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Premature babies and small for gestational age (SGA) babies are more prone to the ailments that can affect all newborn infants because many of their physiological systems are not yet fully developed. Many of these problems are neither life-threatening nor have long-term sequelae. However, some of them can also develop into a severe condition if not treated effectively and promptly.
Small babies, both premature and SGA, are at risk of complications, both during the neonatal period and long-term. There is a separate article on Premature Babies and their Problems. This article will therefore mainly deal with SGA infants.
The risk of perinatal and long-term complications for SGA babies will depend on whether the baby is constitutionally small, small as a result of intrauterine growth restriction (IUGR), or small as a result of a specific underlying cause such as intrauterine infection or chromosome abnormality. See the separate Small for Gestational Age Babies and Intrauterine Growth Restriction articles for further information.
Neonatal presentation of intrauterine growth restriction
The clinical features of IUGR will depend on the underlying cause and whether the IUGR is predominantly symmetrical or asymmetrical. See separate Intrauterine Growth Restriction article for more information.
The clinical features at birth associated with IUGR include:
- Large head when compared to the rest of the body (brain sparing effect).
- Large and wide anterior fontanelle.
- Anxious and hyper-alert infant.
- Absence of buccal fat (old man look).
- Long fingernails.
- Loose, dry and easy peelable skin.
- Loose fold of skin in the nape of the neck, axilla, interscapular area and gluteal region.
- Poor skeletal muscle mass and subcutaneous fat with thin arms and legs.
- Small or scaphoid abdomen.
- Poor breast bud formation and immature female genitalia.
- Relatively large and thin hands and legs compared with the body.
- Thin umbilical cord, often stained with meconium.
Perinatal complications associated with intrauterine growth restriction
IUGR neonates are prone to perinatal complications, including perinatal asphyxia, meconium aspiration, persistent pulmonary hypertension, hypothermia, hypoglycaemia, hyperglycaemia, hypocalcaemia, polycythaemia, jaundice, feeding difficulties, feed intolerance, necrotising enterocolitis, late-onset sepsis and pulmonary haemorrhage.
- Birth/perinatal asphyxia.
- Meconium aspiration.
- Retinopathy of prematurity.
- Persistent pulmonary hypertension.
- Pulmonary haemorrhage.
- Feed intolerance, necrotising enterocolitis.
- Polycythaemia, hyperviscosity.
- Renal dysfunction.
- Hypoglycaemia, hyperglycaemia, hypocalcaemia, low serum ferritin.
Long term complications of small for gestational age babies
SGA children are at higher risk of attaining an adult height below their target height, as well as of developing metabolic disorders (obesity, metabolic syndrome, type 2 diabetes) and cardiovascular diseases. These children are also prone to have precocious pubarche, exaggerated precocious adrenarche, an earlier onset of menarche, and faster progression of puberty than children born appropriate for gestational age.
SGA infants have an increased risk of poorer neurodevelopmental outcomes compared to being appropriate for gestational age.
- Lower scores on cognitive testing.
- Difficulties in schools or requiring special education.
- Gross motor and minor neurological dysfunction.
- Behavioural problems (attention deficit hyperactivity disorder).
- Lower strength and work capacity.
- Cerebral palsy.
- Low social competence.
- Poor academic performance.
- Lower levels of intelligence.
- Hyperactive behaviour.
- Poor perceptual performance.
- Poor visuo-motor perception; motor incompetence and difficulties with reading and with learning mathematics.
Increased risk of other long term complications
- Growth failure
- Cardiovascular disease.
- Obesity, metabolic syndrome, type 2 diabetes mellitus.
- Kidney disease, liver disease.
- Lung abnormalities: reactive airways disease.
- Cancer: breast, ovarian, colon, lung, blood.
- Alzheimer's disease.
- Polycystic ovary syndrome, premature pubarche.
- Shortened lifespan.
- Depression, anxiety, bipolar disorder.
- Immune dysfunction.
- Social problems.
Further reading and references
The Investigation and Management of the Small-for-Gestational-Age Fetus; Royal College of Obstetricians and Gynaecologists Green-top guideline (Mar 2013)
Postnatal care up to 8 weeks after birth; NICE Clinical Guideline (December 2014, updated February 2015)
Sharma D, Shastri S, Sharma P; Intrauterine Growth Restriction: Antenatal and Postnatal Aspects. Clin Med Insights Pediatr. 2016 Jul 1410:67-83. doi: 10.4137/CMPed.S40070. eCollection 2016.
Yadav S, Rustogi D; Small for gestational age: growth and puberty issues. Indian Pediatr. 2015 Feb52(2):135-40.
Arcangeli T, Thilaganathan B, Hooper R, et al; Neurodevelopmental delay in small babies at term: a systematic review. Ultrasound Obstet Gynecol. 2012 Sep40(3):267-75. doi: 10.1002/uog.11112. Epub 2012 Aug 7.