Lecture #9: Assessment of feeding and growth in small for gestational age infants

How is Small for Gestational Age (SGA) defined?

SGA is defined as a birth weight less than the 10th percentile on a standardized growth chart for sex and gestational age.

When was the definition of SGA first used, and when did WHO adopt it?

The definition of SGA has been used since the 1960s and was adopted by the WHO in 1995.

What are some alternative definitions of SGA?

Alternative definitions of SGA include birth weight below the 3rd percentile, 5th percentile, or more than 2 standard deviations below the mean (50th percentile).

Besides birth weight, what other measurements may be affected in SGA infants?

Length and head circumference may also be affected, depending on the degree of intrauterine restriction.

What does IUGR stand for?

IUGR stands for intrauterine growth restriction

What is the key difference between SGA and IUGR?

SGA describes the infant after birth, while IUGR describes the fetus before birth

How are SGA infants classified based on the timing of IUGR?

SGA infants are classified as symmetrical or asymmetrical based on the timing of IUGR

What characterizes early IUGR?

Early IUGR results in symmetrical growth restriction, where all anthropometric measures are below the 10th percentile

What characterizes late IUGR?

Late IUGR causes asymmetrical growth restriction, where head circumference is spared, length may be mildly to moderately affected, and weight is significantly affected

Are all SGA infants affected by IUGR?

No, some SGA infants are constitutionally small and not the result of IUGR. However, all IUGR infants are SGA

True or false: all IUGR infants are SGA

True

What is Rohrer's Ponderal Index (PI)?

Rohrer's Ponderal Index (PI) is the ratio of weight (kg) to length (m³).

What does a PI greater than 2.41 indicate?

A PI > 2.41 indicates no length sparing and suggests chronic IUGR, with growth restriction occurring early in pregnancy (shortly after conception or within the first trimester)

What does a PI less than 2.41 indicate?

A PI < 2.41 represents length sparing and suggests acute or subacute IUGR that occurred later in pregnancy

What are common causes of early IUGR?

Early IUGR is often caused by poor maternal nutrition, chromosomal abnormalities, and teratogen exposure

What are common causes of late IUGR?

Late IUGR is often caused by placental or maternal complications that impact oxygen or nutrient delivery to the fetus

List some risk factors for IUGR/SGA

Low socioeconomic status (SES)

High parity

Smoking

Drug use

Malnutrition

Lack of prenatal care

Poor personal and sexual hygiene

Small maternal stature

How is being born SGA associated with medical costs?

Being born SGA is associated with higher medical costs due to increased complications at birth, more frequent hospital readmissions, and a longer hospital stay

How do medical costs compare between SGA and non-SGA births?

SGA births cost 2 times more than non-SGA births

How does prematurity and low birth weight affect medical costs in SGA infants?

If an SGA infant is also premature and under 2500 g, medical costs can be up to 11 times higher compared to appropriate-for-gestational-age counterparts

How many SGA infants are born worldwide each year?

Approximately 30 million SGA infants are born worldwide each year

What is the SGA birth rate in Canada?

The SGA birth rate in Canada is 8.9%

Which Canadian provinces have the highest SGA birth rates?

Ontario has the highest SGA birth rate at 8.9%, followed by Alberta at 8.7%

How do SGA birth rates compare between urban and rural areas in Canada?

SGA birth rates are higher in urban areas (8.7%) compared to rural areas (7.0%)

What is catch-up growth in SGA infants?

Catch-up growth is the accelerated growth pattern seen in SGA infants after birth

When does catch-up growth typically occur in SGA infants?

Catch-up growth usually occurs between 6 months and 2 years of age

What percentage of SGA infants achieve catch-up growth by age 2?

About 85% of SGA infants achieve catch-up growth by age 2

How is catch-up growth defined? (3 parameters)

Growth crossing at least one percentile band on a standardized growth chart (Fenton for preterm, WHO for term infants)

An increase in weight-for-age (WFA) z-score of more than 1.0

An equivalent increase in weight standard deviations (SD) of more than 0.67

How does catch-up growth impact neurodevelopment?

Catch-up growth is positively associated with improved neurodevelopmental and cognitive abilities

What are the risks of rapid or excessive catch-up growth in SGA infants?

Rapid or excessive catch-up growth is associated with increased adiposity and a higher risk of metabolic syndrome, type 2 diabetes, obesity, and cardiovascular disease later in life

What is the recommended growth rate for preterm SGA infants?

The recommended growth rate for preterm SGA infants should approximate in utero growth, around 15-20 g/day, requiring 110-135 kcal/kg plus additional energy for catch-up growth

How does gestational age at birth influence catch-up growth?

Lower gestational age at birth is associated with a longer time to achieve catch-up growth

What defines optimal catch-up growth?

Optimal catch-up growth includes an increase in linear growth along with increases in lean body mass

What characterizes sub-optimal catch-up growth?

Sub-optimal catch-up growth is marked by non-proportional increases with excessive fat mass and central adiposity

For which high-risk infant groups are the benefits of breastfeeding most pronounced?

The benefits of breastfeeding are more pronounced for premature infants (<37 weeks gestation) and low birth weight infants (<2500 g)

How does breastfeeding impact morbidity and mortality in high-risk infants?

Reducing the incidence and severity of NEC (necrotizing enterocolitis) and sepsis

Lowering rates of illness and rehospitalization in the first year of life

Improving neurodevelopmental outcomes

What is the initial fluid requirement for infants based on birth weight?

Infants >2000 g: 60 mL/kg on day 1

Infants <2000 g: 80 mL/kg on day 1

Fluids increase to 160-200 mL/kg/day

How are fluid requirements calculated for infants weighing 1-10 kg?

Fluid requirements are calculated as 100 mL/kg for infants weighing 1-10 kg.

What is the starting fluid amount for preterm infants?

Preterm infants should start with 60 mL/kg

How do fluid needs differ between term and preterm infants?

Term infants require at least 100 mL/kg.

This amount is too high for most preterm infants, who start at 60 mL/kg.

Many preterm infants cannot meet the minimum total parenteral intake (TPI), requiring a balance between increasing enteral feeds and reducing total parenteral nutrition (TPN)

What are the energy requirements for SGA babies?

110-135 kcal/kg/d

What is the recommended protein intake for infants?

The recommended protein intake is 3.0-3.6 g/kg/day, providing 12-15 kcal/kg/day or 9%-13% of total calories

What is the recommended protein-to-energy (P:E) ratio for infants?

The recommended P:E ratio is 2.2-3.3 g per 100 kcal

What is a multivitamin recommended for SGA infants?

When they are being breat fed

What is the recommended iron supplementation for infants?

Supplementation with 2 mg/kg/day starting at 8 weeks and continuing until 1 year or until iron-fortified foods are introduced

What type of supplementation is recommended besides iron?

The use of a liquid multiple micronutrient mixture