Assessment of fetal lung maturity. Practice parameter

Area of Science:

• Obstetrics and Gynecology
• Neonatology
• Clinical Chemistry

Background:

• Respiratory distress syndrome (RDS) persists as a significant clinical challenge despite advancements in artificial surfactant and respiratory support.
• Accurate assessment of fetal lung maturity (FLM) is essential due to the low prevalence of RDS, necessitating highly sensitive and specific diagnostic methods.
• Current FLM testing methods often involve complex instrumentation, skilled personnel, and extended analysis times.

Purpose of the Study:

• To evaluate the utility of widely available methods for assessing fetal lung maturity.
• To provide a practice parameter for laboratory assessment of FLM.
• To streamline FLM testing protocols while maintaining diagnostic accuracy.

Main Methods:

• Review of existing practice parameters and laboratory methods for FLM assessment.
• Discussion of the essential role of satisfactory amniotic fluid specimens.
• Evaluation of specific tests including lecithin/sphingomyelin (L/S) ratio, phosphatidylglycerol (PG), fluorescence polarization, and lamellar body number density.

Main Results:

• A satisfactory amniotic fluid specimen is critical for reliable FLM assessment.
• No single test is entirely free from analytical interferences.
• Lecithin/sphingomyelin (L/S) ratio and thin-layer chromatography for phosphatidylglycerol (PG) are deemed unnecessary as obligatory components of FLM testing panels.
• Fluorescence polarization or lamellar body number density serve as acceptable initial screening tests for FLM.
• Sequential rapid testing, including PG assessment (Amniostat-FLM), can resolve borderline or immature results.
• In cases of poorly controlled diabetes, PG assessment is recommended to mitigate false maturity predictions from other rapid tests.

Conclusions:

• Fluorescence polarization or lamellar body number density are recommended as initial screening tests for FLM.
• Additional rapid testing can be employed for borderline or immature results.
• Phosphatidylglycerol (PG) assessment is crucial in specific scenarios, such as poorly controlled diabetes, to ensure accurate FLM prediction.
• Clinical judgment remains the paramount factor in decisions regarding fetal delivery.