All newborns should have weight, total length and head circumference recorded on admission along with the Ballard's score. Length and head circumference should be recorded every weekly. There is an initial weight loss of <15% in premature and < 10% in term infants till 4-6 days of life. The birth weight is reached by 10 days and by about 2 weeks of life age consistent growth is found and birth weight is surpassed. SGA babies do not have the initial loss of weight. Head circumference decrease by 0.5 cm in 1st week of life due to shift of fluid and then increases subsequently.
Premature infants usually attain the catch up head circumference by 18 months , catch-up weight by 24 months and catch-up height by 40 months. The indications of catch-up growth occur first in the head circumference, and then in length and weight.
Weight gain criteria
< 27 weeks gestation 10-20 gm/day.
27-40 weeks gestation 20-35 gm/day.
Birth - 6 months 25-35gm/day.
Catch-up growth Add 5-10 gm/day to above.
Head Size: The size of the head is a good indicator of the size of the brain. The head size at birth varies from 32-35 cm and increases by 12 cm in 1 st year to reach 43-46 cm at 1 year of age. Subsequently the head size increases gradually to reach an adult size of 48-51 cm at 5 years of age. Small head size (microcephaly) can occur due to infections in Pregnancy, genetic disorders and early closure of skull sutures. Large head (macrocephaly) can occur due to water accumulation in the cavities of the brain (hydrocephalus) or due to genetic disorders.
Anterior fontanelle: The soft part of the head is known as anterior fontanelle and is usually about 2.5 cm x 2.5 cm at birth. It closes by about 9-18 months of age. Delayed closure of anterior fontanelle occurs in patients with rickets (Vitamin D deficiency), hydrocephalus or genetic disorders.