The nurse notices while holding him upright that a 1-day-old newborn has a significantly indented anterior fontanelle. She immediately brings it to the attention of the physician. What does this finding most likely indicate?

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.

Choice A reason:

Basal metabolic rate reduction. This is incorrect because a newborn under a radiant heat warmer will have an increased basal metabolic rate, not a reduced one. The basal metabolic rate is the amount of energy the body uses at rest, and it is influenced by temperature. A warmer environment will stimulate the newborn's metabolism and increase the energy expenditure. • Choice B reason:

Brown fat production. This is incorrect because a newborn under a radiant heat warmer will have less need for brown fat production, not more. Brown fat is a type of fat tissue that generates heat by burning calories. It is found in newborns and helps them maintain their body temperature in cold environments. A warmer environment will reduce the need for brown fat activation. • Choice C reason:

Shivering. This is incorrect because a newborn under a radiant heat warmer will not shiver, but shivering is not the main mechanism of heat production in newborns. Shivering is an involuntary contraction of muscles that generates heat by increasing metabolism. Newborns have limited ability to shiver because of their immature nervous system and low muscle mass. They rely more on brown fat and increased metabolic rate to produce heat. • Choice D reason:

Cold stress. This is correct because a newborn under a radiant heat warmer will prevent cold stress, which is a condition where the newborn's body temperature drops below normal and causes adverse effects. Cold stress can impair oxygen delivery, increase acidosis, decrease blood glucose, and increase the risk of infection and bleeding. A radiant heat warmer provides a neutral thermal environment for the newborn and prevents heat loss by radiation.

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