Non-viable pregnancy (US) — First trimester
Educational tool based on NICE guideline NG126 (2023 update), using a more conservative approach than earlier recommendations.
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Interactive checklist
Answer the questions in order. The checklist applies NICE 2023 criteria and automatically shows guidance as you fill in the fields.
Recommended sequence (NICE)
- When performing an ultrasound scan to assess the viability of an intrauterine pregnancy, first look for fetal cardiac activity.
- If no cardiac activity is seen but an embryo is visible, measure the crown–rump length (CRL).
- Measure the mean gestational sac diameter (MSD) only if the embryo is not visible.
Follow-up
Minimum recommended follow-up interval (NICE 2023)
- •Transvaginal: minimum interval = 7 days
- •Transabdominal: minimum interval = 14 days
Always repeat under adequate technical conditions and consider dating uncertainty.
Limitations
Limitations / caution
- •Not validated for patients under 18 years.
- •Not applicable when ectopic pregnancy is suspected.
- •Does not replace clinical assessment; in instability/bleeding, prioritize emergency care.
- •Do not use LMP alone to decide when cardiac activity should be visible.
- •Cycle variability may lead to dating error.
- •Uncertain dating / very early scan.
- •Clinical–ultrasound discordance.
- •If diagnosing complete miscarriage without a prior scan confirming an intrauterine pregnancy, consider pregnancy of unknown location (PUL) and follow-up.
Disclaimer
Educational tool based on NICE guideline NG126 (2019, updated 2023). Does not replace individual clinical assessment.
References
- National Institute for Health and Care Excellence (NICE). Ectopic pregnancy and miscarriage: diagnosis and initial management. NICE guideline NG126. London: NICE; 2019. Updated 23 Aug 2023. Available at: https://www.nice.org.uk/guidance/ng126