Prematurity Pediatrics

NELSON’S 19TH EDITION
CHAPTER-91.2
Waldemar A. Carlo
Who(facts sheets 2016)
PREMATURITY AND INTRAUTERINE GROWTH
RETARDATION

KAUSAL KISHOR GANESH
GROUP-13-2
SEPTEMBER-14,2017

Objectives:
1. To define Prematurity and IUGR
2. To discuss the incidence and identify the cause of both
3. To discuss types of IUGR
4. To discuss the assessment of gestational age at birth
5. To discuss spectrum of disease in LBW infants
6. To discuss how to take proper care of preterm infants
7. To discuss the prevention of infection among premature infants

DEFINATIONS:
 Live-born infants delivered before 37 wks from the 1st day of the
last menstrual period are termed premature by the World Health
Organization
 LBW (birth-weight of 2,500g or less) is due to prematurity, poor
intrauterine growth (IUGR, also referred to as SGA), or both
 Prematurity and IUGR are associated with increased neonatal
morbidity and mortality

sub-categories of premature infants:
BASED ON GESTATIONAL
AGE; BASED ON WEIGHT;
i. extremely preterm
(<28 weeks)
ii. very preterm (28 to
<32 weeks)
iii. moderate to late
preterm (32 to <37
weeks).
i. Low birth weight
<2500g
ii. Very low birth
weight <1500g
iii. Extremely low birth
weight <1000g

Incidence:
 increasing percentage of deaths in children < 5 yr of age that
occur in the neonatal period
 57% of deaths in this age group occur within the 1st months of
life, of which approximately 36% are attributable to premature
birth
 30% of LBW infants in the USA have IUGR and are born after 37
wk.

 LBW rates > 10%, the contribution of IUGR increases and that
of prematurity decreases
 In developing countries, approximately 70% of LBW infants
have IUGR
 Infants with IUGR have greater morbidity and mortality than
do appropriately grown, gestational age – matched infants

Very low birthweight :
 VLBW infants weigh <1,500 g and are predominantly premature
 an accurate predictor of the infant mortality rate compared with
term infants,
 VLBW neonates have a higher incidence of re-hospitalization
during the 1st year of life for sequelae
prematurity,infections,neurologic complications, and psychosocial
disorders
 Perinatal care has improved the rate of survival of VLBW infants

FACTORS RELATED TO PREMATURE BIRTH
AND LOW BIRTHWEIGHT:
 Families of low socioeconomic status have higher rates of
maternal under-nutrition, anemia, and illness; inadequate
prenatal care; drug misuse; obstetric complications; and maternal
history of reproductive inefficiency
 Systematic differences in fetal growth have also been described
in association with maternal size, birth order, sibling weight,
social class, maternal smoking, and other factors

 etiology of preterm birth is multifactorial and involves a complex
interaction between fetal, placental, uterine, and maternal factors
 IUGR is associated with medical conditions that interfere with the
circulation and efficiency of the placenta, with the development or
growth of the fetus,or with the general health and nutrition of the
mother

IUGR:
Often classified as reduced growth that is:
SYMMETRIC ASYMMETRIC
 earlier onset
 associated with diseases that seriously
affect fetal cell number, such as
conditions with chromosomal,genetic,
malformation, teratogenic, infectious
 severe maternal hypertensive etiologies
 late onset
 demonstrates preservation of
Doppler waveform velocity to the
carotid vessels
 associated with poor maternal
nutrition
 with late onset or exacerbation of
maternal vascular disease
(preeclampsia, chronic
hypertension

ASSESSMENT OF GESTATIONAL AGE AT BIRTH:
 Ballard scoring system is accurate to ± 2 wk
 infant should be presumed to be at high risk for mortality or
morbidity if a discrepancy exists between the estimation of
gestational age by physical examination,the mother’s
estimated date of her last menstrual period, and fetal
ultrasonographic evaluation

Physical maturity score +Neuromuscular maturity score=Gestational age in weeks

SPECTRUM OF DISEASE IN LOW-BIRTHWEIGHT INFANTS:

NURSERY CARE:
 At birth, the measures needed to clear the airway, initiate
breathing, care for the umbilical cord and eyes, and administer
vitamin K are the same for immature infants as for those of normal
weight and maturity

Additional considerations are the needed :
i. thermal control and monitoring of the heart rate and
respiration
ii. oxygen therapy
iii. special attention to the details of fluid requirements and
nutrition.

