A nurse is assisting in the care of a client who is scheduled for a cesarean birth based on the fetal lungs having reached maturity. Which of the following findings indicates that the fetal lungs are mature?

Choice A rationale: Applying ice to the perineal area is not indicated in the case of suspected placenta previa. Placenta previa is related to the location of the placenta in the uterus and is not affected by the perineal area. Ice is commonly used for perineal discomfort after vaginal delivery but is not appropriate for placenta previa.
Choice B rationale: When a client is suspected to have placenta previa, a vaginal exam should be avoided because it can cause trauma to the placenta, leading to significant bleeding. Placenta previa is a condition where the placenta covers part or all of the cervix, and any disruption of the placenta can result in bleeding, which poses a risk to both the mother and the baby. Therefore, a vaginal exam is contraindicated in this situation.
Choice C rationale: Performing a rectal exam is also not appropriate for a client with suspected placenta previa. Rectal exams do not provide any relevant information about the placenta's location, and they can potentially cause discomfort or bleeding in this situation.
Choice D rationale: Applying an external fetal monitor is an appropriate action when caring for a pregnant client, regardless of whether there is a suspected placenta previa. The external fetal monitor is used to assess the baby's heart rate and uterine contractions and is a routine part of prenatal care. However, it does not specifically address the issue of placenta previa. The nurse should be vigilant for any signs of bleeding or changes in fetal heart rate pattern, which may indicate placental issues, and report them promptly for further evaluation and management.

Choice A rationale: The presence of phosphatidylglycerol (PG) in the amniotic fluid is another indicator of fetal lung maturity. The absence of PG is associated with an increased risk of respiratory distress syndrome (RDS) in the newborn.
Choice B rationale: A nonstress test is a test performed during pregnancy to evaluate the fetal heart rate in response to fetal movement. It is not directly related to assessing fetal lung maturity.
Choice C rationale: The L/S ratio is an important indicator of fetal lung maturity. Lecithin and sphingomyelin are two surfactants present in the lungs, and the ratio of these two substances increases as the fetal lungs mature. An L/S ratio of 2:1 or greater is considered an indication of lung maturity and suggests that the newborn should be able to breathe adequately after birth.
Choice D rationale: The biophysical profile (BPP) is a prenatal ultrasound assessment of the fetus, which includes evaluating fetal movements, breathing, heart rate, and amniotic fluid volume. While a BPP of 8 is a reassuring score, it does not provide direct information about fetal lung maturity.