Low Birth weight, Small for Gestational Age & Prematurity

Dr Mrs. Marcia Morayo Ihekaike

MBBS, FMCPaed, LMIH

Outline

• Objectives
• Introduction
• Definitions
• Incidence
• Classification
• Etiology
• Problems
• Management
• Prevention

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Objectives

• Know the definitions of the terms: LBW, SGA, Prematurity
• Know the classifications of LBW, SGA, Prematurity
• Know the causes of each clinical condition
• Understand the problems of each clinical conditions
• Understand the principles of management of the babies with these clinical conditions.

Introduction

• The birth weight of a child is the single most important determinant of survival, growth and development of the infant.
• The birth weight also reflects the mother’s health status during her adolescent period, during pregnancy and also reflects the quality of ANC received.
• Infants can be classified according to birth weight and/or gestational age.
• Low birth weight continues to be a significant public health problem globally and is associated with a range of both short- and long-term consequences.

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• Example: Preterm low birth weight is an infant whose gestational age is less than 37 completed weeks and weighing less than 2.5kg body weight.

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• Each category has related specific morbidities ad mortalities associated with it.

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• For instance, LBW is associated with higher morbidity/mortality, impaired immune function, and poor cognitive development for neonates

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Definitions

• Birth weight: the first weight obtained after birth (preferably within an hour)

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• Low birth weight (LBW): are those babies weighing < 2500gm (<5 pounds) at birth.

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• Gestational age: from first day of LMP to day of delivery; 280-286 days (approx. 40 weeks)

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• Preterms: are those babies delivered before 37completed weeks (less than 259 days)

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• Small for gestational age (SGA): birth weight that is more than two standard deviations below the mean or less than the 10^th percentile of a population-specific birth weight versus gestational age plot

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Incidence

• Overall, it is estimated that 15% to 20% of all births worldwide are LBW, representing more than 20 million births a year.
• Preterm birth is the most common direct cause of neonatal mortality.
• Every year, 1.1 million babies die from complications of preterm birth.
• Regional estimates of LBW include 28% in south Asia, 13% in sub-Saharan Africa and 9% in Latin America

• An estimated 15 million babies are born too early every year. That is more than 1 in 10 babies.
• Approximately 1 million children die each year due to complications of preterm birth.
• Globally, prematurity is the leading cause of death in children under the age of 5 years.
• More than 60% of preterm births occur in Africa and South Asia, but preterm birth is truly a global problem
• Nigeria ranks 3^rd among the countries with the highest number of preterm births globally.
• Approximately 15% of all births in Nigeria are low birth weight

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Classification

• Low birth weight babies can be classified into three namely;
• 1) Extreme low birth weight (ELBW): babies weighing < 1kg/1000g at birth.
• 2) Very low birth weight (VLBW): babies weighing between 1000g and 1499g at birth.
• 3) Low birth weight : babies weighing between 1500g and 2499g at birth.

• Preterm babies can be classified into:
• Extremely preterm (<28 weeks gestation)
• Very preterm (28 to <32 weeks gestation)
• Moderate to late preterm (32 to <37 weeks gestation)

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• Babies can be classified based on their gestational age into:
• Small for gestational age (SGA)
• Large for gestational age (LGA)
• Appropriate for gestational age (AGA)

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Classification of SGA

1. Asymmetrical SGA:
1. Primarily affecting weight; head circumference and skeletal growth normal
2. Maternal starvation, late onset hypertension, advanced DM are causes
3. Interfering with oxygen and nutrients transfer at stage of cellular hypertrophy
4. Has late onset
5. Prognosis is good

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2. Symmetrical SGA:
1. Both weight and height adversely affected; proportionate reduction in head and skeleton (long-term malnutrition)
2. Congenital infections, chromosomal/ genetic disorders, teratogenic, malformations, severe maternal hypertensive etiology
3. Injury occur early – stage of cellular hyperplasia
4. Prognosis is guarded

Intrauterine Growth Chart

Etiology

• More than 60 percent of low-birth weight babies are preterm.

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• The earlier a baby is born, the lesser the weight is likely to be.

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• Some preterms born near term, at around 35 to 37 weeks may not have low birth weight.

• Small-for-gestational age babies (a.k.a. small for date age or "growth-restricted") may be full-term but underweight.

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• Preterm LBW SGA infants results, at least partly, from:
• slowing or temporary halting of growth in the womb
• due to interference with the circulation and efficiency of the placenta,
• or with the development or growth of the fetus,
• or with the general health and nutrition of the mother.

