One question dominates this exam in the ED: in the pregnant patient, is there an intrauterine pregnancy? Everything else — fibroids, cysts, free fluid, the IUD hunt — is the supporting act.
Transabdominal first, always. It sees the big picture; the endocavitary probe zooms in when transabdominal can't answer.
Curated from the POCUS 101 Gynecology/Pelvic Ultrasound Made Easy and Obstetric/OB Ultrasound Made Easy guides. Their labeled anatomy images are the fastest way to learn the sagittal landmarks.
Abdominal/pelvic preset. Phased array works in a pinch. Endocavitary is a separate exam with opposite bladder rules.
A distended bladder is the acoustic window that pushes bowel away and lights up the uterus behind it. Empty bladder, lousy exam — scan before the Foley, before the void.
Probe just above the pubic symphysis in the midline, indicator toward the head, aimed slightly caudal into the pelvis.
Midline · indicator cephalad · sweep fully left and right
Landmarks from superficial to deep: bladder (anechoic triangle), then the uterus behind it — fundus, body, cervix — with the bright endometrial stripe down its center and the vaginal stripe trailing caudally.
Rotate 90° · indicator to the patient's right · sweep cervix to fundus
The uterus in cross-section behind the bladder. Sweep the whole organ — fibroids, masses, and gestational sacs off the midline only show themselves on a complete sweep.
Angle laterally from transverse · iliac vessels are the landmark
The ovaries sit anteromedial to the internal iliac vessels — oval structures with the "chocolate chip cookie" look from their follicles. Transabdominal views of normal ovaries are often limited; what you're really screening for is the big stuff: large cysts, complex masses, and the adnexal ring of an ectopic.
Both planes · the sac must be IN the endometrium of a normal-position uterus
A definitive IUP is a gestational sac containing a yolk sac or fetal pole, located within the endometrium. An empty sac alone doesn't count — a pseudogestational sac of an ectopic can fake it.
| Finding | Criteria | Means |
|---|---|---|
| Definitive IUP | Gestational sac + yolk sac or fetal pole, inside the endometrium | Ectopic effectively excluded in low-risk patients (heterotopic caveat) |
| Empty sac only | No yolk sac / pole | Not an IUP yet — could be early IUP or pseudogestational sac |
| Free fluid | More than trace in the cul-de-sac; any complex/echogenic fluid | In a pregnant patient, presume ectopic; unstable = OR conversation |
| Endometrial stripe | Measured sagittal, fundus to cervix midline | Thickened stripe (esp. postmenopausal bleeding) expedites GYN referral |
| Fibroids | Round, hypoechoic, often shadowing myometrial masses | Common; matters when symptomatic or distorting the picture |
| IUD | Bright echogenic line in the endometrial canal, midline both planes | Displaced or non-visualized IUD → formal imaging ± x-ray |
The empty bladder takes your acoustic window with it. Sequence the workup: pelvic POCUS first, then the catheter, then everything else.
An empty uterus with a positive hCG is the most dangerous normal-looking scan in the ED. It's a pregnancy of unknown location, and the default diagnosis is ectopic until someone proves otherwise.
Ectopics can generate an intrauterine fluid collection that mimics an early sac. No yolk sac, no IUP — don't let a sac-shaped shadow close the case.
A sac high in the cornu with a thin (<5–8 mm) rim of myometrium is an interstitial ectopic wearing an IUP costume — and it ruptures big. Confirm muscle on every side of the sac.
Heterotopic pregnancy is rare spontaneously but very real with IVF. In an assisted-reproduction patient, an IUP does not end the ectopic conversation.
Transabdominal answers "is there an obvious IUP, mass, or free fluid?" When it can't, the endocavitary exam, quantitative hCG trend, and OB/radiology take the baton. Knowing where your exam ends is part of the exam.
A starting template for the POCUS note. Text in brackets [ ] and pick-lists in { } are fields to complete. Save it as a SmartPhrase, then edit every field to match the actual study.
POINT-OF-CARE ULTRASOUND: TRANSABDOMINAL PELVIS
Indication: {first-trimester pain / bleeding : pelvic pain} [***]
hCG: {positive : negative : pending}
Exam type: Focused / limited, transabdominal
Operator: @ME@ Interpretation: independent, real-time
Probe: curvilinear
FINDINGS
- Uterus: {normal position / size : ***}
- Intrauterine pregnancy: {definitive IUP (yolk sac / fetal pole seen) :
no definitive IUP : empty sac only}
- Fetal cardiac activity: {N/A : present *** bpm : absent}
- Adnexa: {no mass : ***}
- Free fluid (cul-de-sac): {none : present [***]}
- Endometrial stripe: *** mm
IMAGE QUALITY: adequate / limited by [***]
Images saved and archived to [PACS / Qpath / ***].
IMPRESSION: {definitive IUP : pregnancy of unknown location - ectopic
not excluded, OB involved : ***}.
I personally performed and interpreted this study.
Electronically signed: @ME@ @TD@ @NOW@
Sample template only — not a validated institutional SmartPhrase. Verify wording, image-archival, and attestation requirements against your department's POCUS credentialing, coding, and compliance policies before clinical use. Documentation supports, but does not replace, the medical record and QA workflow.