A nurse is caring for a newborn whose mother is positive for the hepatitis B surface antigen. Which of the following treatments should the infant receive?

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.

Choice A rationale: The Mongolian spot is a bluish-gray birthmark that is often seen on the lower back or buttocks of newborns with darker skin tones. It is not related to the swelling described in the scenario.
Choice B rationale: Caput succedaneum is a common condition in newborns delivered by vacuum extraction. It is characterized by swelling of the soft tissues of the scalp that crosses the suture lines. The swelling occurs due to pressure from the vacuum extractor during delivery and is caused by fluid accumulation between the scalp and the skull. Caput succedaneum is typically a benign and self-resolving condition that does not require treatment.
Choice C rationale: Cephalhematoma is a collection of blood between the periosteum and the skull bone. Unlike caput succedaneum, it does not cross the suture lines and can take weeks to months to resolve.
Choice D rationale: Erythema toxicum is a common skin rash in newborns characterized by red or pink spots with a yellow or white bump in the center. It is not related to the swelling described in the scenario.