The reliability of lamellar body count in predicting absence of respiratory distress syndrome from transvaginal and transabdominal amniotic fluid samples

Abstract

THE EXPECTED CHANGE OVER TIME? SHAD DEERING, SARAH POGGI, CATHERINE SPONG, FRANCA BARTON, KATIE GOODWIN, ALESSANDRO GHIDINI, Georgetown University, Obstetrics and Gynecology, Washington, DC Georgetown University, Biostatistics, Washington, DC OBJECTIVE: To assess the change in the lamellar body count (LBC) in patients undergoing repeat testing for fetal lung maturity to see if a predictable change in LBC over a given period of time exists. STUDY DESIGN: We analyzed a cohort of women from 1998 to 2003 at a single institution who underwent amniotic fluid sampling at least twice during pregnancy for determination of fetal lung maturity. Charts were reviewed and maternal demographic information, as well as data regarding the gestational age at sampling and the LBC, were recorded. This study was approved by the institutional review board. Statistical analysis included linear regression of LBC and gestational age. RESULTS: There were a total of 24 patients who had at least two samples taken during the study period for a total of 57 samples. Themean gestational age at sampling was 34.8 ± 0.3 weeks. Linear regression demonstrated that the LBC count increased by 5087 per week (P = 0.008). This increase did not change significantly with increasing gestational age. CONCLUSION: The LBC count increases approximately 5100 per week during pregnancy after 28 weeks’ gestation and the rise appears to be consistent and linear. This information may be beneficial in determining when a patient can be expected to have a level consistent with fetal lung maturity after a given LBC and therefore have a low risk of RDS.