Which indicator is the most reliable for assessing lung maturity, even in mothers with diabetes?

The most reliable indicator for assessing lung maturity, especially in the context of mothers with diabetes, is phosphatidylglycerol (PG). This lipid is a crucial component of the pulmonary surfactant that helps reduce surface tension in the alveoli, thus facilitating proper lung function and preventing atelectasis.

In cases where a mother has diabetes, fetal lung maturity can be delayed, and traditional assessments of lung maturity may not be as reliable. PG levels in amniotic fluid serve as a more specific marker than other phospholipids such as phosphatidylcholine (PC), which is another major component of surfactant but may not provide as definitive an indication of lung maturity on its own.

Monitoring PG levels allows healthcare providers to better predict the readiness of the infant's lungs for breathing air, especially important in complications caused by maternal diabetes, where surfactant production may be altered. Thus, PG is critical for assessing the readiness of the infant's lungs to function effectively outside the womb.