Exam Protocols and Documentation

Quick Answer: Follow AIUM/ISUOG view lists for fetal anatomy by trimester; document indication, technique, measurements, and limitations. A complete biophysical profile scores movement, tone, breathing, and amniotic fluid (plus NST). Registry items test what view comes next and what belongs in the report.

Obstetric Protocol Framework

Obstetric ultrasound is indication-driven. Common categories:

Second-Trimester Anatomy Minimum (Registry Focus)

Examiners expect knowledge of required planes, not optional glamour views:

• Head: Transtentorial (cerebellum), ventricular atria (<10 mm), CSP, falx, choroid.
• Face: Profile, lips (coronal), orbits if protocol.
• Spine: Longitudinal and transverse sweeps, skin line continuity.
• Heart: Four-chamber, outflow tracts (3-vessel trachea view concept).
• Abdomen: Stomach left, kidneys, bladder, cord insertion.
• Extremities: Three segments each limb when possible.
• Placenta/Cord: Location, relationship to os, vessel count at insertion.

If a structure is not seen, document why and recommend follow-up—registry questions punish silent omission.

First-Trimester Protocol Notes

• Confirm intrauterine gestational sac with yolk sac or embryo before dating.
• NT requires CRL 45–84 mm (per FMF/NTQR contexts; know range for items).
• Assess for multiples, subchorionic hemorrhage, and adnexal masses that affect management.

Gynecologic Protocol Framework

Transvaginal ultrasound is standard for:

• Endometrial thickness in postmenopausal bleeding
• Early pregnancy complications
• Adnexal mass characterization
• Follicular monitoring

Transabdominal may suffice for large fibroids or when TV is declined. Document empty bladder TV technique for endometrium vs. full bladder TA approach.

Biophysical Profile (BPP)

Each ultrasound component scores 0 or 2 (normal) for a max ultrasound score of 8; NST adds 2 for total 10.

Know modified BPP (NST + deepest pocket) used in some clinics.

Worked Scenario: BPP Fluid Score

Deepest vertical pocket measures 1.8 cm with otherwise normal components. Fluid scores 0, total ultrasound 6/8— triggers increased surveillance per institutional protocol. Registry may ask scoring, not management.

Limited vs. Complete Examination Designations

AIUM distinguishes limited examinations (focused question) from complete anatomy surveys. A limited scan for placental location does not require full cardiac outflow documentation—but the report must state the exam was limited to placental assessment. Registry traps present a single cardiac image from a previa follow-up and ask whether the complete anatomy survey is satisfied; the answer is no unless outflows were documented or limitation noted.

Documentation and Critical Results

Reports should communicate:

1. Clinical indication and gestational age source (LMP vs. early US).
2. Technique (TA/TV, Doppler use, fetal heart rate).
3. Findings by organ system with measurements (biometry, cervix, mass dimensions).
4. Impression with risk-appropriate language (never "happy fetal face").
5. Limitations and recommendations (MFM referral, repeat in 2–4 weeks).

Critical findings (e.g., omphalocele, previa covering os at term, ectopic with hemoperitoneum) require timely physician notification per department policy—protocols domain loves this distinction.

QA and Accreditation Hooks

The protocols domain includes:

• Image storage and retention policies
• Equipment maintenance logs
• Peer review sampling
• Correlation with outcomes (placenta accreta pathway)

Sonographers may be asked what satisfies AIUM practice parameter vs. optional research views.

Exam Traps

• Listing optional views as mandatory (e.g., ductus venosus for every NT exam).
• Forgetting cervical length documentation in indicated high-risk scans.
• Confusing AFI calculation steps (sum of four quadrants) with deepest vertical pocket for BPP.
• Marking a study complete when only four-chamber heart was obtained.

Protocols are the registry's way of verifying you think like a complete examiner, not a snapshot photographer.

Indication-Specific Minimum Data Sets

A limited third-trimester scan for fetal presentation documents lie, heart rate, placenta if visible, and fluid if clinically relevant—not a full cardiac survey. A detailed anatomy scan at 20 weeks requires systematic organ documentation even when indication is advanced maternal age only. Registry items may juxtapose indication text ("follow-up previa") with an image of four-chamber heart and ask whether outflow tracts are required for that indication—they are not unless the study is billed and described as complete anatomy.

Cervical Length Protocol Integration

Transvaginal cervical length belongs in indicated high-risk protocols: prior preterm birth, short cervix history, multiple gestation per institutional pathway. Measure straight line from internal os to external os with empty bladder; curved cervix may need multiple acquisitions. Funneling documents dilated internal os with membranes visible. A complete high-risk scan still lists why cervix was or was not measured when indication supports it.

Multidisciplinary Communication Standards

Structured reports enable MFM, radiology, and OB teams to act without ambiguity. Use gestational age source explicitly: "EDD by CRL 3/12/2026." When findings are critical, synchronous communication precedes final report transcription in most facilities. Sonographers initiating the call should state patient name, MRN, finding, and whether patient is stable—registry communication questions mirror this sequence.