Subinvolution of the Uterus

Subinvolution of the uterus is delay in the return of the uterus to its nonpregnant size, so that after 2 weeks the fundus is still palpable above the pubis and lochia remains red, heavy or offensive beyond the usual 4 to 6 weeks. It results from retained placental tissue, endometritis, fibroids, a full bladder or rectum, multiple pregnancy, poor breastfeeding and caesarean section. It matters because it causes prolonged bleeding and infection, and may signal retained tissue.

• Normal involution: fundus at the umbilicus at delivery, falling about 1 cm per day, not palpable abdominally by 2 weeks.
• Risk factors: retained products, infection, polyhydramnios, twins, grand multiparity, fibroids, prolonged labour.
• Most cases are treated with antibiotics and uterotonics.

Women have prolonged or heavy lochia with a pink or red colour for more than 2 weeks, clots, offensive discharge, lower abdominal discomfort and sometimes fever. The uterus is large, soft and sometimes tender.

• Fundus palpable above the pubis beyond 2 weeks.
• Red or brown lochia with a foul smell in infection.
• Differential diagnosis: retained placental tissue, endometritis, subinvolution of the placental site, fibroids, scar dehiscence, trophoblastic disease, return of menstruation.
• Complications: secondary postpartum haemorrhage, endometritis, sepsis, anaemia, chronic pelvic infection, hysterectomy.

The approach is clinical examination with ultrasound and tests for infection.

• Abdominal palpation for fundal height; bimanual examination for uterine size, consistency and tenderness; speculum for cervical os and discharge.
• Pelvic ultrasound: enlarged uterus, retained tissue, clots, endometrial thickness above 15 mm, fibroids.
• Haemoglobin, white cell count, C-reactive protein, high vaginal swab, urine hCG.
• Group and cross-match for heavy bleeding.

The principle is to give a short course of uterotonic and antibiotic therapy, and to evacuate retained tissue when found.

• Supportive: encourage breastfeeding and frequent suckling; empty the bladder and bowel; fluids; rest; stop tampons.
• Pharmacological: methylergometrine 0.2 mg oral 8-hourly for 3 days where available and not in hypertension; amoxicillin-clavulanate 625 mg oral 8-hourly for 7 days for infection; ampicillin 2 g IV 6-hourly plus gentamicin 5 mg/kg IV once daily plus metronidazole 500 mg IV 8-hourly for severe infection; tranexamic acid 1 g oral 8-hourly for 3 days for heavy bleeding; ferrous sulphate 200 mg oral 8-hourly for 3 months; paracetamol 1 g oral 6-hourly (maximum 4 g in 24 hours).
• Procedures: evacuation of retained tissue by suction under antibiotic cover and ultrasound guidance; myomectomy or hysterectomy rarely, for fibroids that block involution.
• Special groups: women with hypertension avoid ergometrine and use misoprostol 400 micrograms sublingual once instead.
• Red flags: heavy bleeding, fever above 38 degrees Celsius, foul lochia, severe pain, fundus not falling after 1 week of treatment.
• Follow-up: review at 1 week and 2 weeks with fundal height; ultrasound if bleeding persists; haemoglobin at 4 weeks; review at 6 weeks.