The student nurse learns that the hormone necessary for milk production is

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:

A prolapsed umbilical cord occurs when the cord slips ahead of the presenting fetal part, potentially leading to cord compression and compromised fetal oxygenation. However, hypertonic contractions do not directly cause a prolapsed cord. Instead, factors such as premature rupture of membranes, abnormal fetal positioning, or excessive amniotic fluid (polyhydramnios) are more likely contributors to cord prolapse. Hypertonic contractions primarily affect uteroplacental circulation rather than fetal positioning.

Choice B reason:

One side effect of oxytocin stimulation is hypertonic contractions. This can be detrimental to the fetus because it produces a prolapsed cord. This is incorrect because a prolapsed cord is not caused by hypertonic contractions, but by other factors such as a low-lying placenta, a premature rupture of membranes, a small or preterm fetus, or an abnormal presentation. A prolapsed cord occurs when the umbilical cord slips through the cervix and into the vagina before or during delivery. This can compress the cord and cut off the blood supply to the fetus, resulting in fetal bradycardia and possible death.

Choice C reason:

One side effect of oxytocin stimulation is hypertonic contractions. This can be detrimental to the fetus because it increases maternal renal blood flow. This is incorrect because hypertonic contractions do not affect maternal renal blood flow directly. Maternal renal blood flow is influenced by factors such as maternal blood pressure, hydration, cardiac output, and renal function. Hypertonic contractions may cause maternal dehydration, which can reduce renal blood flow, but this is not a direct effect of oxytocin stimulation.

Choice D reason:

Hypertonic contractions reduce placental blood flow by limiting the relaxation phase between contractions. Normally, uterine contractions intermittently compress the spiral arteries supplying the placenta, but prolonged or excessively frequent contractions prevent adequate placental perfusion. This can lead to fetal hypoxia, acidosis, and distress, making it the most detrimental effect of oxytocin-induced hypertonic contractions.