respiratory system disorder pulmonary hypoplasia https://github.com/monarch-initiative/mondo/issues/5261 https://github.com/monarch-initiative/mondo/issues/6754 A respiratory malformation characterized by the presence of both bronchi (albeit rudimentary) and alveoli in an under-developed lobe. Both the size and the weight of the lung are reduced. The true prevalence is not well known (1.4% of all births according to Knox et al. 13), but in cases of premature rupture of membranes at 15-28 weeks gestation, the reported prevalence of pulmonary hypoplasia ranges from 9 to 28%. Factors that contribute to pulmonary hypoplasia include adequate volume of the thoracic cavity, pulmonary fluid dynamics, and abnormal fetal breathing movements. GARD:0026450 MEDGEN:78574 MONDO:0800133 NCIT:C99035 UMLS:C0265783