Can a subchorionic hematoma cause a miscarriage?

A healthy pregnancy is certainly a dream of most couples expecting a child. Experiencing pregnancy for the first time can be unnerving and would usually cost a lot of anxiety. Any changes to the body during the pregnancy, although subtle such as spots of blood, is easily recognised and raises concerns. This can explain why most women being pregnant for the first time are likely to pay more visits to a doctor to make sure nothing bad is happening. In this DoctorOnCall article, we will be talking on “can a subchorionic hematoma cause a miscarriage”.

Firstly, what is actually a subchorionic hematoma? A subchorionic hematoma is the bleeding beneath the chorion membranes covering the embryo. In short, it is accumulation of blood between the amniotic membrane and the uterine wall. Partial detachment of the chorion membranes from the uterine wall is the culprit of a subchorionic hematoma. A subchorionic hematoma or haemorrhage is the most common cause of a vaginal bleeding specifically during early pregnancy with most cases occurring within 10 to 20 weeks of gestational age.

Women experiencing a subchorionic hematoma typically show signs of vaginal bleeding but in some cases, may not exhibit any sign of bleeding and only be discovered during an ultrasound. Complaints of abdominal cramps or contraction is possible. The hematoma can be small or large but mostly are small ones. It is known what specific causes leading to a subchorionic hematoma but those at risk for acquiring one is:

  • Malformation of uterus
  • History of recurrent abortion
  • History of pelvic infections
  • Trauma
  • Preeclampsia marked by high blood pressure during pregnancy and risk for organ failure
  • In vitro fertilisation

Back to the main question of does subchorionic hematoma cause a miscarriage. The answer is not necessarily a yes. Although, there are few cases of patients with subchorionic hematoma shows increase risk for early pregnancy loss or risk for spontaneous abortion. If the subchorionic hematoma is detected in the early pregnancy much earlier, it can be an indicator of a much higher rate for a subsequent pregnancy failure. In general, a woman experiencing a subchorionic hematoma should not be worried of a possible complicated pregnancy as it is not a specific indicator to predict the pregnancy outcome.

Subchorionic hematomas only make one of the numerous causes of bleeding during pregnancy. Among causes includes cervical changes, implantation bleeding from the fertilised egg sticking into the womb, a miscarriage, an ectopic pregnancy which is characterised by the fertilised egg attached outside the womb, a molar pregnancy defined as abnormal growth of the placental tissues or an ongoing infection such as yeast infection. Since there are many other causes leading to a vaginal bleeding or blood spots, meeting healthcare professionals is necessary to rule out the possibility and to get the right diagnosis and treatment. Ultrasound and blood tests may be done to help physicians gain insight on the causes of the bleeding.

In the mild case of subchorionic hematomas, no specific treatment is required. They are advised to reduce activities which can cause strain on the uterus such as exercise and lifting heavy loads. Having bed rest can help to ease the symptoms and prevent increased blood pressure. Doctors might advise to take hormone medication such as progesterone to help prevent possible miscarriage. Healthcare professionals may teach the patient to monitor signs of early labour such as contractions or cramping so that they can reach the hospital on time for a preterm labour treatment. Regular follow-ups and frequent ultrasound checks are advised for these patients to monitor changes of the hematoma and the vaginal bleeding.