Placental Haematoma

Placental haematoma is a collection of blood in or around the placenta, found on ultrasound as a retroplacental, marginal or subchorionic clot, caused by rupture of maternal or fetal vessels at the placental edge or bed. It matters because the size and site decide the risk: small marginal or subchorionic clots usually resolve, but retroplacental clots and large collections raise the risk of abruption, growth restriction and loss.

• Risk factors: hypertension, thrombophilia, anticoagulant use, smoking, trauma, previous abruption, assisted conception.
• A large collection carries a worse outlook.
• Most small haematomas disappear by 20 to 28 weeks.

Women may have no symptoms, or light painless or painful vaginal bleeding, mild cramps and a soft non tender uterus. A large retroplacental clot causes pain and a tender uterus.

• Brown or fresh red bleeding.
• Normal vital signs in most.
• Differential diagnosis: placenta previa, placental abruption, vasa previa, cervical lesion, subchorionic haemorrhage, placental tumour, chorioangioma.
• Complications: miscarriage, abruption, growth restriction, oligohydramnios, preterm birth, preterm rupture of membranes, stillbirth, anaemia.

The approach is ultrasound with measurement and follow-up.

• Ultrasound: haematoma site (retroplacental, marginal, subchorionic), size in three dimensions with volume estimate, echogenicity (fresh clots are echogenic, old clots anechoic), placental position and thickness, fetal heart and growth.
• Haemoglobin, platelets, fibrinogen, coagulation screen; blood group and Kleihauer test in RhD negative women.
• Doppler of the umbilical artery and uterine arteries if growth is poor; cardiotocography from 28 weeks.
• Antiphospholipid antibodies and thrombophilia tests for recurrent or large haematoma.

The principle is observation with repeat scans for small stable haematomas, and admission for large, symptomatic or enlarging ones.

• Supportive: reassure for small haematomas; avoid strenuous work and intercourse while bleeding; teach to attend at once for heavy bleeding, pain or reduced movements; admit for large or retroplacental haematoma with bleeding; two cannulae in heavy bleeding.
• Pharmacological: ferrous sulphate 200 mg oral 8-hourly for anaemia; paracetamol 1 g oral 6-hourly (maximum 4 g in 24 hours) for pain; micronised progesterone 200 mg vaginal at night until 16 weeks for bleeding in early pregnancy with a history of miscarriage; tranexamic acid 1 g IV over 10 minutes for acute heavy bleeding; betamethasone 12 mg IM twice, 24 hours apart, between 24 and 34 weeks and 6 days if delivery is likely; magnesium sulphate 4 g IV over 20 minutes then 1 g per hour until delivery for 24 hours at most before 32 weeks; stop aspirin or enoxaparin only on specialist advice, and continue enoxaparin 40 mg subcutaneous daily when there is a clear thrombotic indication.
• Procedures: repeat ultrasound at 1 to 2 weeks and every 2 to 4 weeks until resolved; growth scans every 4 weeks from 28 weeks; delivery by induction or caesarean section at 37 to 38 weeks, earlier for acute abruption, growth restriction or fetal compromise.
• Special groups: RhD negative women give anti-D immunoglobulin 500 IU IM within 72 hours of any bleed after 12 weeks; women taking enoxaparin or warfarin need individual review before any change in dose.
• Red flags: heavy bleeding, constant abdominal pain, rapid enlargement of the collection, reduced fetal movements, fever, leaking fluid.
• Follow-up: ultrasound every 2 to 4 weeks until resolved; growth scans every 4 weeks from 28 weeks; haemoglobin every 4 weeks; cardiotocography weekly from 34 weeks if the collection persisted.