Caesarean Wound Seroma

Caesarean wound seroma is a collection of clear serous fluid in the subcutaneous tissue at the caesarean incision, caused by the accumulation of lymph and tissue fluid in dead space. It occurs more often in obese women with a thick subcutaneous layer. It matters because it causes swelling and discomfort, may leak, and can become infected if it is not managed correctly.

• Risk factors: obesity, thick subcutaneous fat, diabetes, extensive tissue dissection, no closure of the subcutaneous layer (when it is thicker than 2 cm), electrocautery use.
• Usually appears on days 4 to 10.
• Most resolve without treatment.

Women have a soft, fluctuant, painless or mildly tender swelling along the incision, with clear or straw-coloured fluid draining from the wound. The skin is not red and there is no fever.

• Fluctuant swelling with a fluid thrill.
• Clear yellow discharge without pus.
• Differential diagnosis: wound infection, wound haematoma, early dehiscence, abscess, incisional hernia, lymphocele.
• Complications: wound infection, wound dehiscence, delayed healing, discomfort, recurrent fluid collection.

The diagnosis is clinical, with ultrasound to confirm and to exclude other collections.

• Inspect and palpate the wound for fluctuance and measure the swelling; confirm there is no redness, warmth or fever.
• Ultrasound: anechoic collection in the subcutaneous plane above the fascia.
• Aspirated fluid: clear, straw-coloured, no pus; send for culture if infection is suspected.
• Full blood count and C-reactive protein if fever or redness develops.

The principle is observation or aspiration, with antibiotics only when infection develops.

• Supportive: abdominal binder or firm dressing; keep the wound clean and dry; limit heavy lifting; monitor for redness or fever; reassure that most seromas resolve in 2 to 6 weeks.
• Pharmacological: paracetamol 1 g oral 6-hourly (maximum 4 g in 24 hours) for discomfort; no antibiotics for a clean seroma; flucloxacillin 500 mg oral 6-hourly for 7 days, or amoxicillin-clavulanate 625 mg oral 8-hourly for 7 days, if infection develops.
• Procedures: observation for small seromas; sterile needle aspiration for a large or tense seroma (not more than once or twice, to avoid introducing infection) followed by a pressure dressing; opening of the wound at the bedside and packing for a persistent or leaking seroma; drainage with a closed suction drain in theatre for a recurrent large collection.
• Special groups: obese and diabetic women have glucose control with insulin to keep glucose below 10 mmol/L to prevent infection.
• Red flags: redness, warmth, fever above 38 degrees Celsius, pus, increasing pain, rapid refilling, wound breakdown.
• Follow-up: wound review at 1 week and 2 weeks; ultrasound if the swelling persists beyond 4 weeks; review at 6 weeks.