The most appropriate time for the nurse to encourage a laboring woman to push is during

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. Accelerations are normal responses that indicate the fetus is healthy and active. Accelerations occur when the fetal heart rate increases in response to stimuli. •

Choice B. Late decelerations are nonreassuring patterns that indicate fetal hypoxia due to placental insufficiency. Late decelerations occur when the placental blood flow decreases due to uterine contractions during labor, causing the fetal heart rate to decrease. •

Choice C. Variable decelerations are nonreassuring patterns that indicate fetal hypoxia due to umbilical cord compression. Variable decelerations occur when the umbilical cord is trapped by the cervical opening or the fetal body part, twisted, or knotted, causing the fetal oxygen supply to be impaired and the fetal heart rate to drop sharply. •

Choice D. Early decelerations are reassuring patterns that indicate a neural reflex due to fetal head compression. Early decelerations occur when the fetal head is compressed by uterine contractions during labor, causing the parasympathetic nervous system to be stimulated and the heart rate to decrease. The correct answer is C. Variable decelerations are the most common pattern that indicates a problem with the umbilical cord and requires urgent intervention.