THERMAL CONTROL:
 Optimal environmental temperature for minimal heat loss and
oxygen consumption for an unclothed infant is one that maintains
the infant ’s core temperature at 36.5-37.0°C
 the smaller and more immature the infant, the higher the
environmental temperature required
 Infant warmth can be maintained by heating the air to a desired
temperature

Kangaroo mother care:
 direct skin-to-skin contact and a hat and blanket covering the
infant is a safe alternative,with careful monitoring to avoid the risk
of serious hypothermia when incubators are unavailable or when
the infant is stable and the parents desire close contact with their
infant.

Administering oxygen:
 to reduce the risk of injury from hypoxia and circulatory
insufficiency must be balanced against the risk of hyperoxia to the
eyes (retinopathy of prematurity) and oxygen injury to the lungs
 concentration of inspired oxygen must be adjusted in accordance
with the oxygen tension of arterial blood (PaO2) or a noninvasive
method such as continuous pulse oximetry or transcutaneous
oxygen measurements

Fluid Requirements:
 Insensible water loss is indirectly related to gestational age;
a. very immature preterm infants (<1000g) may lose as much as
2-3 mL/kg/hr, partly because of immature skin, lack of
subcutaneous tissue, and a large exposed surface area
b. larger premature infant (2,000-2,500g) nursed in an incubator
may have an insensible water loss of approximately 0.6-0.7
mL/kg/hr

 Fluids intake in:
a. Term infants-60-70 mL/kg on day 1 and increased to 100-120
mL/kg by days 2-3
b. Smaller,more premature infants may need to start with 70-80
mL/kg on day 1 and advance gradually to 150 mL/kg/day
 Daily weights, urine output, and serum urea nitrogen and sodium
levels should be monitored carefully to determine water balance
and fluid needs

Total Parenteral Nutrition:
 goal of parenteral alimentation is to deliver sufficient calories
from glucose, protein, and lipids to promote optimal Growth
 infusate should contain 2.5-3.5 g/dL of synthetic amino acids and
usually 10-15 g/dL of glucose, in addition to appropriate
quantities of electrolytes, trace minerals, and vitamins.

 Peripheral vein is used, it is advisable to keep the glucose
concentration below 12.5 g/dl
 If central vein is used glucose concentrations as high as 25
g/dL may be used
 After caloric intake of >100 kcal/kg/24 hr is established by total
parenteral intravenous nutrition, the infants can be expected to
gain about 15 g/kg/24 hr

Feeding:
 Parental feeding:
infants with respiratory distress, hypoxia, circulatory insufficiency,
excessive secretions, gagging, sepsis, central nervous system
depression, severe immaturity, or signs of serious illness
 Bottle feeding:
Preterm infants at 34 wks of gestation or more

 Gavage feeding:
-Smaller or less vigorous infants
-infant may be fed with intermittent bolus feedings or continuous
feeding
-infant with feeding intolerance, nasojejunal feeding may be successful
 Breast- or bottle-feeding:
-may be instituted gradually as soon as an infant displays general
vigor adequate for oral feeding without fatigue

Initiation of Feeding:
 optimal time to introduce enteral feeding to a sick premature or LBW
infant is controversial
 Well babies without any distress can be orally fed, although most
infants weighing <1,500 g require tube feeding because they are unable
to coordinate breathing, sucking, and swallowing

 infants <1,000 g, the initial trophic feedings can be given at 10-
20 mL/kg/24 hr as a continuous nasogastric tube drip (or given
by intermittent gavage every 2-3 hr) for 5-10 days
 feeding protocol for premature infants weighing >1,500 g is
initiated at a volume of 20-30 mL/kg/24 hr with increments in
total daily formula volume of 20-30 mL/kg/24 hr
 Breast milk from their mothers is the preferred milk for all
infants,including VLBW infants

Vitamins:
 LBW and preterm infants should be given supplemental vitamins
 Intermediary metabolism of phenylalanine and tyrosine depends,
in part, on vitamin C
 VLBW infants are particularly prone to the development of
osteopenia due to decreased absorption of vit. D
 Folic acid is essential for the formation of DNA and production of
new cells

 Deficiency of vitamin E is uncommon but is associated with
increased hemolysis
 Vitamin E functions as an antioxidant to prevent the peroxidation
of excessive polyunsaturated fatty acids in red blood cell
membranes
 Vitamin A supplementation reduces bronchopulmonary dysplasia
in ELBW infants

Physiologic anemia:
 In LBW and premature infants,its due to postnatal suppression of
erythropoiesis is exacerbated by smaller fetal iron stores and
greater expansion of blood volume from the more rapid growth
than that of term infants
 iron supplementation (2 mg/kg/24 hr) should then be started
 If erythropoietin is used, iron supplementation is also required.