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• Preterm, LBW AGA results from:
• inability of the uterus to retain the fetus,
• interference with the course of pregnancy,
• PROM
• premature separation of the placenta,
• multifetal gestation,
• or an undetermined stimulus to effective uterine contractions before term.

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• The etiology of preterm birth is multifactorial and involves a complex interaction between fetal, placental, uterine, and maternal factors

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Causes of Preterm LBW

Causes of Preterm LBW

Causes of SGA

Peculiarities of the Preterm

• Ability to suck, swallow, and breathe in a coordinated fashion is not achieved until 34–36 weeks' gestation.

• Frequent gastroesophageal reflux and an immature gag reflex, which increases the risk of aspiration of feedings

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• Decreased ability to maintain body temperature

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• Pulmonary immaturity-surfactant deficiency, often with structural immaturity in neonate less than 26 weeks' gestation.

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• Their condition is complicated by the combination of noncompliant lungs and an extremely compliant chest wall

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• Immature control of respiration, leading to apnea and bradycardia

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• Persistent patency of the ductus arteriosus, leading to further compromise of pulmonary gas exchange because of overperfusion of the lungs

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• Immaturity of metabolic processes

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• Immature cerebral vasculature, predisposing to subependymal or intraventricular hemorrhage and periventricular leukomalacia

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• Impaired substrate absorption by the GI tract

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• Immature renal function (including both filtration and tubular functions) complicating fluid and electrolyte management.

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• Increased susceptibility to infection

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Problems of Preterm LBW

Respiratory

• Respiratory distress syndrome
• Pulmonary hypoplasia
• Apnea of prematurity
• Air leaks leading to pneumothorax, pneumomediastinum
• Bronchopulmonary dysplasia
• Congenital pneumonia

Cardiovascular

• Patent ductus arteriosus
• Hypotension, hypertension
• Congenital cardiac malformations

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Central nervous system

• Intraventricular haemorrhage
• Periventricular leukomalacia
• Seizures
• Bilirubin encephalopathy
• Hypotonia

Renal

• Electrolyte imbalance (hyponatraemia, hypernatraemia, hyperkalaemia)
• Acid-base disturbances
• Renal failure
• Renal glycosuria
• Renal tubular acidosis

Ophthalmologic

• Retinopathy of prematurity
• Strabismus
• Myopia

Gastrointestinal-nutritional

• Feeding intolerance due to poor motility
• Necrotizing enterocolitis
• Inguinal hernias
• Spontaneous gastrointestinal isolated perforation
• Hyperbilirubinaemia- direct and indirect

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Immunologic

• Poor defence to infection

Metabolic

• Hypoglycaemia
• Hyperglycaemia
• Hypothermia
• Hypocalcaemia
• Hypomagnesaemia
• Hyperthermia
• Late metabolic acidosis

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Haematologic

• Anaemia
• Hyperbilirubinaemia
• Polycythaemia
• Ecchymoses
• Petechiae haemorrhages
• Vitamin K deficiency
• Hydrops

Miscellaneous

• Birth Asphyxia
• Infections (congenital, perinatal, nosocomial)

Problems of SGA

Problems of SGA

Management

• Principles
• Delivery room care
• Assessment of gestational age (Dubowitz score, New Ballard score)
• Warmth: Temperature/humidity control
• Feeding and hydration
• Detection and management of complications like: Respiratory distress, infection
• Close monitoring

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Management Of The Problem

Perinatal management

• Pregnancy ultrasonography
• Factors such as condition of fetal membranes
• Presence or absence of chorioamnionitis
• Adequate information to prospective parents
• Get parents involved with proposed management
• Caesarean delivery recommended if fetal distress is suspected or anticipated.

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• Management with tocolytics e.g. magnesium sulphate or ritodrine and betamethasone for lung maturation

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Delivery room management

• Principle of prevention of any physiologic deviation from normal e.g. hypothermia, acidosis, hypoxia
• Expert resuscitation in the delivery room
• Good thermoregulation
• Minimal handling and avoidance of brisk manoeuvres

• Expert cardiorespiratory support
• Intubation when indicated, endo-tracheal tube of 2.5mm
• Continuous monitoring of oxygenation with pulse oximetry
• Monitoring of blood pressure
• Catheterization of umbilical vessels if indicated
• Blood gases, blood glucose
• Administration of surfactant if indicated
• Parental information
• Total parental nutrition (TPN) after 48hrs
• Cranial ultrasound necessary in first 24hrs,can be repeated 1 week later depending on the prognosis

