Prognosis and long-term outcome of IUGR.
A. Mortality:
- Mortality ↑ with decreasing gestational age when FGR is also present.
- Mortality ↓ by 48% for each week that the fetus remains in utero before 30 weeks’ gestation.
B. Postnatal Growth Impairment:
- usually, Term SGA have adequate catch-up growth during the first 12 months without pharmacologic intervention and in most cases catch-up growth is complete by two years.
- However, it is having been suggested that SGA children aged 2−4 years with no evidence of catch-up growth and heights less than –2.5 SD should be referred for endocrine evaluation and eligibility for growth hormone (GH) treatment [for a minority, growth hormone therapy (started before 8 years of age and continued for >7 years) can augment growth parameters.
- Preterm SGA infants can take 4 or more years to achieve heights in a normal range.
- Many preterm infants show a postnatal growth deficit at the time of hospital discharge, so-called extrauterine growth restriction (EUGR), which is defined as a centile at discharge lower than the birth centile.
- EUGR is largely due to an inadequate postnatal nutrient intake as well as postnatal morbidities, and it ↑ with decreased gestational age.
- Premature infants with EUGR also have metabolic abnormalities similar to those observed in term SGA children and these occur irrespectively of whether they are SGA or AGA at birth.
- SGA term infants suffer from an adverse fetal environment during the last trimester of pregnancy, whereas very preterm infants suffer from an adverse postnatal environment during the first three months, a time biologically equivalent to the third trimester of fetal life.
C. Neurological and developmental delay
- Neurodevelopmental morbidities are seen 5 to 10 times more often in FGR infants compared with AGA infants and depend not only on the cause of FGR but also on the adverse events in the neonatal course (eg, perinatal depression or hypoglycemia).
- Even without identified perinatal events, IUGR infants have a higher incidence of long-term neurologic or developmental handicaps.
- Many studies reveal evidence of minimal brain dysfunction, including hyperactivity, short attention span, and learning problems.
- Preterm FGR infants also show alterations in early neurobehavioral functions, such as attention-interaction capacity and cognitive and memory dysfunction, that persist.
- Increased risk of cerebral palsy, a wide spectrum of learning disabilities, mental retardation, developmental delay, and neuropsychiatric disorders are seen in later years.
- The most important predictor of subnormal performance is the absence of catch-up growth in height and/or head circumference.
- Long-term exclusive breastfeeding could help to prevent some of the neurological sequelae of being born SGA. Overfeeding with an enriched formula could accelerate growth, but it does not seem to lead to an advantage for intellectual development and could increase metabolic and cardiovascular risks.
D. Metabolic Risk:
Epidemiologic evidence indicates that obesity, type 2 diabetes, hypertension, dyslipidemia and cardiovascular diseases are more common among adults who were FGR at birth.
E. Chronic Kidney Disease:
When intrauterine resources are restricted, renal development is impaired, possibly at the expense of appropriate development of the brain and heart. The result of this trade-off during organogenesis is a diminished number of nephrons (“nephron underdosing”), predisposing these subjects to albuminuria and to the risk of chronic kidney disease and hypertension. Metabolic syndrome and type 2 diabetes may also cause renal complications.
F. Puberty and Reproductive Function:
˗ Girls born SGA have an increased risk of earlier pubertal development or normal timing with rapid progression.
˗ By contrast, most boys born SGA have normal pubertal timing, but are often short.
G. Others:
- Infants with symmetric FGR caused by decreased growth potential generally have a poor outcome.
- FGR infants with major chromosomal disorders have a 100% incidence of disability.
- Infants with congenital rubella or cytomegalovirus infection with microcephaly have a poor outcome, with a disability rate >50%.
Long Term Follow-Up
· Adequate nutrition.
· Timely immunization.
· Developmental assessment with each routine visit.
· Early referral for developmental intervention and special educational programs.
· Maternal counseling for future conception is important; this is because IUGR commonly recurs. Specific recommendations include:
˗ The mother should be cared for by personnel experienced in handling high-risk pregnancies.
˗ The health of mother and fetus should be assessed throughout pregnancy by ultrasonography and non-stress tests.
˗ Early delivery should be considered if fetal growth is poor.
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