Atonic Postpartum Haemorrhage

Atonic postpartum haemorrhage is bleeding after birth caused by failure of the uterus to contract and compress the placental site, with a soft boggy uterus above the pubis. It causes about 70 to 80 percent of postpartum haemorrhage. Causes include overdistension (twins, polyhydramnios, macrosomia), prolonged or rapid labour, oxytocin use, infection, retained tissue, general anaesthesia, uterine fibroids and exhaustion.

• Risk factors: grand multiparity, previous postpartum haemorrhage, chorioamnionitis, magnesium sulphate, tocolytic drugs, obesity, full bladder.
• A full bladder and retained clots stop the uterus contracting.
• Rapid response with massage and drugs stops most bleeding.

Women have heavy bleeding after the placenta delivers, with a large soft uterus that rises above the umbilicus and fills with clots, and signs of shock. Bleeding eases when the uterus is massaged and returns when massage stops.

• Soft, boggy uterus that is poorly defined on palpation.
• Bleeding is steady or in gushes with clots.
• Differential diagnosis: genital tract tear, retained placenta or fragments, uterine inversion, uterine rupture, coagulopathy, vaginal haematoma.
• Complications: haemorrhagic shock, coagulopathy, acute kidney injury, Sheehan syndrome, hysterectomy, maternal death.

The diagnosis is made by examination, with tests to measure the loss and exclude other causes.

• Palpate the uterine fundus (soft, above the umbilicus); empty the bladder; quantify blood loss.
• Pulse, blood pressure, shock index, urine output; inspect the placenta for completeness and the genital tract for tears.
• Haemoglobin, platelets, fibrinogen, prothrombin time, activated partial thromboplastin time, group and cross-match 4 units.
• Ultrasound for retained tissue or clots in the cavity.

The principle is uterine massage and a fixed sequence of uterotonics, then mechanical and surgical measures if bleeding continues.

• Supportive: call for help; two large-bore cannulae; Ringer's lactate 1 to 2 litres rapidly; oxygen; empty the bladder by catheter; massage the fundus until firm; bimanual compression (one hand in the vagina pushing the uterus up, the other on the abdomen); express clots; breastfeeding or nipple stimulation; transfusion for shock.
• Pharmacological: oxytocin 10 IU IM or 5 IU slow IV, then infusion of 40 IU in 1 litre Ringer's lactate at 250 mL per hour; ergometrine 0.2 mg IM (repeat after 15 minutes, maximum 1 mg in 24 hours); misoprostol 800 micrograms sublingual once; carboprost 250 micrograms IM every 15 minutes (maximum 8 doses); tranexamic acid 1 g IV over 10 minutes (repeat once after 30 minutes if bleeding continues); ampicillin 2 g IV plus gentamicin 5 mg/kg IV once daily if infection is suspected; ferrous sulphate 200 mg oral 8-hourly for 3 months.
• Procedures: uterine balloon tamponade (Foley or condom catheter filled with 300 to 500 mL sodium chloride 0.9 percent, removed after 12 to 24 hours); B-Lynch or other compression sutures; stepwise devascularisation (uterine then internal iliac artery ligation); embolisation where available; hysterectomy for uncontrolled bleeding.
• Special groups: hypertension, preeclampsia or heart disease avoids ergometrine; asthma avoids carboprost; heart disease uses oxytocin slowly as an infusion with no bolus; women who decline transfusion have cell salvage and early surgery.
• Red flags: blood loss above 1000 mL, pulse above 120 per minute, systolic blood pressure below 90 mmHg, bleeding after 3 uterotonics, fibrinogen below 2 g/L.
• Follow-up: observe uterine tone and bleeding every 15 minutes for 2 hours then hourly for 6 hours; haemoglobin at 6 and 24 hours; review at 6 weeks; plan the next birth with oxytocin ready and IV access.