Detailed First-Trimester Scan (12w 0d to 13w 6d)
Early anatomical survey, nuchal translucency caliper calibration, nasal bone assessment, and aneuploidy risk calculation.
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Detailed Course Syllabus
Nuchal Translucency: Exact Calibration Protocols
Magnification, mid-sagittal criteria, caliper placement, and separating amnion from fetus.
Early Anatomic Checklist at 12–13+6 Weeks
Skull, brain, face, stomach, bladder, abdominal wall, and bilateral limbs.
Aneuploidy Markers & Genetic Counseling
Integrating NT, nasal bone, ductus venosus, and maternal biochemistry.
Increased nuchal translucency of 4.5mm. Nasal bone absent. Early structural mapping reveals no gross cranial or cardiac defect.
Definitively abnormal first-trimester findings establishing significantly elevated risk for Trisomy 21.
Immediate diagnostic invasive testing (CVS) with chromosomal microarray and early fetal echocardiogram scheduled at 16 weeks.
Learning Objectives
- Attain clinical proficiency in Fetal Medicine Foundation (FMF) criteria for nuchal translucency.
- Examine early intracranial anatomy: falx cerebri, choroid plexus 'butterfly' sign, and exclusion of anencephaly.
- Inspect the early facial profile for micrognathia, nasal bone presence, and frontomaxillary angle.
- Identify major early malformations: holoprosencephaly, omphalocele, gastroschisis, megacystis, and body stalk anomaly.
Clinical Relevance
Shifts detection of major congenital malformations and chromosomal anomalies from 20 weeks to 12 weeks, empowering parents with earlier decision-making and safer management options.
Clinical Guidelines Aligned
- FMF Guidelines on 11-13 Week Scan
- ISUOG Practice Guidelines: First-Trimester Scan
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