Objectives: To design a predictive model for assessing the risk of developing respiratory distress syndrome (RDS) using gestational age (GA) and lamellar body counts (LBC). Design and methods: LBCs and patient outcome data was obtained from five medical centers. A total of 223 patients were included in this study; 19 gave birth to infants that developed RDS, 204 gave birth to infants that were unaffected. The absolute risk and odds ratios of an infant developing RDS as a function of GA and LBC were calculated. Logistic analysis was used to model the odds of RDS as a function of GA and LBC. Results: The odds of RDS decreased for each increasing week of GA and decreased with increase in the LBC. GA-specific LBC cutoffs are provided for sensitivities between 84 and 100%. The bias adjusted area under the ROC curve for the classification of RDS, based on GA and LBC, was 0.906 using the logistic model and 0.746 using a single cutoff of LBC (50,000/μL) to classify immaturity. Conclusions: GA-specific risk assessment and GA-specific cutoffs provide increased sensitivity and specificity in the evaluation of fetal lung maturity.
- Fetal lung maturity
- Gestational age
- Lamellar body count
- Respiratory distress syndrome