The nurse completes the initial assessment of a newborn. Which finding would lead the nurse to suspect that the newborn is experiencing difficulty with oxygenation?

The correct answer is choice B. Prolactin.

Choice A reason:

Estrogen. Estrogen is a hormone that plays a role in the development of the mammary glands and the ductal system during pregnancy. However, estrogen does not directly produce milk.

In fact, high levels of estrogen during pregnancy inhibit milk secretion by blocking prolactin. Therefore, estrogen is not the hormone necessary for milk production. • Choice B reason:

Prolactin. Prolactin is the hormone responsible for the production of breast milk. Prolactin is secreted by the pituitary gland in response to suckling or nipple stimulation. Prolactin levels rise during pregnancy and peak after delivery, when the sudden drop in estrogen and progesterone allows prolactin to take over and initiate lactation. Therefore, prolactin is the hormone necessary for milk production. • Choice C reason:

Progesterone. Progesterone is a hormone that also contributes to the development of the mammary glands and the alveoli during pregnancy. However, like estrogen, progesterone does not directly produce milk. Progesterone also inhibits milk secretion by blocking prolactin during pregnancy. Therefore, progesterone is not the hormone necessary for milk production. •

Choice D reason:

Lactogen. Lactogen is not a hormone, but a general term for any substance that stimulates lactation. There are different types of lactogens, such as human placental lactogen (hPL), which is produced by the placenta during pregnancy and has some lactogenic effects on the mammary glands. However, hPL is not the main hormone responsible for milk production. That role belongs to prolactin. Therefore, lactogen is not the hormone necessary for milk production.

Choice A reason:

Acrocyanosis (choice A) is a common and relatively normal finding in newborns, especially in the first few days of life. It refers to the bluish discoloration of the hands and feet due to peripheral vasoconstriction. Acrocyanosis alone does not necessarily indicate significant difficulty with oxygenation and is usually a transient and benign condition.

Choice B reason:

A respiratory rate of 54 breaths/minute (choice B) is within the normal range for a newborn. The normal respiratory rate for a newborn can range from 30 to 60 breaths per minute. While an abnormal respiratory rate outside this range may be a concern, a rate of 54 breaths/minute is not indicative of significant oxygenation difficulty by itself.

Choice C reason:

Nasal flaring in a newborn is a concerning sign that suggests the baby is experiencing difficulty with oxygenation. When a newborn is having trouble getting enough oxygen, they may instinctively open their nostrils wider (nasal flaring) to increase the airflow into the nose and improve oxygen intake. This is a compensatory mechanism to overcome respiratory distress and is often seen in newborns with respiratory problems. Nasal flaring is an important clinical sign that indicates the baby may be struggling to breathe adequately and requires further evaluation and intervention by the healthcare team.

Choice D reason:

Abdominal breathing (choice D) is a normal breathing pattern in newborns. Newborns predominantly use their diaphragm to breathe, which results in abdominal movements during respiration. This is a normal and expected finding in healthy newborns and does not necessarily suggest oxygenation problems.