The ways of amniotic fluid sampling and its influence on lamellar body count

Even though artificial surfactant is now available, respiratory distress syndrome still remains a serious problem in neonatology. Prenatal analysis of the amniotic fluid can provide data giving insight into the fetal lung maturity, which enables planning of the further outcome of high-risk pregnancies. Surfactant prevents atelectasis by forming a layer rich in phospholipids between the air and liquid phase in alveoli thus leading to increased surface tension in them, which is a precondition for a good lung function after birth. Lamellar bodies are a form of stored surfactant, and their count in the amniotic fluid can be determined simply by a standard hematology analyzer. The method of determining lamellar body count has found an important place in prenatal diagnostics and is recommended as an initial method of a "cascade" procedure of testing fetal lung maturity. However, considering the importance of procedure of sample collection, storage and centrifugation, which can significantly affect the results obtained for the lung maturity, the amniotic fluid samples must be absolutely free of contamination with blood, meconium, mucus, bacteria and leucocytes.