obin sequence (RS), also known as Pierre Robin sequence, 1 is defined as the triad of micrognathia, glossoptosis, and upper airway obstruction. 2 A cleft of the secondary palate, although not required for the diagnosis, is present in approximately 50% to 90% of infants with RS. 3,4 RS occurs in 1 in 8500 to 20,000 live births. 5,6 The term RS describes a phenotype with diverse etiopathogenesis; RS may be initiated by intrauterine growth restriction or other nongenetically based stimuli, or as the result of more than 100 associated syndromes. 7 As a result, affected infants exhibit a wide spectrum of severity and associated congenital anomalies.Nonoperative treatment measures, including side or prone positioning, supplemental or positive airway pressure oxygen delivery, nasopharyngeal airways, or oral appliances with velar Background: Studies of infants with micrognathia, especially Robin sequence, are limited by its rarity and both phenotypic and diagnostic variability. Most knowledge of this condition is sourced from small, single-institution samples. Methods: This is a cross-sectional study including infants with micrognathia admitted to 38 Children's Hospital Neonatal Consortium centers from 2010 through 2020. Predictor variables included demographic data, birth characteristics, cleft, and syndrome status. Outcome variables included length of stay, death, feeding or respiratory support, and secondary airway operations. Results: A total of 1289 infants with micrognathia had surgery to correct upper airway obstruction. Mean age and weight at operation were 34.8 ± 1.8 weeks and 3515.4 ± 42 g, respectively. A syndromic diagnosis was made in 150 (11.6%) patients, with Stickler (5.4%) and Treacher Collins (2.2%) syndromes being the most common. Operations included mandibular distraction osteogenesis (MDO) in 66.3%, tracheostomy in 25.4%, and tongue-lip adhesion (TLA) in 8.3%. Patients receiving a tracheostomy had lower birthweight, head circumference, gestational age, and Apgar scores. Patients undergoing MDO were less likely to need a second airway operation compared with patients undergoing TLA (3.5% versus 17.8%; P < 0.001). The proportion of infants feeding exclusively orally at hospital discharge differed significantly, from most to least: MDO, TLA, and tracheostomy. Hospital length of stay was not statistically different for patients who had MDO or TLA, but was longer for those with primary tracheostomy. The mortality rate was low for all operations (0.5%). Conclusions: In this surgical patient cohort, MDO was associated with shorter hospital stay, improved oral feeding, and lower rates of secondary airway operations. Prospective multicenter studies are necessary to support these conclusions.