Final answer:
To determine fetal maturity, the Lecithin/sphingomyelin (L/S) ratio is measured in the amniotic fluid, with a healthy mature fetus typically reflecting a ratio of approximately 2:1.
Step-by-step explanation:
Amniotic fluid is analyzed to assess fetal maturity, and the specific component measured for determining this is the Lecithin/sphingomyelin (L/S) ratio. For a mature fetus, the L/S ratio is approximately 2:1, where a ratio greater than this suggests mature lung development, indicative of good fetal maturity and decreased risk of infant respiratory distress syndrome. The lecithin to sphingomyelin ratio in mature fetal lungs is approximately 2.5. If the ratio falls between 2.4 and 1.6, it suggests a low risk, while a ratio less than 1.5 indicates a higher risk and potential need for clinical intervention.
Other substances in amniotic fluid like Alpha-fetoprotein (AFP) and Human chorionic gonadotropin (hCG), and metrics like the Amniotic fluid index (AFI), also provide valuable information about fetal health but are not specifically used to measure fetal lung maturity. For instance, AFP is often measured to assess the risk of genetic and developmental abnormalities, while AFI is used to measure the amount of amniotic fluid present which reflects the well-being of the fetus.