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First-Trimester Abdominal Circumference (Versus Crown Rump Length) Improves Precision in Inter- and Intraobserver
Yalda Afshar1, Rachel Gutkin1, Deborah Krakow1,2,3
1Department of Obstetrics and Gynecology, Los Angeles, California.
Summary
First-trimester abdominal circumference measurements offer the highest precision for dating pregnancies and calculating nuchal translucency (NT) multiples. This finding is particularly valuable in cases of maternal obesity or when sonography has technical limitations.
Area of Science:
- Maternal-Fetal Medicine
- Diagnostic Ultrasound
- Prenatal Diagnosis
Background:
- Accurate first-trimester biometric measurements are crucial for fetal dating and nuchal translucency (NT) assessment.
- Variability in measurements can impact diagnostic accuracy.
- Crown-rump length (CRL) is a standard for first-trimester dating and NT interpretation.
Purpose of the Study:
- To evaluate inter- and intraobserver variability of first-trimester biometric measurements and CRL.
- To compare the accuracy and precision of CRL with other biometric measurements for NT interpretation.
Main Methods:
- 356 singleton pregnancies underwent first-trimester ultrasound.
- Sonographers and maternal-fetal medicine specialists obtained independent measurements of CRL, standard biometry, and NT.
- NT multiples of the median were calculated using regression models.
Main Results:
- CRL showed the least variability, but abdominal circumference (AC) and head circumference (HC) had comparable variance.
- CRL and AC demonstrated the smallest standard deviation for NT interpretation.
- AC exhibited the most intra- and interobserver precision.
Conclusions:
- First-trimester abdominal circumference measurements provide excellent precision for dating and calculating NT multiples.
- AC is a potentially valuable biometric, especially in obese patients or with sonographic limitations.
Keywords:
crown-rump lengthfetal biometryfirst trimesternuchal translucencyprenatal screeningultrasoundMore Related Videos
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