Objective: Pulmonary hypoplasia (PH) is one of the commonest causes of neonatal morbidity and mortality. The suggested diagnostic criteria for PH are the Lung Weight:Body Weight (LW:BW) ratio ≤ 0.012 and/or Radial Alveolar Count (RAC) ≤ 4.1. The present study was done to determine the relative frequency of PH in fetal autopsy study by the LW:BW ratio and RAC along with evaluation of the defects/anomalies associated with PH.

Material and Method: A prospective observational study was done on fetal autopsy specimens in the Department of Pathology. Examination and grossing were done as per the standard format of fetal autopsy study. Evaluation of PH was done using the LW:BW ratio and RAC. Diagnostic criteria for PH were taken as LW:BW ratio <0.012 and/ or RAC < 4.1. Chi-square test, Student T test and Kruskal Wallis test were used in statistical analysis.

Results: A diagnosis of PH was made in 45 cases. Concordance between the LW:BW ratio and RAC was observed in 33 cases amounting to 73.33%. The mean LW:BW ratio was the lowest in oligohydramnios. The mean RAC was the lowest in congenital cystic adenomatoid malformation.

Conclusion: A diagnosis of PH was rendered in a greater number of cases when evaluation was done by considering both the LW:BW ratio and RAC. Hence, evaluation by both the LW:BW ratio and RAC provides a reliable index of lung growth and should be an essential part of fetal autopsy study.