Related to Bariatric and Metabolic Surgery

  • Bleeding
  • Blood clotting (deep vein thrombosis)
  • Carbon dioxide embolism
  • Complications due to anesthesia and medications
  • Injury to the stomach, esophagus or other organs
  • Leaks from staple-lines
  • Pneumonia
  • Pulmonary problems
  • Pulmonary embolism
  • Shoulder pain
  • Spleen injury
  • Stenosis ( narrowing of a passage)
  • Stroke, heart attack or death
  • Ulcers


Risks and Complications After Gastric Bypass Surgery

  • Abdominal hernia
  • Back pain
  • Chest pain
  • Collapsed lungs
  • Constipation
  • Dehydration
  • Depression
  • Diarrhea
  • Difficulty swallowing
  • Dumping syndrome
  • Dyspepsia
  • Enlarged heart
  • Esophageal spasm
  • Esophageal dysmotility
  • Fatigue
  • Flatulence
  • Gallstones
  • Gas Bloat
  • Gastroenteritis
  • Gastrointestinal injury
  • Gastrointestinal reflux disease (GERD)
  • Gastrointestinal swelling
  • General abdominal pain
  • Hair loss
  • Headache
  • Hypertension
  • Increased gas
  • Inflammation of the esophagus
  • Inflammation of the gallbladder
  • Inflammation of the nasal passages
  • Inflammation of the sinuses
  • Inflammation of the stomach
  • Joint pain
  • Kidney tubular necrosis
  • Nutrition deficiencies
  • Stoma obstruction
  • Upper abdominal pain
  • Upset stomach
  • Weight regain


Patient Guide to Gastric Bypass Surgery