Subchorionic Haematoma

What is it?

A subchorionic haematoma (SCH) is bleeding or the build-up of blood between the wall of the uterus and the sac or membranes which protect the developing fetus, or later in pregnancy, underneath the placenta itself.

Symptoms and diagnosis

Vaginal bleeding is a common symptoms in the first trimester. SCH is the most common cause of this. The bleeding can be anything from spotting to heavy bleeding with clots. There is not normally any pain, but some will experience mild cramping.

If you have any bleeding in early pregnancy you will be offered an ultrasound scan which will reveal the SCH if it is present. Occasionally the SCH cannot be seen on scan.

Sometimes patients have no symptoms and it is an incidental finding on ultrasound scan.

What is the cause?

The cause is unclear. Partial separation of the membranes around the fetus away from the wall of the uterus is thought to be the cause.

Risk factors for SCH include recurrent pregnancy loss, structural abnormalities of the uterus, pelvic infection, and patients who have had many previous children.

Should I be worried?

SCH, although not considered normal, is not an unusual finding and does not mean you will lose the pregnancy.

It can occasionally be associated with increased risk of miscarriage. This is more likely if:

• It is a larger SCH
• Older maternal age
• Earlier in pregnancy at diagnosis
• The location of the bleed is behind the placenta itself rather than just behind the membranes (this is only relevant later in pregnancy once the placenta has formed)

If the pregnancy continues, there is a small increased risk of some other complications including:

• early labour or early breaking of the waters around the baby
• placental bleeding and separation from the uterine wall later in pregnancy, also known as placental abruption
• blood pressure related issues later in the pregnancy,

Evidence for these complications is limited. Most pregnancies affected by a SCH progress normally, the SCH resolves on its own, and the pregnancy results in the delivery of a healthy baby with no additional complications.

What treatment do I need?

If you have had bleeding after 12 weeks of pregnancy and are rhesus negative, you will be offered an injection of anti-D immunoglobulin, side effects of which include: uncommon: chills; fever; headache; tiredness; skin reactions, rare/very rare: joint pain; difficulty breathing; low blood pressure; feeling sick; increased heart rate; vomiting

Evidence for other treatment is limited. You may be offered progesterone pessaries to insert into the vagina, although the benefits of this for SCH have not been proven. However, if you have had a previous miscarriage and have any bleeding in early pregnancy, progesterone pessaries can help improve the outcome of the pregnancy and will be offered. Side effects of progesterone include, commonly: sleepiness, pain/discomfort in abdomen, breast pain, constipation, tiredness, uncommon: rash/generalised itchiness, headache, dizziness, diarrhoea, vomiting, increased wind, joint pain, night sweats, feeling cold, itching at application site, incontinence. There is no evidence for bed rest.

Often conservative management alone with monitoring and a follow up ultrasound scan is all that is recommended.