Obstetrics & Gynaecology Emergency Medicine Strong — NICE NG126 / RCOG GTG21

Ectopic Pregnancy & β-hCG Discriminatory Zone

Risk stratification for ectopic pregnancy based on β-hCG level, USS findings, and clinical features.

Score interpretation

Low Risk — Likely PUL or Early IUP 0–2

Low risk of ectopic. Likely early IUP or pregnancy of unknown location (PUL).

→ Serial β-hCG 48h (should rise ≥53% in 48h for IUP). Repeat TVUSS when hCG > 1500–2000 IU/L. Early pregnancy unit (EPU) follow-up. Patient education: A&E if acute pain.

Intermediate Risk — Possible Ectopic 3–5

Possible ectopic. hCG above or approaching discriminatory zone with PUL.

→ EPU review within 24–48h. Serial hCG and repeat TVUSS. If hCG rising but no IUP visible above discriminatory zone, treat as presumed ectopic. Methotrexate candidacy assessment (hCG < 3000, no fetal cardiac activity).

High Risk — Likely / Confirmed Ectopic 6–99

High risk of ectopic pregnancy — likely or confirmed.

→ If haemodynamically unstable: IMMEDIATE resuscitation — 2 large-bore IVs, crossmatch 4 units, urgent gynaecology/surgery. Emergency laparoscopy. If stable with adnexal mass: discuss salpingectomy vs salpingotomy. Methotrexate 50 mg/m² IM if criteria met and haemodynamically stable.

Interpretation bands for the Ectopic HCG. Apply clinical judgement and local guidance.

References

NICE NG126. Ectopic pregnancy and miscarriage: diagnosis and initial management. 2019.
RCOG Green-top Guideline No. 21. The Management of Tubal Pregnancy. 2016.

Curated clinical cross-links plus same-class fallbacks.

Drugs

Pathways

Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.

Score interpretation

References

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