OBCast: Bleeding in Early Pregnancy and Threatened Miscarriage

Author: Ben Shepherd, MBBS FACEM DRANZCOG (Adv) (@OBCast, Emergency Physician Wollongong & Shoalhaven Hospitals NSW Australia) // Edited by: Alex Koyfman, MD (@EMHighAK); Brit Long, MD (@long_brit); and Manpreet Singh, MD (@MprizzleER)

emDocs is proud to host posts from Ben Shepherd, creater of OBCast. From Ben: “During my emergency medicine specialist training I spent time training towards and working as a rural GP obstetrician. It remains some of the most enjoyable and rewarding time I have spent in medicine. Coming back to emergency medicine it is obvious that my colleagues are often uncomfortable managing pregnancy-related problems, particularly those in the latter stages. The goal of ‘OBcast’ is to provide clear and practical information for ‘the reluctant obstetrician’ (emergency physician, rural GP) and improve confidence and the quality of care these families receive during what is both a stressful and wonderful time of their lives.”

Our first post looks at pelvic bleeding in early pregnancy and threatened miscarriage. Each post will contain a video presentation and downloadable slides for learning on the go.


Bleeding in early pregnancy is a common presentation to the ED and is a source of stress and concern for the newly expecting family. We are the experts in this aspect of obstetric care. and it is often our role to educate our junior providers. In this post we discuss the causes of vaginal bleeding in early pregnancy, the patient evaluation, and then focus on threatened miscarriage as its own entity.

It is important to understand the causes:

Patient Assessment

  • History
  • Exam
    • Vitals
    • Abdominal exam
    • PV/speculum:
      • Cervical changes/excitation
      • Evidence of adnexal mass/tenderness
      • Removal of cervical products
    • PoCUS
      • Free fluid?
      • IUP present?
      • Viability?
    • Evaluation
      • Bloods: Hb / Group & Hold / BhCG
      • TV Ultrasound
        • Location of pregnancy
        • Viability

Role of BhCG

  1. Diagnose or exclude pregnancy
  2. Discriminatory Zone: Initially used for diagnosis of ectopic pregnancy, but evidence is mixed/inconsistent
    • >1500 – TV ultrasound should visualise a normal IUP
    • >6000 – TA ultrasound should visualise a normal IUP
    • Serial BhCG measurement for PUL
  3. Follow up of BhCG to zero following GTD / failed pregnancy

Threatened Miscarriage

  • Definition = PV bleeding + viable IUP
  • Easily and rapidly diagnosed by PoCUS
  • Subsequent miscarriage rate 10-25%


  • Studied for potential ability to reduce subsequent miscarriage rate
  • 7 placebo-controlled trials, 696 patients
  • RR 0.57 (95%CI 0.38-0.85) for PO progestogen
  • Not used commonly at this stage, further studies underway

Subchorionic Haematoma

  • Perigestational haemorrhage
  • Fluid collects between uterine wall and chorionic membrane
  • Common cause of 1stand 2ndtrimester bleeding
  • Effect on Pregnancy
  • Increased early pregnancy loss
  • Evidence mixed regarding effect of size on risk

Effect on Late Pregnancy

  • Increase placental abruption
  • No other clear associations with pre-eclampsia, SGA, PTL

More #FOAMed:

Emergency Medicine Cases: Vaginal bleeding in early pregnancy

The Ultrasound Podcast: Pregnancy Ultrasound Part 1

The Ultrasound Podcast: Pregnancy Ultrasound Part 2

EM Basic: First-Trimester Vaginal Bleeding

EM in 5: Vaginal Bleeding in 1st TM Pregnancy

Brown EM: Asynchrony EM

CoreEM on Rhogam

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