Placental Abruption

Placental abruption is premature separation of a normally sited placenta from the uterine wall before birth, after 20 weeks, with bleeding behind the placenta. It results from rupture of maternal decidual vessels, often after hypertension, trauma or sudden decompression of the uterus. It is a leading cause of antepartum haemorrhage, stillbirth, preterm birth and maternal death from haemorrhage and coagulopathy.

• Risk factors: hypertension and preeclampsia, previous abruption, smoking, cocaine, abdominal trauma, preterm rupture of membranes, polyhydramnios, multiple pregnancy, thrombophilia, age above 35 years.
• The risk of recurrence is raised in later pregnancies.
• Fetal death is common in severe cases.

Women have sudden constant abdominal pain, vaginal bleeding (dark or fresh) or none, a hard tender uterus with frequent contractions, and fetal distress or death. Shock may be out of proportion to visible loss.

• Woody hard uterus with continuous pain.
• Fetal heart rate abnormal or absent.
• Differential diagnosis: placenta previa, uterine rupture, preterm labour, vasa previa, appendicitis, cervical lesion, fibroid degeneration, pyelonephritis.
• Complications: haemorrhagic shock, disseminated intravascular coagulation, acute kidney injury, Couvelaire uterus, postpartum haemorrhage, hysterectomy, fetal death, preterm birth, neonatal asphyxia, maternal death.

The diagnosis is clinical, and ultrasound is a poor test for abruption.

• Pulse, blood pressure, uterine tone and tenderness, fetal heart rate by Doppler and cardiotocography; speculum examination for cervical lesion after previa is excluded by scan.
• Ultrasound for placental site (to exclude previa), retroplacental clot, fetal viability and liquor; a normal scan does not exclude abruption.
• Haemoglobin, platelets, fibrinogen (below 2 g/L signals severe disease), prothrombin time, activated partial thromboplastin time, D-dimer, creatinine, group and cross-match 4 units; Kleihauer test in RhD negative women; bedside clotting test (a clot not forming in 10 minutes in 2 mL of blood).
• Urine output hourly; toxicology screen if drug use is suspected.

The principle is resuscitation, correction of coagulopathy and prompt delivery, with the route chosen by fetal state and maternal condition.

• Supportive: call for senior help; 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 the patient and fluids; continuous cardiotocography if the fetus is alive.
• Pharmacological: transfuse packed red cells early (aim for haemoglobin above 8 g/dL), 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; betamethasone 12 mg IM twice, 24 hours apart, between 24 and 34 weeks and 6 days if the mother and fetus are stable; 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 with distress 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; uterine balloon tamponade, compression sutures, uterine artery ligation or hysterectomy for uncontrolled bleeding; expectant care with admission for a small abruption below 34 weeks with a stable mother and fetus, and delivery at 37 weeks.
• 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; trauma needs a trauma team and cardiotocography for at least 4 hours.
• Red flags: shock, fibrinogen below 2 g/L, platelets below 50 x 10^9/L, urine below 30 mL per hour, fetal bradycardia or absent heart rate, expanding uterine fundus.
• 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; antenatal care in later pregnancy with aspirin 150 mg oral at night from 12 weeks to 36 weeks if preeclampsia was present; counselling on recurrence.