A client is concerned about their newborn's risk for respiratory distress.

The nurse explains that the highest risk for respiratory distress is seen in:.

Preterm infants are at the highest risk for respiratory distress syndrome (RDS), a common breathing disorder that affects newborns.RDS occurs because of a lack of surfactant, a foamy substance that keeps the lungs fully expanded.Surfactant is usually produced by the lungs during the third trimester of pregnancy, which starts after the 26th week.Therefore, babies born before their due date, especially before 28 weeks of pregnancy, are more likely to have RDS.

Choice B is wrong because macrosomic babies, or babies who are larger than average at birth, are not at increased risk for RDS.

However, they may have other complications such as birth injuries or low blood sugar levels.

Choice C is wrong because post-term infants, or babies who are born after 42 weeks of pregnancy, are not at increased risk for RDS.

However, they may have other complications such as meconium aspiration or low blood sugar levels.

Choice D is wrong because newborns with hyperbilirubinemia, or high levels of bilirubin in the blood, are not at increased risk for RDS.

However, they may have other complications such as jaundice or brain damage.

Other risk factors for RDS include being a white male, having multiple fetuses, having a mother with diabetes, and having premature rupture of membranes (PROM).

The correct answer is choice B. Pathologic jaundice.Pathologic jaundice is a type of jaundice that occurs due to an underlying health problem, such as blood group incompatibility, infection, liver disease, or enzyme deficiency.

Pathologic jaundice usually appears within the first 24 hours of life and can cause severe complications if not treated promptly.

Choice A is wrong because physiologic jaundice is a normal and common condition that occurs in most newborns due to the immaturity of their liver and the high turnover of red blood cells.Physiologic jaundice usually appears between the second and fourth day after birth and resolves within one to two weeks without treatment.

Choice C is wrong because hypoglycemia is a low blood sugar level that can cause symptoms such as jitteriness, poor feeding, lethargy, and seizures in newborns.Hypoglycemia is not directly related to bilirubin levels or jaundice, although some conditions that cause hypoglycemia, such as prematurity or infection, can also increase the risk of jaundice.

Choice D is wrong because preterm birth is a risk factor for jaundice, not a cause of it.Preterm babies have higher bilirubin levels because their liver is less developed and their red blood cells have a shorter lifespan than term babies.

Preterm birth can also be associated with other causes of pathologic jaundice, such as infection or hemolysis (breakdown of red blood cells)