A nurse is teaching a client who is scheduled for an amniocentesis about the purpose of a lecithin/sphingomyelin ratio test.
Which of the following statements should the nurse make?

Choice A rationale

The lecithin/sphingomyelin (L/S) ratio test is a crucial assessment of fetal lung maturity. Lecithin and sphingomyelin are phospholipids that are components of surfactant, a substance vital for reducing surface tension in the alveoli and preventing lung collapse at birth. A ratio of 2: or greater generally indicates adequate lung maturity.

Choice B rationale

The L/S ratio test does not assess the baby's blood type. Fetal blood typing is determined through other methods, such as cordocentesis or maternal blood tests for fetal DNA, if clinically indicated. The L/S ratio specifically evaluates the quantity and ratio of pulmonary surfactants.

Choice C rationale

This test does not check the baby's liver development. Fetal liver development is assessed through different parameters, such as ultrasound visualization of liver size, blood flow characteristics, and specific liver enzyme levels if a concern exists. The L/S ratio is solely focused on pulmonary maturity.

Choice D rationale

The L/S ratio test is not used to check for genetic disorders. Genetic disorders are identified through chromosomal analysis, DNA sequencing, or biochemical tests performed on amniotic fluid cells obtained during amniocentesis, or through chorionic villus sampling. The L/S ratio is a physiological marker of lung readiness.

Choice A rationale

A prolonged period of absent FHR variability is a critical finding that the nurse must report to the provider immediately. Absent variability indicates a significant lack of fetal well-being, potentially due to severe hypoxia, acidosis, or neurological compromise. It necessitates prompt intervention to prevent adverse outcomes.

Choice B rationale

An FHR increase to 150/min is within the normal fetal heart rate range, which typically falls between 110 and 160 beats per minute. This finding alone does not indicate a problem and would not require reporting to the provider, as it suggests adequate fetal oxygenation and an appropriately reactive fetus.

Choice C rationale

FHR accelerations of 15/min for 15 seconds are a positive sign of fetal well-being. Accelerations indicate an intact fetal nervous system and adequate oxygenation. They are a reassuring finding and suggest that the fetus is tolerating the labor process well, therefore not requiring reporting.

Choice D rationale

Early decelerations of the FHR are typically benign and do not require reporting to the provider. These decelerations are usually associated with head compression during contractions and are characterized by a gradual decrease in FHR that mirrors the contraction, indicating a physiological response.