In Utero Glossoptosis in Fetuses With Robin Sequence: Measurements From Prenatal MRI

Glossoptosis causes airway obstruction in patients with Robin sequence (RS), but little is known about the in-utero tongue. The purpose of this study was to assess shape and position of the fetal tongue on prenatal magnetic resonance imaging (MRI) to determine if this is predictive of postnatal RS.

Retrospective case-control study including fetuses with prenatal MRIs performed from 2002 to 2017. Inclusion criteria were (1) prenatal MRI of adequate quality, (2) live born and evaluated postnatally for craniofacial findings. Subjects were divided into groups based on postnatal findings: (1) RS, (2) micrognathia without RS, and (3) a gestational-age-matched control group with normal craniofacial morphology. Outcome variables were based on the prenatal MRI and included fetal tongue height, length, and width, tongue shape index (TSI, ratio of height to length), and observation of tongue touching the posterior pharyngeal wall.

A total of 116 subjects with mean gestational age at MRI of 25.6 ± 5.1 weeks were included: RS, n = 27 (23%); micrognathia, n = 35 (30%); control, n = 54 (47%). Tongue length was significantly shorter ( P = .009) and TSI was significantly larger in the RS group ( P < .0001). The tongue touched the posterior pharyngeal wall in 5 (19%) of the RS group and in no subjects in the other groups ( P < .0001).

In utero tongue shape and position were significantly different in fetuses with postnatal RS compared to those with isolated micrognathia and controls. Prenatal MRI tongue characteristics may be predictors for postnatal RS.