Low Birth Weight (LBW).pdf

PAEDIATRICS AND CHILD HEALTH
• NEONATOLOGY
• Low Birth Weight (LBW)
Dr. Chongo Shapi (BSc.HB, MBChB, CUZ)
- Medical Doctor.
3/20/2022 Dr. Chongo Shapi, BSc.HB, MBChB, CUZ. 1

Definitions
• Remember: gestation is divided into 3 trimesters
- 1st trimester = 1st 12 weeks
- 2nd trimester = 13-24 weeks
- 3rd trimester = 25-42 weeks
• According to WHO, the baby becomes potentially
viable after 24 weeks gestational age (GA)
- In Zambia, after 28 weeks
• Term = 37-42 completed weeks
• Expected date of delivery (EDD) duration = 40wks
• Post-dates = after EDD but before 42 weeks
• Post-term = after 42 completed weeks
• Preterm = 24 to 36 completed weeks
3/20/2022
Dr. Chongo Shapi, BSc.HB, MBChB, CUZ.
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• Thus, a premature baby = baby born in preterm
period
• A premature baby has potential to thrive but not
on its own because other organs are not yet
mature (e.g. lungs) to make it survive on its own
• These babies, thus need to be incubated and taken
care off in neonatal intensive care unit (NICU)
• At UTH this is D-block
• Post-term baby = baby born after 42 completed
weeks
• Expulsion of the products of conception or embryo
or fetus before 24 wks = miscarriage
• A baby born dead after 24 wks is a stillbirth
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• Low birth weight (LBW) = birth weight ≤ 2.5Kg
• Very LBW (VLBW) = birth weight ≤ 1.5Kg
• Extremely LBW (ELBW): birth weight ≤ 1Kg
• LBW or VLBW is due to prematurity, poor
intrauterine growth (IUGR), or both
• Prematurity and IUGR are associated with
increased neonatal morbidity and mortality
• VLBW neonates have a higher incidence of re-
hospitalization during the 1st yr of life for
sequelae of prematurity, infections, neurologic
complications, and psychosocial disorders

Variations in Neonatal Mortality Based on BW, GA, and Gender
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Factors Related To Premature Birth and LBW
• It is difficult to separate completely the factors associated
with prematurity from those associated with IUGR
• A strong positive correlation exists between both preterm
birth and IUGR and low socioeconomic status
• Families of low socioeconomic status have higher rates of:
- Maternal under-nutrition
- Anaemia and illness
- Inadequate prenatal care
- Drug misuse
- Obstetric complications
- Maternal histories of reproductive inefficiency (abortions,
stillbirths, premature or LBW infants)
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Factors Related To Premature Birth and LBW
• Other associated factors:
- Single-parent families
- Teenage pregnancies
- Short inter-pregnancy interval
- Grand multipara
- Maternal smoking
• The degree to which the variance in birth-weight
among various populations is due to
environmental (extra-fetal) rather than genetic
differences in growth potential is difficult to
determine

Identifiable Causes of Preterm Birth
Fetal
• Fetal distress
• Multiple gestation
• Erythroblastosis
• Nonimmune hydrops
Placental
• Placental dysfunction
• Placenta previa
• Abruptio placentae
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Maternal
• Pre-eclampsia
• Chronic medical illness (cyanotic heart disease, renal
disease)
• Infection (Listeria monocytogenes, group B streptococcus,
urinary tract infection, bacterial vaginosis, chorioamnionitis)
• Uterine abnormalities: Bicornuate uterus, Incompetent
cervix (premature dilatation)
• Drug abuse (cocaine)
Other
• Premature rupture of membranes
• Polyhydramnios
• Iatrogenic
• Trauma

Intrauterine Growth Restriction (IUGR)
• Is a condition in which the baby is pathologically
deprived to grow to its full genetic potential
• Birth weight is < 10th percentile according to gestation
age
• Several factors act to cause this reduced growth,
hence aetiology is multifactorial
• Involves a complex interaction between the following
factors:
- Fetal
- Placental
- Maternal, including uterine factors
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Intrauterine Growth Restriction (IUGR)
• IUGR is NOT equal to small for gestational age (SGA)
• But SGA can be secondary to IUGR
• SGA is where the baby is just small for the gestation age because
of:
1. IUGR
2. Baby is born from a ‘small’ mother
• IUGR may be a normal fetal response to nutritional or oxygen
deprivation
• Therefore, the issue is not the IUGR but rather the on-going risk
of malnutrition or hypoxia
• Similarly, some preterm births signify a need for early delivery
from a potentially disadvantageous intrauterine environment
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Classification of IUGR
• Is classified into:
1. Symmetrical IUGR
2. Asymmetrical IUGR
• Symmetric IUGR = head circumference, length,
and weight are equally affected
• Asymmetric IUGR = there is relative sparing of
head growth
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Classification of IUGR
• Symmetrical
- Incidence: 20%
- Onset: from start
- Brain is NOT spared
- Prognosis is BAD due to lack of
potential for growth
- Amniotic fluid volume: normal
- Is associated with diseases that
seriously affect the cell number:
genetic, chromosomal,
malformation or severe
maternal hypertensive
aetiologies
• Asymmetrical
- Incidence: 80%
- Onset: later
- Brain is spared
- Prognosis is BETTER due to
suspension of growth
- Amniotic fluid volume: reduced
- Is associated with poor maternal
malnutrition or with late onset
or exacerbation of maternal
vascular diseases in pregnancy
e.g. pre-eclampsia

