Intra-amniotic infection increases amniotic lamellar body count before 34 weeks of gestation

To examine the lamellar body count (LBC) value in intra-amniotic infection cases and evaluate its association with the incidence of respiratory distress syndrome (RDS).

Three hundred sixty-five amniotic fluid (AF) samples were obtained at caesarean section from 27 to 38 weeks of gestation. LBC and glucose concentrations in AF were measured with no centrifugation. We defined AF glucose concentrations<0.8 mmol/L and positive C-reactive protein (CRP) of the neonates as intra-amniotic infection.

An LBC cutoff value of 29,500/μL resulted in 94.0% sensitivity, 82.4% specificity, and 99.1% negative predictive value (NPV) for RDS. Neonates with glucose concentrations<0.8 mmol/L in AF and positive CRP had no RDS and significantly higher LBC values than controls before 34 weeks of gestation (17.0 vs. 4.3, p<0.05 and 25.5 vs. 5.0, p<0.05, respectively), but there were no significant differences after 34 weeks of gestation.

LBC is an accurate predictor of foetal lung maturity and our LBC cutoff value had a high NPV for predicting RDS. We showed that intra-amniotic infection was associated with significantly higher LBC values than the value in controls before 34 weeks of gestation, which correlated with a low incidence of RDS.