Document Type
Conference Proceeding
Publication Date
7-2024
Publication Title
Journal of Ultrasound in Medicine
Abstract
Objectives: The aim was to evaluate the validity of the current redating guidelines for pregnancies ≤9 6/7 weeks’ gestation. We postulated that visually apparent discrepancies between crown-rump length (CRL) measured by ultrasound (US) and CRL by last menstrual period (LMP) were statistically significant. Methods: This is a retrospective, cross-sectional study conducted between January 2019 and June 2023 at a tertiary referral center. Individuals who had singleton gestations between ≥6 0/7 and ≤9 6/7 weeks by known LMP were reviewed. For estimated gestational age (EGA) by LMP ≥6 0/7 and ≤8 6/7 weeks, a 3–5 day discrepancy between EGA by LMP and EGA by measured CRL was required for inclusion. For EGA ≥9 0/7 and ≤9 6/7 weeks, those with a 3 to 7 day discrepancy were included. All sonographic examinations were performed endovaginally by a single maternal-fetal medicine specialist. Statistical analysis was performed comparing the measured CRL based on US with the expected CRL based on LMP using the paired Wilcoxon signedrank test. Results: Two hundred nineteen sonograms met the study criteria, of which 141 (64.4%) had LMP EGA > US EGA and 78 (35.6%) had LMP EGA < US EGA. Of the total, 22 (10.0%) were of EGA 6 0/7–6 6/7 weeks, 39 (17.8%) were 7 0/7–7 6/7 weeks, 79 (36.1%) were 8 0/7–8 6/7 weeks, 79 (36.1%) were 9 0/7–9 6/7 weeks. Differences between expected CRL based on LMP and measured CRL determined by US were statistically significant across all gestational ages (p < .001). Intraobserver variability was 0.09. Conclusions: Our study showed a 3–5 day discrepancy is significant for EGA ≥6 0/7 and ≤8 6/7 weeks’ gestation, and a 3–7 day discrepancy is significant for EGA ≥9 /0/7 and ≤9 6/7 weeks’ gestation. Considering the clinical implications of accurate dating and the lack of robust data supporting the current redating guidelines, reevaluation of the guidelines for EGA ≤9 6/7 weeks is warranted.
Volume
43
Issue
Suppl 1
First Page
S183
Last Page
S184
Recommended Citation
Chen G, Choi C, Nguyen A, Brunk-Grady M, Nguyen T. Evaluation of current redating guidelines for pregnancies ≤9 6/7 weeks' gestation. J Ultrasound Med. 2024 Jul;43(Suppl 1):S183-S184. doi:10.1002/jum.16488
DOI
10.1002/jum.16488
Comments
American Institute of Ultrasound in Medicine Ultracon Meeting, April 6-10, 2024, Austin, TX