Antenatal ultrasound diagnosis of fetal micrognathia - validation and reproducibility of quantitative methods

Sep 28, 2026

Uploaded by James

Antenatal ultrasound diagnosis of fetal micrognathia may be performed subjectively or objectively. This retrospective study validated quantitative ultrasound methods in the second and third trimesters by assessing diagnostic performance, reproducibility, and how measurement variability affects classification. Mandible angle measurements from fetal facial proﬁle images were obtained between 18 and 28 weeks (2000–2018), comparing IFA, FNMA, MNMA, and FMA. Results showed FNMA as most reproducible and FMA as least, with variable diagnostic accuracy and potential misclassification.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages6

Reading Time15 min

AccessFree to download

Objectives

Methods

Study design and participants

Quantitative angle methods and validation approach

Reproducibility assessment

Impact of measurement variability

Results

Conclusions

Introduction

Fetal mandible development and relevance of micrognathia

Prenatal diagnosis and clinical importance

Ultrasound Obstet Gynecol 2026; 67: 67–72 Published online 20 November 2025 in Wiley Online Library ([wileyonlinelibrary.com](wileyonlinelibrary.com)). DOI: 10.1002/uog.70137. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. Antenatal ultrasound diagnosis of fetal micrognathia: validation and reproducibility of quantitative methods M. C. DENK1, M. BERTIN1 , V. DONADONO1 , L. KANGESU2,3 , A. YULIA1 , F. USHAKOV1 , P. P. PANDYA1,4 and R. NAPOLITANO1,4 1 Fetal Medicine Unit, University College London Hospitals NHS Foundation Trust, London, UK; 2 North Thames Cleft Service, Great Ormond Street Hospital, London, UK; 3 St Andrews Centre, Broomﬁeld Hospital, Chelmsford, UK; 4 Elizabeth Garrett Anderson Institute for Women’s Health, University College London, London, UK KEYWORDS: fetal ultrasound; mandible angle measurements; micrognathia; pregnancy; prenatal diagnosis; reproducibility | ABSTRACT
Objectives The antenatal ultrasound diagnosis of fetal micrognathia can be made subjectively or objectively. We aimed to validate quantitative ultrasound methods proposed for the diagnosis of fetal micrognathia in the second and third trimesters of pregnancy by evaluating their diagnostic performance, reproducibility and impact of measurement variability on diagnosis.
Methods This was a retrospective study analyzing the objective diagnostic accuracy, reproducibility and impact of measurement variability of mandible angle measurements from facial proﬁle images of fetuses with suspected micrognathia diagnosed antenatally using a subjective method. Fetuses were recruited at between 18 and 28 weeks’ gestation, at University College London Hospital, UK, between 2000 and 2018 . Four quantitative methods were compared: measurement of the inferior facial angle (IFA), the fronto –naso–mental angle (FNMA), the maxilla–nasion–mandible angle (MNMA) and the facial maxillary angle (FMA) . Methods were validated by calculating the percentage of cases in which the measured angles met the diagnostic criteria for micrognathia. To assess intra- and interobserver reproducibility, two sonographers, blinded to each other’s ﬁndings, measured each angle twice. Bland–Altman plots were used to calculate mean systematic differences and 95% limits of agreement (LoA) . Data were expressed in degrees and as percentages to account for the increase in fetal size with advancing gestation. The impact of measurement variability was evaluated by recalculating the diagnostic accuracy adding to the angle cut-off the intraobserver 95% LoA.
Results Of 132 fetuses diagnosed with suspected antenatal micrognathia, 84 cases had a known outcome | (termination of pregnancy (n = 56); fetal demise (n = 11); neonatal death (n = 4); live birth (n = 13)) and 48 were lost to follow-up. Fetal facial proﬁle ultrasound images were available for 49 cases in which reproducibility of the measurements was assessed (termination of pregnancy (n = 22); fetal demise (n = 5); neonatal death (n = 3); live birth (n = 6); lost to follow-up (n = 13)). FNMA was the most reproducible and FMA was the least reproducible measurement. Validation analysis showed that 14%, 100%, 88% and 90% of fetuses from our cohort met the criteria for the diagnosis of micrognathia using the cut-off criteria suggested in the original studies for IFA, FNMA, MNMA and FMA, respectively. The 95% LoAfor intra- and interobserver reproducibility were 3 .5% and 9.5% for FNMA, and 11.6% and 45.0% for FMA, respectively. When adding the intraobserver widest random error to the original study cut-offs, the percentage of fetuses meeting the criteria for diagnosis decreased to 0%, 87%, 49% and 45% for IFA, FNMA, MNMA and FMA, respectively.
Conclusions Current quantitative ultrasound methods to assess micrognathia antenatally have variable diagnostic accuracy and are no

FAQs

What was the study’s main goal for fetal micrognathia ultrasound diagnosis?

To validate quantitative ultrasound methods for diagnosing fetal micrognathia in the second and third trimesters by evaluating diagnostic performance, reproducibility, and the effect of measurement variability.

Which quantitative mandible angle methods were compared?

Four methods were compared: inferior facial angle (IFA), fronto-naso-mental angle (FNMA), maxilla–nasion–mandible angle (MNMA), and facial maxillary angle (FMA).

How did reproducibility differ among the angle measurements?

FNMA showed the most reproducibility, while FMA was the least reproducible measurement, based on intra- and interobserver limits of agreement.

Sep 28, 2026

Uploaded by James