Post-surgical complications after gastric sleeve surgery are relatively uncommon, but they do occur, and knowing what to look for could genuinely be a matter of serious consequence. This is not intended to frighten you. It is intended to give you the information to act quickly and appropriately if something does not feel right.
The most serious early complication: staple line leak
A leak from the staple line, where the stomach has been cut and sealed, is the most feared early complication of gastric sleeve surgery. It is rare, occurring in roughly 1 to 3 percent of cases depending on the centre and patient population, but it is a genuine medical emergency when it occurs.
A staple line leak allows stomach contents to escape into the abdominal cavity, causing infection and potentially sepsis. The symptoms that should prompt immediate medical attention include severe abdominal pain that is not controlled by prescribed pain relief, fever above 38 degrees Celsius, a racing heart rate, feeling extremely unwell in a way that feels sudden and different from normal post-operative recovery, and shoulder tip pain that is severe and does not settle.
If you experience these symptoms, particularly in the first two weeks after surgery, do not wait. Go to A and E or call 999. Tell them you have had recent bariatric surgery. Speed of treatment is critical.
Bleeding
Internal bleeding after gastric sleeve surgery can occur from the staple line or from the blood vessels around the operative site. Signs of significant internal bleeding include a rapid and worsening heart rate, dizziness or fainting, severe abdominal pain, and feeling extremely weak or unwell. Again, this is a medical emergency requiring immediate attention.
Some blood-tinged fluid from the drain, if one has been placed, is normal in the early hours after surgery. Bright red blood in increasing quantities from any drain or wound, or signs of haemorrhagic shock, require urgent assessment.
Deep vein thrombosis and pulmonary embolism
Bariatric surgery, like all major abdominal surgery, carries a risk of deep vein thrombosis. Blood clots that form in the deep veins of the legs can travel to the lungs, causing a pulmonary embolism. Post-operative anti-clotting medication and early mobilisation are the primary preventive measures.
Symptoms of a deep vein thrombosis include calf pain, swelling, warmth, and redness in the leg. A pulmonary embolism presents with sudden shortness of breath, chest pain, rapid heart rate, and in severe cases collapse. These symptoms require emergency treatment.
Later complications to be aware of
Beyond the immediate post-operative period, other complications can develop. Stricture, a narrowing of the sleeve that makes swallowing difficult, can occur and is typically identified by progressive difficulty eating solid foods or painful swallowing. This requires assessment and may be treated with endoscopic dilation.
Reflux and heartburn can develop or worsen after gastric sleeve surgery for some people. This is worth discussing with your surgical team if it is persistent or severe, as it may require medication management or in some cases surgical revision.
Nutritional complications from inadequate supplementation or monitoring, discussed extensively in our other articles, are among the most common longer-term issues. They develop slowly but can become serious if left unaddressed.
When in doubt, get checked
The overriding message is this: if something does not feel right after surgery, get it assessed. Do not minimise symptoms or wait for them to resolve on their own, particularly in the first four weeks post-operatively. Bariatric surgery teams are used to calls and presentations from post-operative patients and would always prefer to reassure you that everything is fine than to be called too late.
Sources
British Obesity and Metabolic Surgery Society (BOMSS): Complications after bariatric surgery. NICE: Complications and management of bariatric surgery. NHS: Weight loss surgery risks.
About this content
This blog is written by James and Kirsten, a couple from the UK who had gastric sleeve surgery together in March 2024.
We started this blog because we couldn't find any sources of content that details before surgery, the surgery and then life post surgery - so we decided to write one ourselves.
Everything on this site is based on our own experience and the research we have done along the way. It is not medical advice. Gastric sleeve surgery is a serious procedure and every patient's journey is different. Please always consult your own bariatric team or GP before making any decisions about your health or treatment.
Some posts on this site may contain featured or sponsored content, or affiliate links. Where this is the case, it will always be clearly stated at the top of the article. Our opinions are always our own.
Publish Date: 13 May 2026 | Last Reviewed: 7 June 2026 | Next Planned Review: 7 December 2027