Pregnant Vaginal Bleeding Algorithm

  • Post category:Gynaecology

1. General Approach and Resuscitation


  • Start with initial resuscitation and ABCs depending on stability of the patient
  • Then rule-out ectopic pregnancy using pelvic ultrasound and HCG level
  • If ultrasound shows Intrauterine Pregnancy and no concern for ectopic, then evaluate for Spontaneous Abortion based on os and POC on exam
  • Final steps are to consider RhoGAM and other benign causes for vaginal bleeding

Unstable patient

  • Treat as ruptured ectopic
  • Clinical: Severe abdominal pain, peritonitis, hypotension/shock
  • FAST US: Intraperitoneal free fluid, complex adnexal mass
  • Type and Cross vs transfusion
  • Emergent Gyn consult for OR
Pregnant Vaginal Bleeding Algorithm
Pregnant Vaginal Bleeding Algorithm

2. Rule Out Ectopic Pregnancy


  • Based on results of Ultrasound → 3 possibilities:
    • If Ultrasound shows ectopic, Gyn consult for operative vs conservative management
    • If Ultrasound shows Intrauterine Pregnancy and no concern for heterotopic, eval for SAB
    • If Ultrasound indeterminate, classify into non-diagnostic or abnormal pregnancy based on ß- HCG level
Gestational AgeTransabdominal LandmarksTransvaginal LandmarksBeta-HCG Levels
4-5 Weeks+/- Gestational SacGestational Sac1000
5 WeeksGestational Sac +/- Yolk SacGestational Sac, Yolk Sac +/- Fetal Pole1000-2000
6 WeeksYolk Sac and Fetal PoleYolk Sac and Fetal Pole with Cardiac Activity10000-20000

Intrauterine Pregnancy

Ultrasound criteria for Intrauterine Pregnancy

  • See table for normal US appearance in pregnancy
  • Gestational sac + “double decidual sac” sign is earliest sign of pregnancy, although most believe it is the yolk sac

Pitfall: Pseudosacs

  • Pseudosacs are false sacs that can be confused with gestational sacs
  • Pseudosacs can occur in 10-20% of ectopic pregnancies
  • Centrally located → compared to eccentric location of true gestational sacs


  • Ectopic?
    • IUP in uterus essentially rules-out ectopic pregnancy unless concerned about heterotopic pregnancy

  • Heterotopic (ectopic + IUP) incidence:
    • General population: 1:4,000-30,000
    • Incidence in assisted reproduction: 1 in 100, therefore cannot exclude ectopic and further work-up needed in this population
  • Miscarriage
    • See Eval for Spontaneous Abortion section → patient is, at minimum having a threatened miscarriage

Indeterminate: Non Diagnostic

Discriminatory Zone (DZ):

  • Definition: β-HCG level at which it is assumed that all viable intrauterine pregnancies can be visualized by ultrasound
  • Level varies by institution and by experience of ultrasonographer
  • DZ level
    • Discriminatory zone for ß-HCG for transvaginal ultrasound is classically 1500-3000 (depending on institution)
    • New evidence shows discriminatory zone may actually be higher, even greater than 3500 in one study (Obstet Gynecol 2013;121:65–70) (N Engl J Med 2013;369:1443)
    • Caution in using a strict β-HCG cutoff to rule out a viable gestation

Indeterminate Ultrasound below Discriminatory Zone (DZ):

  • Ddx: early viable IUP vs nonviable IUP vs ectopic
  • If patient stable:
    • Gyn consult
    • Serial ß-HCG
    • Ultrasound repeat when ß-HCG above DZ
    • OK to discharge home if patient stable and reliable
  • Pitfall: Low ß-HCG
    • Ultrasound should still be obtained if ß-HCG is below discriminatory zone because may still be able to diagnose both IUP and ectopic (Level C ACEP Recommendation)

Indeterminate: Abnormal Pregnancy


  • Definition: Indeterminate U/S + β-HCG above the discriminatory zone
  • Ddx: Recent spontaneous AB, multiple gestation, molar pregnancy, ectopic pregnancy, viable or non-viable pregnancy
  • Indeterminate U/S + ß-HCG > DZ: Diagnostic of ectopic pregnancy? (Fertil Steril 1998;70:972-981)

