Amniotic fluid analysis

Neonatal respiratory distress syndrome (also known as hyaline membrane disease) is a major cause of death in premature infants and is the result of inadequate surfactant production in the lungs. Which of the following can be used to determine the maturity of fetal lungs in utero?

Amniotic fluid analysis
Chorionic villus sampling
Fetal heart rate monitor
Karyotype analysis

Correct answer
Amniotic fluid analysis
correct answer: A

Amniotic fluid can be analyzed to determine the lecithin to sphingomyelin ratio. A ratio > 2 is rarely associated with Neonatal respiratory distress syndrome (NRDS). In NRDS the ratio is usually < 1.5.
The other tests are not the test of choice for determining fetal lung maturity.