Respiratory Support

Cardiovascular support

• PDA documentation with echocardiography

Fluids and electrolytes

• Avoid fluid overload
• Avoid dehydration
• Manage in incubator
• Correct for hypernatremia
• Correct for hyponatremia
• Correct for hyperkalaemia
• Correct for hypoglycaemia

Warmth

• As for all newborns:
• Lay newborn on mother’s abdomen or other warm surface
• Dry newborn with clean (warm) cloth or towel
• Remove wet towel and wrap/cover with a second dry towel
• Bathe after temperature is stable
• KMC

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Feeding

Early and exclusive breastfeeding

• Breast milk = best nourishment
• Already warm temperature
• Facilitated by kangaroo care

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Kangaroo Mother Care (KMC)

• It is a special way of caring of low birth weight babies.
• It fosters their health and well being by promoting effective thermal control, breastfeeding, infection prevention and bonding.
• The baby is continuously kept in skin-to-skin contact by the mother and breastfed exclusively to the utmost extent.
• KMC is initiated in the hospital and continued at home

Components of KMC

• There are two components:
• Skin-to-skin contact: �Early, continuous and prolonged skin-to-skin contact between the mother and her baby is the basic component of KMC. The infant is placed on her mother's chest between the breasts.
• Exclusive breastfeeding: �The baby on KMC is breastfed exclusively. Skin-to-skin contact promotes lactation and facilitates the feeding interaction.

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Pre-requisite of KMC

• Support to the mother in hospital and at home: 
• A mother cannot successfully provide KMC all alone.
• She would require counseling along with supervision from care-providers, and assistance and cooperation from her family members.

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• Post-discharge follow up: 
• KMC is continued at home after early discharge from the hospital.
• A regular follow up and access to health providers for solving problem are crucial to ensure safe and successful KMC at home.

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Benefits of KMC

• Breastfeeding: �KMC results in increased breastfeeding rates as well as increased duration of breastfeeding.
• Thermal control: 
• Prolonged skin-to-skin contact between the mother and her preterm/ LBW infant provides effective thermal control with a reduced risk of hypothermia.
• For stable babies, KMC is equivalent to conventional care with incubators in terms of safety and thermal protection.

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• Early discharge: 
• LBW infants could be discharged from the hospital earlier than the conventionally managed babies.
• They gain more weight on KMC than on conventional care.

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• Less morbidity:
• Babies receiving KMC have more regular breathing and less predisposition to apnea.
• KMC protects against nosocomial infections.
• KMC is associated with reduced incidence of severe illness including pneumonia during infancy.

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• Other effects: 
• Mothers are less stressed during kangaroo care as compared with a baby kept in incubator.
• Mothers prefer skin-to-skin contact to conventional care.
• There is a stronger bonding with the baby, increased confidence, and a feeling of deep satisfaction that they are able to do something special for their babies.
• Fathers feel more relaxed, comfortable and better bonded while providing kangaroo care.

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Prevention of Low Birth weight

• It is difficult to predict which women are going to deliver preterm.
• But when a woman develops preterm labor, a medication (a tocolytic) may prevent preterm delivery (often for only a day or two, but even such a short delay can be helpful).
• With adequate prenatal care, many problems can be identified early (allowing treatment that may reduce their risk of having a low-birth weight baby).

Prevention: Pre-Pregnancy

• A pre-pregnancy visit to the hospital is especially crucial for women with chronic disorders such as diabetes and high blood pressure. Good control of these disorders, starting before pregnancy, reduces the risk of pregnancy complications.
• All women can benefit from early advice on good nutrition, as well as stopping risky behaviors, especially smoking, drinking alcohol and taking unprescribed drugs.
• Once pregnant, early and regular antenatal care.
• Prenatal intake of folic acid throughout pregnancy may reduce the risk of having a preterm and low-birth weight baby.��

Prevention: During Pregnancy

• Early & regular antenatal care.

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• Good nutrition.

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• Adequate weight gain (normally a woman gains weight gain 25 to 35 pounds (11 to 16 kilograms) during pregnancy.

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Prevention of Medical Problems in Preterm LBW

• Use of corticosteroids to speed maturation of the fetal lungs, thereby reducing incidence of RDS (by 50 percent) and bleeding in the brain (by 70 percent).

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• Corticosteroids are given by injection, and are most effective when administered at least 24 hours before delivery.

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Thank you for listening

QUESTIONS

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