Newborn Baby Temperature

Newborn baby is unable to control body heat as efficiently as an older child.
External changes in temperature can vary a baby's body temperature considerably.
Unless a baby is kept adequately warm, he or she could suffer from hypothermia.
This does not mean that the parents must constantly check the baby's temperature with a thermometer, but they must be aware of potentially dangerous situations.

A baby's bedroom must be maintained at a temperature of at least 65°F (18.3°C).
The room should be kept slightly warmer for babies under 8 pounds (3.6 kg).
A thermostat heater is an efficient method of keeping the room warm throughout the night.
During the winter, warm the baby's crib with a hot water bottle before placing him or her in it, but remember to remove the bottle first.
Never use an electric blanket on a baby's bed.
Also, before putting the baby to bed, cuddle him or her. A tiny baby does not move much during the night and is unlikely to warm up. A cuddle before bed warms the baby.
During hot summer weather a baby should wear light, loosely fitting, cool clothing.
As long as he or she is protected from direct sun, the baby can lie outside in nothing but a diaper.
Overdressing, causing overheating, is one of the most common reasons for irritable babies during the summer.
Never leave a small baby or child unattended in a car. 
This is especially important during the summer, especially if the car is in direct sun, because the baby can become dangerously overheated. A baby under the age of three months is unable to lose excess heat.
During car journeys, check frequently to make sure that the sun is not shining directly on the baby. Also, protect the baby's head from the sun.

Baby illnesses

When a baby becomes ill, he or she may or may not have a temperature above normal. A reading from a thermometer is an inaccurate guide to a baby's state of health.
Other warning signs also must be considered.
The most common noticeable signs that a baby has an infection or illness are a sudden loss of appetite; irritability or lethargy; and vomiting or diarrhea.
These signs are a more accurate indication than a temperature reading.
However, during an illness the physician may ask the parent to monitor the baby's temperature.
It is dangerous to place a thermometer in a baby's mouth and difficult to keep one underneath a baby's arm for a sufficient length of time.
The safest way to take the baby's temperature is with a rectal thermometer.
A rectal thermometer has a rounded, stub end. This type of thermometer can be used for taking oral temperatures as well, so when buying a thermometer, buy a rectal one.
Finally, do not keep a baby's room too hot if he or she is ill. If the baby has a high temperature, keep him or her covered with light clothes and a sheet.
The physician may recommend sponging with tepid water to keep the baby's temperature down.

Baby Rectal Temperature

Make sure that the mercury ribbon is first shaken below the thermometer's normal mark.
Then take the baby's rectal temperature using the method described below.
It usually takes three to five minutes for a rectal thermometer to register the body temperature. Although the normal body temperature varies from person to person, the average is 98.6°F (37°C) for an oral temperature, and 99.6°F (37.6°C) for a rectal temperature.
Wash the thermometer carefully after use with cool water and soap. An alcohol pad, available at drugstores, is also acceptable for cleaning thermometers.
Never use hot water because this will break the bulb.

Taking a rectal temperature: 

Lay the baby on his or her back.
Dip the end of the thermometer in petroleum jelly.
With one hand, hold the baby's legs up and gently insert the bulb into the anus.
Do not push if the thermometer meets an obstruction.
Slide the thermometer in about 1 inch (2.5 cm).