Common causes of bloating and abdominal swelling

Bloating — the sensation of fullness, tightness, or visible distension of the abdomen — is extremely common. In most cases it is functional, meaning it has no structural cause and is related to diet, gut motility, or irritable bowel syndrome (IBS). However, persistent or progressive abdominal swelling can be a sign of an underlying structural condition that requires investigation.

The most common structural causes of abdominal swelling in women include:

• Ovarian cysts: Particularly large cysts (5cm+) can cause visible abdominal distension. Ovarian cysts are common and usually benign, but require assessment to exclude malignancy.
• Uterine fibroids: Large fibroids can cause significant abdominal swelling. A fibroid uterus can reach the size of a 20-week pregnancy before symptoms become severe.
• Ascites: Fluid in the abdominal cavity, which can be caused by liver disease, heart failure, or — in women — ovarian cancer.
• Gallbladder disease: Gallstones and cholecystitis can cause right upper quadrant pain and bloating.
• Liver disease: Fatty liver, cirrhosis, and liver lesions can cause abdominal fullness and swelling.

Red flag symptoms that need investigation

The following symptoms alongside bloating or abdominal swelling should prompt investigation:

• Persistent bloating that does not resolve after 2–3 weeks
• Progressive abdominal distension — the abdomen is visibly getting larger over weeks or months
• Pelvic or abdominal pain
• Unexplained weight loss
• Change in bowel habit
• Feeling full quickly when eating
• Urinary frequency or urgency
• Postmenopausal bleeding

These symptoms — particularly the combination of persistent bloating, pelvic pain, and urinary symptoms — are the classic presentation of ovarian cancer. NICE guidelines recommend that women with these symptoms occurring more than 12 times per month should be investigated urgently.

What an ultrasound scan shows

An abdominal and pelvic ultrasound scan is the first-line investigation for bloating and abdominal swelling. It can identify:

• Ovarian cysts — size, morphology (simple vs complex), and laterality
• Uterine fibroids — number, size, and location
• Free fluid (ascites) in the abdomen and pelvis
• Liver abnormalities — fatty liver, cirrhosis, lesions
• Gallstones and gallbladder disease
• Kidney abnormalities
• Enlarged lymph nodes

At Sonoworld, a combined abdomen and pelvis ultrasound scan (£350) provides a comprehensive assessment of the abdominal and pelvic organs in a single 45-minute appointment.

When should you get a scan?

You should consider a scan if:

• You have persistent bloating that has lasted more than 2–3 weeks without a clear dietary cause
• You have any of the red flag symptoms listed above
• You have been told by your GP that you need an ultrasound but cannot wait for an NHS appointment
• You want reassurance that there is no structural cause for your symptoms

Frequently asked questions

What type of scan do I need for bloating?

An abdomen and pelvis ultrasound scan is the most appropriate first-line investigation for bloating and abdominal swelling in women. It assesses both the abdominal organs (liver, gallbladder, kidneys, spleen) and the pelvic organs (uterus, ovaries) in a single appointment.

Do I need a GP referral?

No. You can book directly at Sonoworld without a GP referral.