Subchorionic Haemorrhage

Subchorionic haemorrhage is active bleeding between the chorion and the uterine wall, producing vaginal bleeding that can be heavy, with or without a haematoma on scan. It arises from separation of the placental edge or implantation site. It matters because ongoing bleeding can cause anaemia, infection and pregnancy loss.

• Occurs most often at 6 to 12 weeks.
• Risk factors: previous miscarriage, uterine anomaly, assisted reproduction, anticoagulation, smoking.
• Bleeding often settles in 1 to 2 weeks.

Women report vaginal bleeding, sometimes with clots, and mild lower abdominal discomfort. The cervical os is closed and the uterus matches dates.

• Bleeding can be intermittent for weeks.
• No peritonism or shock unless bleeding is heavy.
• Differential diagnosis: threatened miscarriage, incomplete miscarriage, ectopic pregnancy, molar pregnancy, cervical lesion.
• Complications: miscarriage, anaemia, shock, intrauterine infection, abruption later, preterm birth.

The diagnosis is made on ultrasound with clinical assessment.

• Transvaginal ultrasound: fluid or clot between chorion and uterine wall, live embryo with fetal heart; measure the collection.
• Haemoglobin, blood group and Rhesus status; cross-match 2 units if bleeding is heavy.
• Speculum examination to exclude a cervical source.
• Urine pregnancy test; hCG only if the sac is not located.

The principle is observation, correction of anaemia and early treatment of infection.

• Supportive: reassure; avoid intercourse and strenuous activity until bleeding has stopped for 1 week; admit if bleeding is heavy; two large-bore cannulae and Ringer's lactate 1 litre over 30 minutes if unstable.
• Pharmacological: paracetamol 1 g oral 6-hourly as needed (maximum 4 g in 24 hours); micronised progesterone 400 mg vaginally twice daily until 16 weeks for women with at least one previous miscarriage; ferrous sulphate 200 mg oral 8-hourly for anaemia; if infection is present give ampicillin 2 g IV 6-hourly plus gentamicin 5 mg/kg IV once daily plus metronidazole 500 mg IV 8-hourly.
• Procedures: manual vacuum aspiration only if incomplete miscarriage develops with heavy bleeding.
• Special groups: Rhesus negative women give anti-D immunoglobulin 250 IU IM within 72 hours of the bleed.
• Red flags: heavy bleeding with dizziness, fever above 38 degrees Celsius, offensive discharge, severe pain, passage of tissue.
• Follow-up: review in 1 week; scan at 2 weeks to check viability and size; haemoglobin at 4 weeks; antenatal care with growth scan at 28 weeks if the collection was large.