Retroplacental Haematoma

A retroplacental haematoma is a collection of blood between the placenta and the uterine wall, caused by rupture of decidual vessels. It is the ultrasound picture of a placental abruption that is bleeding behind the placenta. It matters because it can enlarge over hours, cause fetal death and trigger maternal coagulopathy, so a small stable collection may be watched but a large or enlarging one is an emergency.

• Risk factors: hypertension and preeclampsia, previous abruption, smoking, cocaine, abdominal trauma, thrombophilia, preterm rupture of membranes.
• A large collection, or one that lifts much of the placenta, carries a high risk of fetal death.
• Ultrasound can miss abruptions, so a normal scan does not exclude it.

Women have constant lower abdominal pain, a tender hard uterus, backache and sometimes dark vaginal bleeding, although bleeding may be absent when the blood stays behind the placenta. Small collections cause no symptoms and are found at a routine scan.

• Uterine tone raised, with frequent small contractions.
• Fetal heart rate may be abnormal or absent.
• Differential diagnosis: placenta previa, uterine rupture, preterm labour, fibroid degeneration, pyelonephritis, appendicitis, subchorionic haematoma.
• Complications: haemorrhagic shock, disseminated intravascular coagulation, acute kidney injury, preterm birth, growth restriction, fetal death, postpartum haemorrhage, hysterectomy, maternal death.

The diagnosis is clinical, supported by ultrasound that shows the clot and excludes previa.

• Transabdominal and transvaginal ultrasound: crescent or lens shaped hypoechoic or isoechoic collection behind the placenta that elevates the placental plate; measure in three planes and record the placental site.
• Pulse, blood pressure, uterine tenderness, mark the fundal height; cardiotocography.
• Haemoglobin, platelets, fibrinogen (below 2 g/L signals severe disease), prothrombin time, activated partial thromboplastin time, creatinine, group and cross-match 4 units, bedside clotting test.
• Kleihauer test in RhD negative women; urine output hourly.

The principle is resuscitation and delivery for a large collection or instability, and close observation for a small one.

• Supportive: two large-bore cannulae; oxygen 10 to 15 L/minute if shocked; Ringer's lactate 1 to 2 litres rapidly; left lateral position; urinary catheter with hourly output; admit a stable woman for at least 48 hours and mark the fundal height 4-hourly.
• Pharmacological: transfuse packed red cells for haemoglobin below 7 g/dL or shock, with fresh frozen plasma 15 mL/kg and cryoprecipitate 10 units (or fibrinogen concentrate 2 to 4 g) for fibrinogen below 2 g/L, and one adult dose of platelets for platelets below 50 x 10^9/L; tranexamic acid 1 g IV over 10 minutes, repeated once after 30 minutes if bleeding continues; betamethasone 12 mg IM twice, 24 hours apart, between 24 and 34 weeks and 6 days; magnesium sulphate 4 g IV over 20 minutes then 1 g per hour until delivery for 24 hours at most before 32 weeks; 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; 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.
• Procedures: emergency caesarean section for fetal distress or maternal instability; vaginal delivery with amniotomy and oxytocin (2 mU/minute doubled every 30 minutes to 32 mU/minute) for fetal death with a stable mother and corrected clotting; balloon tamponade, compression sutures, uterine artery ligation or hysterectomy for uncontrolled bleeding; delivery at 37 weeks for a small stable collection.
• 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.
• Follow-up: growth scans every 2 weeks; haemoglobin every 4 weeks; ferrous sulphate 200 mg oral 8-hourly for 3 months; aspirin 150 mg oral at night from 12 weeks to 36 weeks in the next pregnancy.