Factors Associated with IUGR
• Is associated with medical conditions that
interfere with:
1. Circulation and efficiency of the placenta
2. Development or growth of the fetus
3. General health and nutrition of the mother
• Many factors are common to both prematurely
born and LBW infants with IUGR
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Fetal
Chromosomal disorders (autosomal trisomies: 18,21
and 13)
• TORCHES infections
• Congenital anomalies—syndrome complexes
• Irradiation
• Multiple gestation
• Pancreatic hypoplasia
• Insulin deficiency
• Insulin-like growth factor type I deficiency
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Placental
• Decreased placental weight or cellularity, or both
• Decrease in surface area
• Villous placentitis (bacterial, viral, parasitic)
• Infarction
• Tumour (chorioangioma, hydatidiform mole)
• Abruptio placenta
• Twin-twin transfusion syndrome (TTTS)

Maternal
• Hypertensive disorders: pre-eclampsia, renal disease
• Malnutrition (micro- or macronutrient deficiencies)
• Sickle cell disease (SCD)
• Malaria
• Epilepsy
• Drugs (narcotics, alcohol, cigarettes, cocaine,
antimetabolites)
• Chronic illness e.g. malignancy, IBD
• Toxemia
• Hypoxemia (high altitude, cyanotic cardiac or
pulmonary disease)

Problems of IUGR (SGA)
PROBLEM vs PATHOGENESIS
• Intrauterine fetal demise (IUFD): Hypoxia, acidosis,
infection, lethal anomaly
• Perinatal asphyxia: ↓ Utero-placental perfusion
during labour ± chronic fetal hypoxia-acidosis;
meconium aspiration syndrome
• Hypoglycemia: ↓ Tissue glycogen stores, ↓
gluconeogenesis, hyperinsulinism, ↑ glucose needs
of hypoxia, hypothermia, large brain

Problems of IUGR (SGA)
• Polycythemia-hyperviscosity: Fetal hypoxia with
↑ erythropoietin production
• Reduced oxygen consumption/hypothermia:
Hypoxia, hypoglycemia, starvation effect, poor
subcutaneous fat stores
• Dysmorphology: Syndrome anomalads,
chromosomal-genetic disorders, oligohydramnios-
induced deformation, TORCH infection
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The Ballard Score
• Is a scoring system that assess the gestational age (GA) at
birth
• Consists of 2 parts:
1. Physical maturity
2. Neuromuscular maturity
• When compared with a premature infant of appropriate
weight, an infant with IUGR has a reduced birth weight and
may appear to have a disproportionately larger head relative
to body size; infants in both groups lack subcutaneous fat
• Neurologic maturity (nerve conduction velocity), in the
absence of asphyxia, correlates with GA despite reduced
fetal weight
• The Ballard scoring system is accurate to +/- 2 weeks
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Things to Check in Ballard Score
• Physical Maturity
- Skin
- Lanugo
- Plantar surface
- Breast
- Eye/ear
- Genitals:
Male
Female
• Neuromuscular Maturity
- Posture
- Square window (wrist)
- Arm recoil
- Popliteal angle
- Scarf sign
- Heel to ear
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Maturity Rating
Score Weeks
- 10 20
- 5 22
0 24
5 26
10 28
15 30
20 32
25 34
30 36
35 38
40 40
45 42
50 44
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Spectrum of Disease in LBW infants
• Immaturity increases the severity the clinical
manifestations of most neonatal diseases
• Immature organ function, complications of
therapy, and the specific disorders contribute to
neonatal morbidity and mortality associated with
premature, LBW infants
• Among VLBW infants, morbidity is inversely
related to birth weight
• Poor postnatal growth is an important problem
for both preterm and IUGR infants

Neonatal Problems Associated with Premature Infants
Common ones are highlighted in red
Respiratory
• Respiratory distress syndrome (hyaline
membrane disease)
• Bronchopulmonary dysplasia
• Pneumothorax, pneumomediastinum; interstitial
emphysema
• Congenital pneumonia
• Pulmonary hypoplasia
• Pulmonary haemorrhage
• Apnea

