Concealed Placental Abruption

Concealed placental abruption is separation of the placenta in which blood stays trapped behind the placenta and within the uterus, with no visible vaginal bleeding. It is the less common form of abruption. It matters because the visible blood loss does not reflect the true loss, which can be several litres, so shock and coagulopathy appear in a woman with little or no bleeding to see.

• Risk factors: hypertension and preeclampsia, previous abruption, smoking, cocaine, abdominal trauma, polyhydramnios, multiple pregnancy, thrombophilia.
• Associated with higher fetal death and DIC rates than revealed abruption.
• Easily mistaken for labour, uterine rupture or an acute abdomen.

Women have severe constant abdominal pain, a hard tender uterus that enlarges with time, fetal distress or death, and shock out of proportion to visible loss. Vaginal bleeding is absent or minimal.

• Woody hard uterus; fundal height rising between examinations.
• Maternal pallor, tachycardia and low blood pressure.
• Differential diagnosis: uterine rupture, preterm labour, fibroid degeneration, acute appendicitis, pyelonephritis, ovarian torsion, ruptured liver in preeclampsia, ruptured ectopic in abdominal pregnancy.
• Complications: haemorrhagic shock, disseminated intravascular coagulation, acute kidney injury, Couvelaire uterus, postpartum haemorrhage, hysterectomy, fetal death, maternal death.

The diagnosis is clinical, with tests to find coagulopathy and exclude other causes.

• Pulse, blood pressure, uterine tenderness and size (mark the fundal height); fetal heart by Doppler and cardiotocography.
• Ultrasound for placental site and retroplacental clot (often not seen), fetal viability and free fluid.
• Haemoglobin (may be normal early), platelets, fibrinogen, prothrombin time, activated partial thromboplastin time, D-dimer, creatinine, liver enzymes, group and cross-match 4 to 6 units; bedside clotting test.
• Kleihauer test in RhD negative women; urine output hourly.

The principle is to treat on the clinical picture, not the visible loss, with resuscitation and delivery without delay.

• Supportive: two large-bore cannulae; oxygen 10 to 15 L/minute; Ringer's lactate 1 to 2 litres rapidly; left lateral position; urinary catheter with hourly output; warm fluids; mark and record the fundal height every 30 minutes.
• Pharmacological: transfuse packed red cells early, with fresh frozen plasma 15 mL/kg and cryoprecipitate 10 units (or fibrinogen concentrate 2 to 4 g) when fibrinogen is below 2 g/L, and platelets one adult dose when platelets are below 50 x 10^9/L; tranexamic acid 1 g IV over 10 minutes, repeated once after 30 minutes if bleeding continues; calcium gluconate 1 g IV after every 4 units of blood; oxytocin 10 IU IM at birth then infusion of 20 IU in 1 litre sodium chloride 0.9 percent at 125 mL per hour for 4 hours; carboprost 250 micrograms IM every 15 minutes (maximum 8 doses) for atony, avoided in asthma; misoprostol 800 micrograms sublingual for atony; magnesium sulphate 4 g IV over 20 minutes then 1 g per hour for 24 hours for hypertension with severe features; labetalol 20 mg IV then 40 mg, 80 mg and 80 mg at 10 minute intervals (maximum 220 mg) for blood pressure 160/110 mmHg or more.
• Procedures: emergency caesarean section for a live fetus or maternal instability; vaginal delivery with amniotomy and oxytocin (2 mU/minute doubling every 30 minutes to 32 mU/minute) for fetal death with a stable mother and corrected coagulation; balloon tamponade, compression sutures, uterine artery ligation or hysterectomy for uncontrolled bleeding.
• Special groups: RhD negative women give anti-D immunoglobulin 500 IU IM within 72 hours, increased by 125 IU for each 1 mL of fetal red cells above 4 mL; women who decline transfusion need cell salvage and tranexamic acid.
• Red flags: shock, rising fundal height, fibrinogen below 2 g/L, platelets below 50 x 10^9/L, urine below 30 mL per hour, fetal bradycardia or absent heart rate.
• Follow-up: high dependency care for 24 hours; haemoglobin, platelets and fibrinogen 6-hourly until stable; ferrous sulphate 200 mg oral 8-hourly for 3 months; counselling on recurrence risk and aspirin 150 mg oral at night from 12 weeks in the next pregnancy.