Prevention of Infection:
 Prevention strategies include strict compliance with:
a. Handwashing and universal precautions,
b. minimizing the risk of catheter contamination and duration,
c. meticulous skin care,
d. encouraging early appropriate advancement of enteral feeding,
e. education and feedback to staff, and
f. surveillance of nosocomial infection rates in the nursery

IMMATURITY OF DRUG METABOLISM:
 Renal clearance of almost all substances excreted in the urine is
diminished in newborn infants
 glomerular filtration rate rises with increasing gestational age
 Longer intervals are required for many drugs administered to
preterm infants
 administering any drug, particularly in high doses,that has not
undergone pharmacologic testing in premature infants should be
undertaken carefully after risks have been weighed against
benefits.

 Decisions about the choice and dose of antibacterial agents and
the route of administration should be made on an individual basis
rather than routinely because of the dangers of
(a) development of infections with organisms resistant to
antibacterial agents,
(b) inhibition of intestinal bacteria that manufacture significant
amounts of essential vitamins (vitamin K and thiamine), and
(c) harmful interference in important metabolic processes

PROGNOSIS:
 Infants born weighing 1,501-2,500 g have a 95% or greater
chance of survival, but those weighing still less have significantly
higher mortality
 postdischarge mortality rate of LBW infants is higher than that of
term infants during the 1st 2 yr of life
 premature infants have an increased incidence of failure to thrive,
sudden infant death syndrome, child abuse, and inadequate
maternal-infant bonding

 Congenital anomalies are present in approximately 3-7% of LBW
infants
 absence of congenital abnormalities, central nervous system
injury, VLBW, or marked IUGR, the physical growth of LBW
infants tends to approximate that of term infants by the 2nd yr
 greater the immaturity and the lower the birthweight,the greater
the likelihood of intellectual and neurologic deficit

 Many surviving LBW infants have hypotonia before 8 months
corrected age, which improves by the time they are 8 months to 1
years old
 Adolescents who were VLBW report satisfactory health; 94% are
integrated in regular classes despite neurosensory disabilities
(hearing, vision, cerebral palsy, cognition) in 24%
 Both premature and IUGR infants are at risk for significant
metabolic conditions

PREDICTING NEONATAL MORTALITY:
 Birthweight and gestational age-strong indicators for the risk of neonatal death
 Increasing gestational age, survival rates rise to approximately 15% at 23 wk, 56% at
24 wk, and 79% at 25 wk
 survival of infants of < 24 wk gestation, weighing < 750 g, and with a 1-min Apgar
score < 3 is 30%
 Prediction models-
a. Clinical Risk Index for Babies (CRIB)-1st 12 hr after birth
b. Score forNeonatal Acute Physiology (SNAP)-1st 24 hr after birth

DISCHARGE FROM THE HOSPITAL:
 premature infant should be taking all nutrition by nipple, either
bottle or breast
 Some medically fragile infants may be discharged home while
receiving gavage feedings after the parents have received
appropriate training and education
 Growth should be occurring at steady increments of approximately
30 g/day

Home-care:
 Ideally,home care program should include at least one home
visit by someone capable of evaluating domestic arrangements
and advising about any needed improvements
 Early developmental intervention programs focused on parent-
infant relationship and/or infant development after discharge is
more effective

Summary:
 Preterm birth is the leading cause of neonatal mortality and the
most common reason for antenatal hospitalization
 Confirmation of gestational age is based on physical and
neurologic characteristics
 Stabilization in the delivery room with prompt respiratory and
thermal management is crucial to the immediate and long-term
outcome of premature infants, particularly extremely premature
infants

 Preterm infants need intense monitoring of their fluid and
electrolytes because of increased transdermal water loss and
immature renal function in these infants, as well as various
environmental issues
 All infants should be breast fed exclusively
 If all major medical problems have resolved and the home setting
is adequate, premature infants may then be discharged when their
weight approaches 1,800-2,100 g; close follow-up plus easy
access to health care providers is essential for early discharge
protocols

Prematurity Pediatrics

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