Humans are homotherms; capable of maintaining body temperature at a relatively constant level despite changes in the external environment. The ability of infants to regulate temperature in response to thermal stress is limited. Infants are unable to sweat in order to give off excessive heat when they become overheated. The infant is capable of heat production through three mechanisms 1) voluntary muscle activity, 2) involuntary muscle activity, and 3) metabolism. Voluntary and involuntary muscle activity is limited and requires a chemical reaction utilizing large stores of energy. Term infants are capable of assuming a flexed position when cool and an extended position when overheated. The ability is limited in the premature infant, though it may be present to some extent. Non-shivering thermo genesis appears to be the most consistent method of heat production in the neonate regardless of gestational age or birth weight. The major source of heat energy in the newborn is fatty acids. Thermo genesis is directly dependent on tissue oxygenation to utilize heat energy. Oxidized fatty acids generally are believed to derive from brown fat stores in the neonate. Brown fat has high vascularization and is virtually nonexistent in preterm infants. Term infants have approximately 16 percent of body tissue mass as adipose tissue, but the preterm infant may have as little as 3.5 percent adipose tissue per body weight. Brown fat is located around the mediastinal structures, kidneys, scapulas, axilla and nape of the neck. Primitive brown cells first appear at 26-30 weeks gestation and ordinarily disappear by three to five weeks after birth. Upon exposure to cold, thermal receptors in the skin (many of which are located in the face) signal the neonate’s central hypothalamus resulting in sympathetic nervous system arousal and the release of norepinephrine. The release of norepinephrine then stimulates the hydrolysis or breakdown of the brown fat. The rapid metabolism of brown fat produces heat, which warms the blood perfusing surrounding tissue. This heat is then transferred via the circulation to the rest of the body. This process consumes a lot of oxygen and glucose. Asphyxia and hypoxia further compromise the infant’s ability to generate heat. Utilizing energy to produce heat requires an increase in oxygen consumption. In the hypoxic state, two molecules of adenosine triphosphate (ATP) are generated from a molecule of glucose instead of 38 molecules of ATP generated in the normally oxygenated infant. In order to produce heat energy in the hypoxic state, greater glucose stores must be utilized. Without sufficient oxygenation, asphyxiated or hypoxic infants have a decreased ability to generate heat. When the infant with already limited resources for heat production encounters environmental changes that threaten his ability to maintain an adequate temperature, a serious condition exists. The metabolic rate gradually increases during the first week of life. Heat production also improves during the first few days of life with the institution of feedings. It is not clear why heat is produced. It may be due to increased metabolism during digestion, or it may be that heat can be generated when sufficient energy is provided via ingestion. Ingestion of human milk has been found to increase metabolism in low birth weight infants, leading to production of heat. Thermoregulatory needs gradually change as the infant grows, matures and feeds. Skip to content
When a healthy baby has a low temperature, it may not signal a problem. However, very low temperatures may indicate or cause a serious health problem. The average healthy body temperature is 98.6°F. Shifts in a baby’s activity level or environment can affect their temperature, while different methods of taking a temperature can give slightly different readings. Newborns and babies are less able to regulate their body temperature. Because of this, when a baby has a low temperature, it is important to address the cause quickly. A variety of factors can cause a low temperature in a baby. They include:
The most common reason for low body temperature is that babies, especially newborns, cannot regulate their body temperature as well as older children and adults. So exposure to even slightly low temperatures is more likely to cause a low body temperature in a newborn. It is also important to note that taking temperatures incorrectly or using inaccurate equipment may give incorrect readings. Using a variety of methods or thermometers may address inaccuracies. Share on PinterestA rectum temperature reading usually provides the most accurate information. The ideal baby temperature depends on the method a person uses to take the temperature. In babies younger than 2 years old, rectum temperature readings offer the most accurate information, provided the parent or caregiver takes the measurement correctly, using working equipment. Healthy temperature readings are as follows:
Temperatures below these ranges may signal hypothermia, which is a dangerously low body temperature. Temperatures above these ranges could be a sign of a fever. A fever may mean the baby has an infection or is too hot. Each baby is different. Sometimes a falling temperature indicates a problem even if the baby’s temperature is within the normal range. So ask a healthcare provider about the ideal temperature for the baby. The World Health Organization (WHO) recommend measuring a very unwell baby’s temperature as frequently as hourly. In a very small baby, taking the temperature two to four times daily can help with detecting unhealthy temperature swings. The WHO advise taking daily temperature readings in an infant whose condition is improving. The correct treatment depends on why the baby’s temperature is low. Babies are vulnerable both to cold and to overheating. Because of this, parents or caregivers should not overdress babies, put them in front of hot radiators, or otherwise expose them to intense heat in an attempt to warm them. It is important to see a healthcare provider if a baby has a low temperature that does not rise after using strategies such as dressing the baby more warmly or increasing the temperature of the house. When a newborn has trouble regulating their body temperature, some strategies can help. They include:
If these strategies fail, a healthcare provider may recommend:
Dressing a baby in seasonally appropriate clothing—without overdressing or overheating the baby—can prevent them from getting too cold. Skin-to-skin contact with a parent or caregiver is also helpful because their warm body may help regulate the baby’s body temperature. However, it is not possible to prevent all cases of hypothermia or low body temperature. Sometimes, a low body temperature indicates that the baby’s brain is not sending the right signals to regulate its body temperature or that the baby’s body cannot do certain things that would generally raise body temperature. Seeking prompt medical care when a baby has a body temperature more than a degree below normal can help prevent serious complications. Share on PinterestParents and caregivers should talk to a doctor if their baby has an abnormal temperature. Infections are more dangerous in young infants. Babies and newborns are also less able to regulate their body temperature. Parents or caregivers should err on the side of caution when a baby has an abnormal temperature, especially if the baby was born prematurely or is younger than 3 months old. Call a doctor anytime a baby’s temperature falls outside the normal range. Seek emergency care if a baby seems lethargic or their temperature continues falling despite efforts to warm them. Parents of low birth weight and premature babies should ask a healthcare provider when to seek emergency care for a low temperature. It is important to take changes in temperature seriously, particularly if the baby has other health risk factors, such as an infection, a history of breathing problems, or they were born prematurely. However, a low body temperature is not a reason to panic, especially if the temperature is just a few tenths of a point outside the normal range. A pediatrician or other healthcare provider can help parents or caregivers decide if the low temperature is normal and healthy, or a sign of a problem. Seek treatment as soon as possible, since a healthcare provider can offer peace of mind and ensure the baby gets the right treatment. |