Growth and development are the characteristics of
infancy and childhood. Growth occurs by both hyperplasia and
hypertrophy and can be measured in units that determine size.
It can be assessed by age-dependent and age-independent
parameters. Common age-dependent markers of growth are body
weight, length/height, head circumference and body mass index.
Growth monitoring is an invaluable, inexpensive, simple and
acceptable tool for assessing health status of a child.
Development, on the other hand, denotes capacity and
ability of an individual to integrate task performance,
coordination, language, and social and behavioral adjustment.
In general, growth and development go hand in hand in an
orderly, organized, sequential and predictable manner [1].
Neurodevelopmental delay is a state of severe, lifelong
impairment in areas of develop-ment that affects motor
functions, socio-emotional behavior, sensory function,
language, attention, memory and adaptive skills during the
early period of a child’s growth and development [2-4].
Neuro-development of a child is a result of complex interplays
between genetic, environmental and nutritional factors
profoundly affected by the intrauterine milieu and quality of
transition at birth from the intra uterine sojourn to extra
uterine existence. Intrauterine environment provides proper
physical moorings for growth and development of the fetus like
adequate temperature, moisture, and humidity; sufficient space
for movement and sensory stimuli from the maternal heart
beats, respiratory excursions, bowel sounds and locomotion;
effective barrier to trauma, noise, light, external thermal
changes and infection; constant supply of macro and micro
nutrients for daily requirement and body stores; development
of circadian rhythm for sleep and secretion of placental
neuro-steroid hormones for GABA neurotransmitter regulation
and neuroprotection; appreciation of smell from maternal
pheromones, which drives the infant towards breasts, and
immediate skin-to-skin touch at birth helps stabilizing the
infant; acquiring skills of sucking and swallowing of the
amniotic fluid; conferment of passive humoral immunity and yet
complete freedom to develop his/her own destiny. A shortened
intra uterine period will adversely affect the fetus in all
aspects described above. Preterm infant born too soon will be
at a disadvantage compared to his peers born at term because
adequate artificial ‘intrauterine care’ is a far cry today and
whether that will ever be available in future is a million
dollar question. Similarly a preterm infant subjected to
intrauterine growth restriction will be doubly disadvantageous
and will have greater risk of neurodevelopmental delay and
poor physical growth.
In this issue of the journal, Mukhopadhyay, et al.[5] and
Murki, et al. [6], from two different regions in India,
reiterate that a significant number of preterm or very low
birth weight infants suffer from growth failure and delays in
cognitive, language and neurodevelopment at corrected age of
12 months to two years. Infants with intrauterine growth
restriction, as expected, fared worse than appropriate for
gestation age peers. In another study from one of these
centers, Debata, et al. [7] had previously reported very high
prevalence of language delay in very low birth babies at 6-36
months of corrected age. Similar observations have made by
many authors from around the world.
A multifactorial
etiology contributes to growth and developmental delay. These
can be broadly divided into five categories: prenatal;
perinatal; neonatal; post neonatal; and miscellaneous causes.
Structural malfor-mations and metabolic injury of the brain,
genetic disorders, inborn errors of metabolism, early maternal
infections and maternal substance abuse during pregnancy,
preterm birth, intrauterine growth restriction, perinatal
asphyxia and hypoxic ischemic encephalopathy, neonatal sepsis,
hypoglycemia, micronutrient deficiency particularly iron and
folic acid deficiency and inadequate infant feeding practices,
especially deprivation of breastfeeding/breast milk feeding
and, poor social interaction and separation from the mother
are some of the important causes of neurodevelopmental delay.
Very preterm infants frequently require resuscitation in
the labor room, NICU care, ventilatory support, surfactant and
oxygen administration, body temperature management,
intravenous fluids, vasopressive agents, antibiotics, and
other medications like caffeine and PDA closing drugs. They
suffer from many metabolic derangements like hypoglycemia,
hypocalcemia and hypothermia; intraventricular hemorrhage and
acidosis with resultant neuronal insult and injury. Achieving
adequate enteral feeding of very preterm infants is a bigger
challenge. Bronchopulmonary dysplasia and permanent brain
damage are long term serious complications. Many of these
complications were present in the subjects of the two studies
[5,6].
In recent years, perinatologists have started
looking at the fetal physiology beyond intrauterine weight
gain and structural integrity. Sleep develops during fetal
life with a recognizable pattern of sleep states in the
preterm fetus associated with the development, maturation and
neural connectivity within the brain. Impaired sleep
development in the preterm infant may lead to altered
neurocognitive, behavioral and motor capabilities in infancy
and childhood and later on as adult [8]. Sleep is greatly
disturbed in a preterm infant due to NICU protocols, noise,
and intense light that may affect neurodevelopment.
It
is, therefore, essential that assessment and monitoring of
growth and development of all infants and children, especially
high risk infants, should be carried out from early life.
There is convincing scientific evidence that early
identification of developmental delays and appropriate early
intervention improve a child’s long-term outcome and prognosis
[10].
Competing interests: None stated; Funding: None.
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