Low Birth Weight (LBW).pdf

A condition that links Obstetricians and Paediatricians.

1. PAEDIATRICS AND CHILD HEALTH
•NEONATOLOGY
•Low Birth Weight (LBW)
Dr.ChongoShapi(BSc.HB, MBChB, CUZ)
-Medical Doctor.
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2. Definitions
•Remember: gestation is divided into 3 trimesters
-1
st
trimester = 1
st
12 weeks
-2
nd
trimester = 13-24 weeks
-3
rd
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
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3. •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 fetusbefore 24 wks= miscarriage
•A baby born dead after 24 wksis a stillbirth
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4. •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 yrof life for
sequelaeof prematurity, infections, neurologic
complications, and psychosocial disorders
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5. Variations in Neonatal Mortality Based on BW, GA, and Gender
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6. 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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7. 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
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8. Identifiable Causes of Preterm Birth
Fetal
•Fetaldistress
•Multiple gestation
•Erythroblastosis
•Nonimmunehydrops
Placental
•Placental dysfunction
•Placenta previa
•Abruptioplacentae
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9. 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: Bicornuateuterus, Incompetent
cervix (premature dilatation)
•Drug abuse (cocaine)
Other
•Premature rupture of membranes
•Polyhydramnios
•Iatrogenic
•Trauma
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10. Intrauterine Growth Restriction (IUGR)
•Is a condition in which the baby is pathologically
deprived to grow to its full genetic potential
•Birth weight is < 10
th
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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11. 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 fetalresponse 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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12. 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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13. 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

14. 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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15. Factors Associated with IUGR
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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16. Factors Associated with IUGR
Placental
•Decreased placental weight or cellularity, or both
•Decrease in surface area
•Villous placentitis(bacterial, viral, parasitic)
•Infarction
•Tumour (chorioangioma, hydatidiformmole)
•Abruptioplacenta
•Twin-twin transfusion syndrome (TTTS)
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17. Factors Associated with IUGR
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)
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18. Problems of IUGR (SGA)
PROBLEMvsPATHOGENESIS
•Intrauterine fetaldemise (IUFD): Hypoxia, acidosis,
infection, lethal anomaly
•Perinatal asphyxia: ↓ Utero-placental perfusion
during labour ±chronic fetalhypoxia-acidosis;
meconium aspiration syndrome
•Hypoglycemia: ↓ Tissue glycogen stores, ↓
gluconeogenesis, hyperinsulinism, ↑ glucose needs
of hypoxia, hypothermia, large brain
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19. Problems of IUGR (SGA)
•Polycythemia-hyperviscosity: Fetalhypoxia 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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20. 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
fetalweight
•The Ballard scoring system is accurate to +/-2 weeks
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21. 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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24. 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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25. 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
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26. Neonatal Problems Associated with Premature Infants
Common ones are highlighted in red
Respiratory
•Respiratory distress syndrome (hyaline
membrane disease)
•Bronchopulmonarydysplasia
•Pneumothorax, pneumomediastinum; interstitial
emphysema
•Congenital pneumonia
•Pulmonary hypoplasia
•Pulmonary haemorrhage
•Apnea
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27. Neonatal Problems Associated with Premature Infants
Cardiovascular
•Patent ductusarteriosus
•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
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28. Neonatal Problems Associated with Premature Infants
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
•Euthyroidbut low-
thyroxinestatus
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29. Neonatal Problems Associated with Premature Infants
Central Nervous System
•Intraventricularhemorrhage
•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)
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30. 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
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31. 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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32. 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 D10Wfor 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 1
st
48 hrsfor 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 1
st
wk, then 100-150 kcal/kg/d onwards
Term: 60-80 kcal/Kg/d in 1
st
wk, then 80-120 kcal/kg/d onwards
NB: the more premature the baby, the more the energy requirement
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33. 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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34. Sequelaeof LBW
IMMEDIATE vsLATE
•Hypoxia, ischemia: Mental retardation, spastic
diplegia, microcephaly, seizures, poor school
performance
•Intraventricularhemorrhage: Mental retardation,
spasticity, seizures, hydrocephalus
•Sensorineuralinjury:Hearing, visual impairment,
retinopathy of prematurity, strabismus, myopia
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35. Sequelaeof LBW
•Respiratory failure: Bronchopulmonarydysplasia,
corpulmonale, bronchospasm, malnutrition,
subglottic stenosis, iatrogenic cleft palate,
recurrent pneumonia
•Necrotizing enterocolitis: Short-bowel syndrome,
malabsorption, malnutrition, infectious diarrhea
•Cholestaticliver disease: Cirrhosis, hepatic
failure, hepatic carcinoma, malnutrition
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36. Sequelaeof 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 ductusarteriosusligation, intravenous
infiltration), gastroesophagealreflux,
hypertension, craniosynostosis, cholelithiasis,
nephrocalcinosis, cutaneous hemangiomas
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37. The End!
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