Neonates

A newborn should have a detailed physical examination that identifies normal characteristics and existing abnormalities and establishes a baseline for future physiologic changes.

The average head circumference is between 34 and 36cm for a full-term infant.

Head circumference may be less immediately after birth because due to molding process that occurs during a normal vaginal delivery.

By the second or third day after delivery the normal size and contour of the skull have replaced the molded one.

Chest circumference is 32 to 34cm and head circumference is usually about 2 to 3cm greater than chest circumference.

If the head is significantly smaller than the chest, microcephaly or premature closure of the sutures is considered.

If the head is more than 4cm larger than the chest in circumference and this relationship remains, hydrocephalus must be considered.

Increased head circumference also seen with caput succedeneum, cephalhematoma, and sub-dural hematoma.

Premature birth and malnutrition can cause the head measurement to be significantly larger than the chest circumference, due to decreased chest size.

Crown-to-rump measurements are from 31 to 35cm approximately equal to head circumference.

The relationship between the head and crown-to-rump measurements is more reliable than that between the head and chest.

Head-to-heel length is also measured, and the average length of the newborn is 52 to 54cm.

Body weight is measured soon after birth because weight loss occurs fairly rapidly.

The neonate loses about 10% of the birth weight by 3 to 4 days of age because of loss of excessive extracellular fluid, meconium, and limited food intake.

The birth weight is regained by the tenth day of life.

Most newborns weigh 2700 to 4000g.

The average weight of a newborn is about 3200-3400g.

Newborns who weigh below 2500g are generally classified as low-birth-weight infants.

Birth weights and lengths provide a baseline for assessment of future growth.

Axillary temperatures are taken because rectal thermometers can cause perforation of the mucosa, however examining the rectum for patency and neurologic innervation.

Core body temperature is usually 35.5 degrees Celsius-37.5 degree Celsius.

Pulse and respirations vary with infant’s behaviors but are usually in the range of 120 to 140 beats/minute and 30 to 60 breaths/minute, respectively.

Blood pressure is usually not taken in newborns, but the average systolic blood pressure is 70mm/Hg at 2 days of age, 84mm/Hg at 2 weeks, and 93mm/Hg at 6 weeks.

Neonates born to obese or overweight women are more likely to be large for gestational age.

Have well developed nociceptive pathways and are able to experience pain.

Staphylococcus aureus is a leading cause of healthcare associated infections in neonatal ICU’s.