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Updated: Mar 28, 2026
A Novel Use of Three-dimensional High-frequency Ultrasonography for Early Pregnancy Characterization in the Mouse
Published on: October 24, 2017
Multicenter study of fetal crown-rump length measurement using 3D ultrasound in assisted reproductive technology
Ritsuko K Pooh1, Megumi Machida2, Kohtaro Uenishi2
1Fetal Brain Center, CRIFM Prenatal Medical Clinic, Matsushita Building 3F, 1-24, Uehonmachi 7, Tennoji, Osaka, 543-0001, Japan. ritsuko.pooh.brain@fetal-medicine-pooh.jp.
Purpose:
Accurate crown-rump length (CRL) measurement is fundamental for pregnancy dating and first-trimester screening. The Japanese standards established in 2003 using two-dimensional (2D) ultrasound require updating with modern imaging technology. This study aimed to establish new CRL reference standards for Japanese fetuses using three-dimensional (3D) ultrasound in precisely dated assisted reproductive technology (ART) pregnancies.
Methods:
We conducted a multicenter retrospective cohort study of singleton ART pregnancies from 11 Japanese fertility centers (2020-2023), with pregnancy outcomes documented in 2024. Inclusion required term delivery (≥ 37 weeks) and birth weight within the mean ± 1.5 SD. CRL measurements were performed centrally using standardized 3D ultrasound protocols. Polynomial regression models were used to generate reference equations.
Results:
Of 2,356 datasets, 1,598 pregnancies met the inclusion criteria. The mean maternal age was 36.3 ± 4.2 years. Reproducibility was excellent [intra- and inter-observer intraclass correlation coefficients (ICC) > 0.990]. No significant differences were found among ART methods in maternal age, gestational age at delivery, birth weight, or CRL growth pattern (p > 0.01). Third-degree polynomial regression produced reference curves for the 10th, 50th, and 90th percentiles. Compared with 2003 standards, CRL values were consistently larger (p < 0.001), and the growth trajectory showed no significant difference from the INTERGROWTH-21st international curve. Birth weights aligned with national standards, supporting general applicability.
Conclusion:
These updated 3D ultrasound-based CRL reference standards for ART pregnancies modernize Japanese practice and establish a refined framework for accurate gestational dating and first-trimester screening.
