From the Guidelines
A small subchorionic hemorrhage is not considered "normal" in early pregnancy, though it is relatively common, occurring in a significant percentage of pregnancies, with an overall risk of miscarriage of approximately 12% 1. When considering the management of a small subchorionic hemorrhage in early pregnancy, it is crucial to prioritize the potential risks associated with the condition, including increased risk of miscarriage, preterm labor, or placental abruption, particularly with larger hemorrhages.
- The primary imaging modality for evaluating patients with vaginal bleeding in the first trimester is ultrasound (US), which can usually differentiate causes of first-trimester bleeding, including normal intrauterine pregnancy (IUP) with or without a subchorionic hematoma, nonviable IUP, gestational trophoblastic disease (GTD), and ectopic pregnancy 1.
- While many small subchorionic hemorrhages resolve on their own without complications, they should always be evaluated by a healthcare provider, and regular prenatal care and monitoring are essential to ensure the hemorrhage resolves and the pregnancy progresses normally.
- If vaginal bleeding occurs during pregnancy, it is recommended to contact a doctor promptly, and they may advise rest, avoiding strenuous activity and sexual intercourse until the bleeding resolves, as there is no specific medication to treat subchorionic hemorrhage directly 1.
- It is also important to note that pulsed methods of Doppler US should generally be avoided in the first trimester when there is a normal, or a potentially normal, IUP, and MRI may occasionally be helpful as a problem-solving tool 1.
From the Research
Subchorionic Hemorrhage in Early Pregnancy
- Subchorionic hemorrhage (SCH) is a condition where blood accumulates between the chorion and decidua basalis due to their separation 2.
- It is common in patients with threatened abortion in early pregnancy and is mainly detected by ultrasound 2.
- The occurrence of SCH may be related to several factors, such as abnormal coagulation function, autoimmune factors of pregnant women, assisted reproduction, drug use during pregnancy, and reproductive tract infection 2.
Clinical Significance of Subchorionic Hemorrhage
- Subchorionic hemorrhage is a frequent cause of first and second trimester bleeding and has a grave prognosis 3.
- The outcome of pregnancies with SCH correlates well with the relative and absolute size of the hematoma, severity of vaginal bleeding, change in hematoma size on follow-up examination, and presence of pain 3.
- Specific ultrasound features of SCH, such as a wrapping location with moderate size, may be indicative of increased risk of miscarriage or post-natal complications 4.
Size and Location of Subchorionic Hemorrhage
- Small hematomas on the placental surface are a common finding, but hemorrhage beneath or at the edge of the placenta is of greater concern 5.
- The site of the hematoma, rather than its size, is a critical factor in determining the outcome of the pregnancy 6.
- Hematomas associated with abortion are often found in the corpus or fundus of the uterus, rather than in the supracervical area 6.
Pregnancy Outcomes with Subchorionic Hemorrhage
- Subchorionic hematomas in early pregnancy are associated with an increased risk of spontaneous abortion 6.
- The presence of a hematoma does not affect the frequency of preterm delivery, but may be associated with other adverse pregnancy outcomes such as miscarriage, preterm birth, preeclampsia, and fetal growth restriction 2, 4.
- Large intrauterine hematomas may be acutely detrimental to maternal health in the second trimester, but may resolve with growth of the fetus and amniotic sac 5.