Pages: 1 | 2 | 3 | 4 | Exit

Ultrasound Course Module 5
Biometry, Prenatal Diagnosis, and Doppler

Lesson 2: Biometry — Multiple Measurements (BPD/HC/AC/FL)

  1. Estimation of Fetal Weight
    • Hadlock Nomogram: HC, AC, FL
    • Shepard Nomogram: AC, FL
    • 3 weeks minimum interval for growth studies
    • Indirect measure of the variable of interest
    • Fair predictor (+/- 10-15 %) in normal fetuses
    • Poor predictor in LGA, SGA, or asymmetric fetuses
  2. Small Babies
    1. SGA (EFW < 5th percentile for ega)
    2. Etiology:
      1. 40-50% small but normal (no pathology)
      2. 30-40% uteroplacental etiology
      3. 10-20% maternal factors
      4. 5-10% fetal abnormality
  3. Growth — Restricted vs. Small-But-Normal
    1. HC/AC ratio:
    2. Highly predictive of IUGR in at-risk populations.
    3. Poorly predictive in normal populations.
    4. Reflects "head-sparing" effect.
    5. FL:AC — may reflect IUGR if abnormal.
      • If low, may reflect IUGR (Hadlock FP, Deter RL, Harrist RB, Roecker E, Park SK. A date-independent predictor of intrauterine growth retardation: Femur length/abdominal circumference ratio. AJR Am J Roentgenol 1983;141(5):979-84)
    6. Oligohydramnios.

      Normal umbilical artery systolic
      to diastolic ratio (S/D)


      Normal MCA of 52.9 cm seconds at
      32 weeks in a Duffy sensitized patient
    7. Predisposing maternal conditions.
    8. Doppler velocimetry:
      • Umbilical artery
      • Cerebral artery
  4. Large Babies
    1. U/S EFW is very unreliable for large fetuses.
    2. U/S EFW is a poor predictor of:
      • Abnormal labor progress
      • Shoulder dystocia
      • Actual birth weight (10-20% error rate)
    3. FL:AC — may reflect IUGR if abnormal.
      • if high. may reflect macrosomia (Hadlock FP, Deter RL, Harrist RB, Roecker E, Park SK. A date-independent predictor of intrauterine growth retardation: Femur length/abdominal circumference ratio. AJR Am J Roentgenol 1983;141(5):979-84)
    4. Consider:
      • Repeating glucose challenge (esp. w/increased fluid)
      • Early Induction for macrosomia is questionable

Back to Top

THERE IS NO COMMERCIAL SUPPORT FOR THIS ACTIVITY
Original Release Date: August 20, 2014 • Review Date: July 30, 2023 • Termination Date: July 31, 2026
Copyright © 2020 by Soli Deo Gloria MFM, LLC. All rights reserved. No part of this course may be reproduced in any form, by photostate, microfilm, xerography or any other means, or incorporated into any information retrieval system, electronic or mechanical, without the express written permission of Soli Deo Gloria MFM, LLC.