Cardiovascular
• Patent ductus arteriosus
• Hypotension
• Hypertension
• Bradycardia (with apnea)
• Congenital malformations
Hematologic
• Anemia (early or late
onset)
• Subcutaneous, organ
(liver, cranial, adrenal)
hemorrhage
• DIC
• Vitamin K deficiency
• Hydrops—immune or
nonimmune

Gastrointestinal
• Poor gastrointestinal
function—poor motility
• Necrotizing enterocolitis
(NEC)
• Hyperbilirubinemia—
direct and indirect
• Congenital anomalies
producing polyhydramnios
• Spontaneous
gastrointestinal isolated
perforation
Metabolic-Endocrine
• Hypocalcemia
• Hypoglycemia
• Hyperglycemia
• Late metabolic acidosis
• Hypothermia
• Euthyroid but low-
thyroxine status
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Central Nervous System
• Intraventricular hemorrhage
• Periventricular leukomalacia
• Hypoxic-ischemic
encephalopathy (HIE)
• Seizures
• Retinopathy of prematurity
• Deafness
• Hypotonia
• Congenital malformations
• Kernicterus (bilirubin
encephalopathy)
• Drug (narcotic) withdrawal
Renal
• Hyponatremia
• Hypernatremia
• Hyperkalemia
• Renal tubular acidosis
• Renal glycosuria
• Oedema
Other
• Infections (congenital,
perinatal, nosocomial:
bacterial, viral, fungal,
protozoal)

Nursery care
• Clear the airway, initiate breathing, care for the
umbilical cord and eyes, and administer vitamin K
• Special care is required to maintain a patent
airway and avoid potential aspiration of gastric
contents
• Additional considerations are the need for:
1. Thermal control and monitoring of the heart rate
and respiration
2. Oxygen therapy
3. Special attention to the details of feeding

IVFs
• IVFs:
Preterm neonates need intense monitoring of
IVFs/electrolytes
- Increased transdermal water loss
- Immature renal function
- Environmental issues (eg, radiant warming, phototherapy,
mechanical ventilation)
Expected loss of ECF in the first week of life:
- Term: 5% of Bwt
- LBW: 10% of Bwt
- ELBW: 15-20% of Bwt
NB: The smaller the baby, the more fluid you give because of
the large surface area which facilitate loss of water
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Concepts of IVFs and Feeding in Neonates
Maintenance IVFs
To be given until oral feeds fully established. Total not to exceed 150
mL/kg/d.
- 50 mLs/8hrly D10W for the first 3 days
- Then, change to ¼ SD solution
- Subtract oral feed volume tolerated from total fluid requirement from
that day
- Wean off IVF once tolerating full feeds orally
NPO for 1st 48 hrs for preterm babies
• Start priming (EBM) on day 3: 80 mL/Kg
• Then, day 4 onwards: 120-200 mL/kg/d
Thermal Energy Requirement :
Preterm: 50-90 kcal/kg/d in 1st wk, then 100-150 kcal/kg/d onwards
Term : 60-80 kcal/Kg/d in 1st wk, then 80-120 kcal/kg/d onwards
NB: the more premature the baby, the more the energy requirement

Nursery care
• Safeguards against infection can never be relaxed
• Routine procedures that disturb these infants may
result in hypoxia
• Regular and active participation by the parents in
the infant's care in the nursery
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Sequelae of LBW
IMMEDIATE vs LATE
• Hypoxia, ischemia: Mental retardation, spastic
diplegia, microcephaly, seizures, poor school
performance
• Intraventricular hemorrhage: Mental retardation,
spasticity, seizures, hydrocephalus
• Sensorineural injury: Hearing, visual impairment,
retinopathy of prematurity, strabismus, myopia

Sequelae of LBW
• Respiratory failure: Bronchopulmonary dysplasia,
cor pulmonale, bronchospasm, malnutrition,
subglottic stenosis, iatrogenic cleft palate,
recurrent pneumonia
• Necrotizing enterocolitis: Short-bowel syndrome,
malabsorption, malnutrition, infectious diarrhea
• Cholestatic liver disease: Cirrhosis, hepatic
failure, hepatic carcinoma, malnutrition
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Sequelae of LBW
• Nutrient deficiency: Osteopenia, fractures,
anemia, vitamin E, growth failure
• Social stress: Child abuse or neglect, failure to
thrive, divorce
• Other: Sudden infant death syndrome, infections,
inguinal hernia, cutaneous scars (chest tube,
patent ductus arteriosus ligation, intravenous
infiltration), gastroesophageal reflux,
hypertension, craniosynostosis, cholelithiasis,
nephrocalcinosis, cutaneous hemangiomas
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The End!
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Low Birth Weight (LBW).pdf

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