Does the inferior facial angle predict respiratory status in Robin sequence infants?

Robin sequence (RS) is a rare congenital condition characterized by retrognathia, glossoptosis, and upper airway obstruction, with highly variable respiratory severity at birth. Prenatal measurement of the inferior facial angle (IFA) is used to support diagnosis, but its prognostic value for respiratory outcomes remains uncertain. This study assessed whether fetal MRI-measured IFA predicts early respiratory status in infants with RS. We conducted a retrospective monocentric study including consecutive infants with prenatal suspicion and postnatal confirmation of RS who underwent fetal MRI between 2009 and 2021. Respiratory status was assessed at delivery and at 6 months and categorized as room air breathing, noninvasive respiratory support, or intubation/tracheostomy. Five blinded operators independently measured the IFA and the anteroposterior skull size (APSS) on median sagittal MRI slice. Interobserver agreement was evaluated using intraclass correlation coefficients. Potential predictors of respiratory outcomes were analyzed using ordinal logistic regression. Among 43 infants, 72% required respiratory support at birth. More than half required ongoing respiratory assistance during early infancy. IFA values did not differ across respiratory outcome categories and were not associated with respiratory status at birth or during follow-up. Interobserver reliability was poor for IFA measurements, whereas APSS showed excellent agreement. In multivariable analyses, higher gestational age at birth was the only factor associated with reduced respiratory morbidity during the first 6 months.

These findings indicate that, although IFA is useful for diagnosing RS, it lacks reproducibility and prognostic value for respiratory outcomes, highlighting the need for delivery in specialized centers.

• In Pierre Robin sequence, no reliable prenatal predictor of respiratory status at birth exists. Although the inferior facial angle is used for prenatal diagnosis, its ability to predict neonatal respiratory severity is unknown.

• The inferior facial angle in prenatal fetal MRI shows limited predictive value for respiratory status at birth and during early infancy in infants with Robin sequence, with substantial measurement variability reducing its reliability as an isolated prognostic imaging marker.