Clinical Analysis of Lamellar Body Count and L/S ratio in Amniotic Fluid as a Screening Test for Fetal Lung Maturity

Yoon, Seong Jun

Abstract

OBJECTIVES
Predicting maturity of the fetal lung is important in many obstetric situations. Lamellar bodies are synthesized and secreted by the type II pneumocytes of fetal lung. The phospholipids present in these bodies constitute the major component of pulmonary surfactant. The purpose of this study was to evaluate the usefulness of lamellar body count in amniotic fluid as a rapid fetal lung maturity screening test and to determine the cutoff value of lamellar body count that will indicate fetal lung maturity
METHODS
From October 1998 to July 2000, 60 patients who delivered before 39 weeks gestation at the Chung-Ang University Hospital were tested for lamellar body count in the amniotic fluid. Indications for assessment of fetal lung maturity included preterm labor, premature rupture of membranes, previous cesarean section, pregnancy-induced hypertension and others.
RESULTS
1. The prevalence of RDS in the study population was 15%(9 of 60 cases). 2. The mean lamellar body count and L/S ratio for RDS group were much less than that of non-RDS group(14000 vs 47470, p<0.01 and 1.3 vs 2.5, p<0.01). 3. There was a good linear correlation between lamellar body count and L/S ratio(r=0.86, p<0.01), as did between lamellar body count and gestational age(r=0.679, p<0.01). 4. In the critical function of predicting fetal lung maturity, our data demonstrate that when using a cutoff of 25000/microliter, the lamellar body count showed 88.8% sensitivity, 96.0% specificity, 80.0% positive predictive value, 98.0% negative predictive value, respectively.
CONCLUSION
This study, along with those reported previously, confirms that lamellar body count reflects fetal lung maturity sufficiently to assure that the neonate will not develop respiratory distress syndrome. Further evaluation for this purpose is justified.