Ectopic Pregnancy Ultrasound Diagnosis

Step-by-step decision

Choose step by step as prompted; reaching an endpoint gives the management recommendation. You can go back a step or restart anytime.

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Full pathway

1. [Decision] Transvaginal ultrasound + beta-hCG
   Transvaginal ultrasound + beta-hCG findings? (TVUS is the gold standard, ~95% are tubal (ampulla most common). Hemodynamically unstable + suspected ectopic → do not wait for imaging, immediately resuscitate + surgery.)
   • Intrauterine sac seen (with yolk sac/embryo) → Intrauterine pregnancy (essentially excludes ectopic)
   • Adnexal mass separate from the ovary (blob sign / bagel-tubal ring / extrauterine sac ± embryo with heartbeat) → Adnexal mass → ectopic pregnancy
   • Hemoperitoneum (ground-glass/clot cul-de-sac fluid) + adnexal signs → Cul-de-sac blood → ruptured ectopic
   • Empty cavity, beta-hCG > discriminatory zone, no adnexal mass seen (PUL) → PUL → must exclude ectopic
2. [End] Intrauterine pregnancy (essentially excludes ectopic)
   A definite intrauterine sac seen (with yolk sac/embryo): essentially excludes ectopic (heterotopic pregnancy is rare — still beware coexisting intra- + extrauterine in ART patients); follow up as intrauterine pregnancy.
3. [End] Adnexal mass → ectopic pregnancy
   Adnexal mass separate from the ovary: blob sign (inhomogeneous mass, specificity ~99%) / bagel or tubal ring sign (empty sac with an echogenic ring) / extrauterine sac ± embryo with heartbeat = ectopic pregnancy; assess rectouterine pouch fluid; choose MTX or laparoscopy (salpingectomy/salpingostomy) by size/beta-hCG/symptoms. Differentiate the ring-of-fire from a corpus luteum (within the ovary, ipsilateral).
4. [End] Cul-de-sac blood → ruptured ectopic
   Hemoperitoneum (cul-de-sac/Morrison pouch fluid with ground-glass/clot appearance) + adnexal signs = ruptured ectopic; hemodynamically unstable → immediate resuscitation + emergency laparoscopy/laparotomy, do not delay surgery for imaging.
5. [End] PUL → must exclude ectopic
   Empty cavity + beta-hCG above the discriminatory zone + no adnexal mass = PUL: must exclude ectopic; serial beta-hCG + repeat TVUS (5–20% of ectopics are missed on the first scan); beta-hCG plateau/inappropriate rise or adnexal signs → suspect ectopic. Do not mistake a pseudosac (central, no double decidual sign) for an intrauterine pregnancy.

Source guidelines & references

• Ectopic pregnancy ultrasound signs (RadioGraphics; ISUOG VISUOG; UOG 2018 blob/bagel)

This pathway is our own synthesis of the decision logic in the guidelines above (not the guideline verbatim); thresholds and workflows change as guidelines update — in practice follow the latest guideline, your institution's protocol and the individual patient.

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