North American Registry of Midwives (NARM) Practice Exam

What triggers non-shivering thermogenesis in newborns?

1. The presence of food

2. A cold stimulus

3. Physical activity

4. External heating sources

The correct answer is: A cold stimulus

Non-shivering thermogenesis in newborns is primarily triggered by a cold stimulus. This physiological response is crucial for maintaining body temperature in infants who have limited ability to generate heat through muscle contractions, as they do not have well-developed shivering mechanisms at birth. Instead, newborns rely on brown adipose tissue, which can generate heat without shivering when exposed to cold conditions. This process helps protect vulnerable newborns from hypothermia and is essential for their overall metabolic stability. While the other options may influence thermoregulation in different ways, they do not directly initiate non-shivering thermogenesis. Food consumption primarily contributes to energy availability but is not a direct trigger for heat production through non-shivering mechanisms. Physical activity also does not play a significant role in newborns due to their limited physical capability. External heating sources are instead utilized to prevent hypothermia, but they do not provoke the physiological response of non-shivering thermogenesis. Hence, the link between cold stimuli and the activation of brown adipose tissue underscores why a cold stimulus is the correct answer.