Follow up

  • Follow-up needed in abnormal pregnancy because of increased likelihood of ectopic (Level B ACEP Recommendation Ann Emerg Med 2003;41:123)
  • Serial β-HCG
    • Standard approach for serial ß-HCG is a rise of 66% at 48hours (considered normal) although:
    • A normal rise may be seen in up to 15% of ectopics and an abnormal rise (<66%) may be seen in 15% of IUPs (Obstet Gynecol 1981;58:162-6)
    • Serial ß-HCG values at 48h: (Level B ACEP Recommendation Ann Emerg Med 2003;41:123)
      • 66% increase: IUP, Ectopic (15%)
      • Plateau: nonviable IUP, Ectopic Pregnancy (EP)
      • <66% increase: Ectopic, non-viable IUP, nl IUP(15%)
      • Decreasing: SAB, resolving ectopic
  • Ectopic pregnancy can resolve spontaneously by tubal abortion or regression, but >90% of women with ectopic and ß-HCG>2,000 will require surgery (CMAJ 2005;173(8);905-912)

Ectopic Pregnancy

Diagnosis of Ectopic Pregnancy

  • U/S signs suggestive of ectopic pregnancy (Ma OJ, First Trimester Pregnancy. In: Emergency Ultrasound, McGraw Hill. 2003, pp. 239)
    • Definite: Extra-uterine embryo with cardiac activity (seen in 15-20% of ectopic pregnancies)
    • Suggestive: Free pelvic or Intra-peritoneal fluid, tubal ring, complex adnexal mass
  • Incidence of heterotopic (ectopic + IUP) in
    • General population: 1:4,000-30,000
    • Incidence in assisted reproduction: 1 in 100, therefore cannot exclude ectopic and further work-up needed in this population

Treatment of Ectopic Pregnancy

  • Unstable
    • Treat as ruptured ectopic
    • Clinical: Severe abdominal pain, peritonitis, hypotension/shock ⇒ FAST US: Intraperitoneal free fluid, complex adnexal mass
    • Type and Cross vs transfusion
    • Emergent GYN consult for OR

  • Stable
    • Expectant management
      • Indication: unknown location pregnancy or suspected ectopic with low/declining β-HCG
      • Contraindications: Risk factors for rupture (increasing abdominal pain), not able to follow-up, and lack of timely access to medical care
    • Methotrexate
      • See table for indications
    • Surgery
      • Indications: Hemodynamic instability, contraindications to methotrexate, suspicion or risk factors for rupture, or failed medical therapy

Indications for Medical Therapy for Ectopic Pregnancy

□ Hemodynamically stable
□ Patient desires future fertility
□ Ability to return for follow-up
□ No contraindications to Methotrexate
□ Unruptured mass <3.5cm
□ No fetal cardiac activity
□ Quantitative ß-hCG < 6,00015,000

3. Evaluation for Spontaneous Abortion


  • Evaluate for spontaneous abortion in the patient with an IUP and vaginal bleeding
  • Classify into type of Spontaneous Abortion based on cervical OS and POC (Products of Conception)


  • Threatened miscarriage
    • Os closed and no POC
  • Inevitable
    • Os open and no POC
  • Incomplete
    • Os open and POC on exam in os
  • Complete
    • Os closed and POC expelled

Incidence of miscarriage: (BMJ 1997;315:32-4)

  • 21% of pregnant patients bleed before 20th week
    • 57% of those will miscarry
      • 80% of those will miscarry before 12 weeks
  • After detection of fetal cardiac activity, <5% of pregnancies with normal sonographic appearance will abort (Ann Emerg Med 2003;41:123,)

4. Rhogam ?

  • Indication
    • RhoGAM 50 mcg for Rh(-) women at time of first trimester pregnancy loss (Level B ACEP Recommendation Ann Emerg Med 2003;41:123,)
    • No recommendations for after first trimester, but standard dose is 300 mcg IM

5. Non Emergent Causes of Vaginal Bleeding


  • Diagnosis by U/S showing “snowstorm” pattern or cystic structures
  • Treatment is surgical evacuation with close monitoring of ß-HCG levels


  • Definition: spotting from implantation of embryo around the time of expected menses


  • Development of a gestational sac without embryonic structures
  • They may present with vaginal bleeding and abdominal pain
  • The diagnosis is confirmed with ultrasound. Treatment is misoprostol and/or uterine aspiration


  • Usually presents with abdominal or low back pain, not vaginal bleeding
  • Normal occurrence due to growth of the uterus
  • The majority have pain on the right side as the uterus tilts to that side