What is the initial management of a patient presenting to the emergency department with a miscarriage?

Initial Management of Miscarriage in the Emergency Department

The primary goal when evaluating a patient presenting with suspected miscarriage is to immediately rule out ectopic pregnancy through hemodynamic assessment, quantitative β-hCG measurement, and transvaginal ultrasound—never assume miscarriage without excluding ectopic pregnancy, as it remains the leading cause of first-trimester maternal death. 1, 2

Immediate Assessment and Stabilization

Vital Signs and Hemodynamic Status

• Assess vital signs immediately to identify hemodynamic instability, active hemorrhage requiring transfusion, or signs of peritoneal irritation suggesting ruptured ectopic pregnancy 1
• Check blood pressure, heart rate, and signs of hemorrhagic shock in all patients with vaginal bleeding and positive pregnancy test 2
• Any patient with peritoneal signs requires immediate surgical consultation, as this suggests possible ruptured ectopic pregnancy 2

Rh Status Determination

• Determine Rh status immediately upon presentation 2
• Administer anti-D immunoglobulin (300 mcg IM) to all Rh-negative women with first-trimester threatened abortion, complete abortion, or ectopic pregnancy, preferably within 72 hours 1, 3
• For pregnancy termination prior to 13 weeks' gestation, a reduced dose of 50 mcg may be used 3

Essential Diagnostic Workup

Laboratory Testing

• Obtain quantitative serum β-hCG on all patients with vaginal bleeding and positive pregnancy test to risk-stratify, though never delay ultrasound imaging for this result 2
• A single β-hCG measurement has limited diagnostic value; the primary utility is for comparison with follow-up measurements 1, 4
• If significant bleeding is present, obtain baseline platelet count, prothrombin time, partial thromboplastin time, and fibrinogen levels 2

Transvaginal Ultrasound

• Perform transvaginal ultrasound immediately as the primary diagnostic tool, regardless of β-hCG level—never defer ultrasound based solely on low β-hCG values 1, 2
• Transvaginal ultrasound provides superior resolution for early pregnancy compared to transabdominal approach 2
• Evaluate for intrauterine gestational sac with yolk sac or fetal pole, adnexal masses, and free fluid 1, 2

Physical Examination

• Perform speculum examination to assess for cervical lesions, polyps, inflammation, or active bleeding source 2
• Avoid digital bimanual examination until ultrasound excludes placenta previa in patients beyond first trimester, as examination before imaging can precipitate catastrophic hemorrhage 2

Diagnostic Algorithm Based on Findings

Intrauterine Pregnancy Confirmed (Gestational Sac with Yolk Sac or Fetal Pole)

• This essentially rules out ectopic pregnancy except in rare cases of heterotopic pregnancy 2
• Proceed with miscarriage management options if pregnancy is non-viable
• Initiate routine prenatal care if pregnancy is viable 4

Indeterminate Ultrasound (Pregnancy of Unknown Location)

• This is the highest-risk scenario requiring close follow-up, as 7-20% will ultimately be ectopic pregnancies 2, 4
• Never initiate treatment based solely on initial findings when ultrasound is indeterminate 1
• Arrange serial β-hCG measurements every 48 hours 1, 2
• Repeat ultrasound when β-hCG reaches 1,000-3,000 mIU/mL discriminatory threshold 2, 4

Risk Stratification by β-hCG Level with Indeterminate Ultrasound:

• β-hCG <1,000 mIU/mL: approximately 15% ectopic pregnancy rate 1
• β-hCG 1,000-2,000 mIU/mL: approximately 28% ectopic pregnancy rate 2
• β-hCG >2,000 mIU/mL: approximately 57% ectopic pregnancy rate 2
• β-hCG >3,000 mIU/mL with no gestational sac: 9% ectopic pregnancy rate, but requires immediate specialty consultation 2, 4

No Intrauterine Pregnancy Visualized

• Ectopic pregnancy must be excluded before treating as miscarriage 1
• If β-hCG >2,000-3,000 mIU/mL without intrauterine gestational sac, obtain immediate obstetrics/gynecology consultation 4
• Approximately 22% of ectopic pregnancies occur at β-hCG levels <1,000 mIU/mL, so low levels do not exclude the diagnosis 1, 2

Disposition and Follow-Up

Discharge Criteria for Non-Surgical Management

• Hemodynamic stability 1
• No signs of infection 1
• Reliable follow-up arranged 1
• Patient understanding of warning signs requiring immediate return 1

Mandatory Follow-Up Requirements

• Serial β-hCG measurements every 48 hours if diagnosis uncertain or pregnancy of unknown location 1, 2
• Repeat ultrasound when β-hCG reaches discriminatory threshold 2
• Follow-up within 24-48 hours for threatened abortion with concrete plans in place before discharge 2

Warning Signs Requiring Immediate Return

• Severe abdominal pain, especially with peritoneal signs
• Heavy bleeding (soaking more than 2 pads per hour)
• Fever or signs of infection
• Dizziness, syncope, or signs of hemodynamic instability

Critical Pitfalls to Avoid

• Never assume miscarriage without excluding ectopic pregnancy, especially with indeterminate ultrasound findings 1, 2
• Do not rely on β-hCG discriminatory thresholds alone to make management decisions—the traditional 3,000 mIU/mL threshold has virtually no diagnostic utility for predicting ectopic pregnancy 1, 2
• Avoid initiating treatment based solely on initial β-hCG levels without serial measurements or ultrasound correlation 1
• Do not discharge patients with pregnancy of unknown location without arranging close follow-up for repeat β-hCG or ultrasound 1
• Never defer ultrasound based solely on low β-hCG levels, as up to 36% of ectopic pregnancies present with β-hCG <1,000 mIU/mL 2
• Ultrasound may miss up to 74% of ectopic pregnancies initially, making serial β-hCG monitoring critical when initial ultrasound is non-diagnostic 2
• Do not rely on absence of risk factors to exclude ectopic pregnancy 2

Treatment Options for Confirmed Miscarriage

Once ectopic pregnancy has been definitively excluded and miscarriage confirmed, three management options exist: expectant management, medical management with misoprostol, or surgical evacuation. However, the initial ED visit focuses on diagnosis and exclusion of ectopic pregnancy rather than definitive miscarriage treatment, with specific management options typically coordinated with obstetrics follow-up 5, 6, 7, 8.