CLINICAL ACTIONS:

Early Pregnancy Loss (EPL) is defined as a nonviable intrauterine pregnancy identified before 13 weeks gestation. ACOG states that ultrasound is the “preferred modality to verify the presence of a viable intrauterine gestation.” The AIUM Practice Parameter (see ‘Learn More – Primary Sources’ below) states

With transvaginal imaging, cardiac motion is usually observed when the embryo is 2 mm or greater in length. If an embryo less than 7 mm in length is seen without cardiac activity, a subsequent scan in 1 week is recommended to determine viability

Ultrasound Guidelines: The following criteria are derived from the 2012 Society of Radiologists in Ultrasound Multispecialty Panel on Early First Trimester Diagnosis of Miscarriage and Exclusion of a Viable Intrauterine Pregnancy

Diagnostic Criteria (Transvaginal)

• CRL of ≥7 mm and no heartbeat
• Mean sac diameter of ≥25 mm and no embryo
• Absence of embryo with heartbeat ≥2 weeks after a scan showing a gestational sac without a yolk sac
• Absence of embryo with heartbeat ≥11 days after a scan showing a gestational sac with a yolk sac

Suggestive, But Not Diagnostic (Transvaginal)  – Follow up at 7-10 days

• CRL <7 mm and no heartbeat
• Mean sac diameter of 16 to 24 mm and no embryo
• Absence of embryo with heartbeat 7 to 13 days after an ultrasound showing a gestational sac without a yolk sac
• Absence of embryo with heartbeat 7 to 10 days after an ultrasound scan showing a gestational sac with a yolk sac
• Absence of embryo for ≥6 weeks after last menstrual period
• Empty amnion: Amnion seen adjacent to yolk sac, with no visible embryo
• Enlarged yolk sac: >7 mm
• Small gestational sac in relation to the size of the embryo
  • <5 mm difference between mean sac diameter and CRL

SYNOPSIS:

Early pregnancy loss may present with clinical symptoms such as cramping and bleeding.  However, these findings can be present in normal, ectopic or molar pregnancies.  Ultrasound, if available, is a critical diagnostic modality but must be used in combination with clinical and laboratory findings, particularly serum β-hCG. For more information on recommended management when pregnancy location cannot be confirmed, see ‘Related ObG Topics’ below.

KEY POINTS:

• Document presence or absence of cardiac activity with M‐mode imaging or a 2D video clip
  • Pulsed Doppler ultrasound should not be used in the first trimester to “hear” the heartbeat
• ACOG highlights the limitations of the above guidelines including
  • Cut-offs may be overly conservative based on available evidence
• When taking care of patients with potential miscarriage
  • Consider a patient’s desire to have certainty of the loss prior to intervention
  • Discuss benefits of alternatives to surgical intervention as well as associated risks including
    • Spontaneous, unplanned passage of POCs
    • Potential anxiety
• Additional ACOG ‘suggestive’ criteria (not diagnostic) that also require follow up at 7 to 10 days
  • Slow fetal heart rate: <100 bpm at 5 to 7 weeks
  • Subchorionic hemorrhage

Learn More – Primary Sources:

ACOG Practice Bulletin 200: Early Pregnancy Loss 

AIUM Practice Parameter for the Performance of Limited Obstetric Ultrasound Examinations by Advanced Clinical Providers

Diagnostic criteria for nonviable pregnancy early in the first trimester. Society of Radiologists in Ultrasound Multispecialty Panel on Early First Trimester Diagnosis of Miscarriage and Exclusion of a Viable Intrauterine Pregnancy.

Related ObG Topics:

Managing Early Pregnancy Loss

Expectant Management vs Misoprostol for the Treatment of Miscarriage

Is Surgical Evacuation Needed Following Incomplete Miscarriage?

Diagnosing the Extrauterine Pregnancy-What You Need to Know

Pregnancy of Unknown Location – Next Steps