The nurse is aware that the Tanner staging system for sexual maturity is:

A. Alertness as such weight loss is not expected: This response may unnecessarily alarm the mother when, in fact, some weight loss in the early days is normal.

B. Reassurance as this is a normal weight loss.

It is normal for newborns to lose some weight during the first few days of life. The loss is often related to fluid loss, changes in feeding patterns, and initial adjustment to life outside the womb. A loss of one-half pound in a 2-day-old neonate is generally considered within the normal range. It's important for the nurse to reassure the new mother that this weight loss is expected and not a cause for alarm. Newborns typically start to regain their birth weight within a week or two. This reassurance can help ease the mother's distress and anxiety.

C. Alarm as this is a drastic weight loss: Characterizing this weight loss as "drastic" is not accurate or helpful and would likely increase the mother's anxiety.

D. Concern as this may be an indicator of inadequate nutrition: Jumping to the conclusion of inadequate nutrition without further assessment and evidence is premature and may unnecessarily worry the mother. It's important to start with reassurance and then investigate if there are concerns about nutrition.

A. Rigid abdomen: A rigid abdomen is not a common finding in HPS. However, it is more typical in conditions such as intestinal obstruction.

B. Distended neck veins: Distended neck veins are not a typical manifestation of HPS. They may be associated with other cardiovascular or respiratory issues.

C. Red currant jelly stools: Red currant jelly-like stools are not typically seen in HPS. This description is often used to describe the appearance of stools in intussusception, which is a different gastrointestinal condition.

D. Projectile vomiting.

Hypertrophic pyloric stenosis is a condition in infants where the muscle at the outlet of the stomach (pylorus) becomes thickened and obstructs the passage of food from the stomach into the small intestine. Projectile vomiting is a characteristic symptom of HPS. The vomit is forceful and seems to shoot out of the infant's mouth, typically occurring after feeding.