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Obstetrics Simplified - Diaa M. EI-Mowafi

Intrauterine Growth Retardation (IUGR) (Dysmaturity or Small-for-Date)


Definition

Infant’s weight less than the tenth percentile of its gestational age.

Aetiology

  • Chromosomal and genetic disorders: e.g.
    • Down’s syndrome.
    • Turner’s syndrome.     
    • Renal agenesis.
  • Intrauterine infections: e.g.
    • Cytomegalovirus.      
    • Rubella.       
    • Syphilis.
  • Maternal factors:
    • Maternal malnutrition: due to,
      • Chronic infections.         
      • Worm infestations.
      • Malabsorption syndrome.
      • Wasting diseases.
    • Narcotic drug addiction.
    • Cigarette smoking.  
    • Exposure to ionising radiation .
    • Maternal anaemia.              
    • Rh-isoimmunization.
  • Uteroplacental vascular insufficiency: due to
    • Maternal hypertension.       
    • Maternal diabetes.
    • Chronic renal disorders.
    • Partial abruptio placentae.
    • Multiple pregnancy.       
    • Post-term pregnancy.

Types

  • Symmetric IUGR:
    • Early stage of IUGR.
    • The growth impairment involves all body structures including the internal organs.
    • It is usually due to chromosomal, genetic or infective causes.
  • Asymmetric IUGR:
    • Late stage of IUGR.
    • The growth impairment involves the body but not the brain tissues "sparing effect", so the head is big in comparison to the body.
    • It is usually due to chronic malnutrition and uteroplacental insufficiency.

Diagnosis

History: of any of the aetiological factors.

Examination may reveal:

  • Poor maternal weight gain or even weight loss during pregnancy.
  • Fundal level is lower than that corresponds to the period of amenorrhoea.
  • Oligohydramnios.
  • Underlying cause may be detected.
  • The neonate shows signs of dysmaturity as:
    • underweight,
    • dry wrinkled skin,
    • meconium stains the foetus, placenta umbilical cord as well as the amniotic fluid.

Investigations

  • Ultrasonography: may show;
    • Smaller biparietal diameter in serial measurements.
    • Smaller abdominal circumference (measured at the level of bifurcation of the portal vein in the liver).
    • Large head/abdominal circumference ratio in case of asymmetric IUGR.
    • Congenital anomalies.
    • Oligohydramnios.
    • Doppler ultrasound: shows increased systolic / diastolic velocity ratio in the umbilical artery due to high resistance in the distal vascular bed in the placenta.
  • Daily foetal movement count:
    • Less than 10 movements / 12 hours.
  • Antenatal cardiotocography:
    • Non -stress test: non -reactive.
    • Stress test: late deceleration.
  • Biophysical profile: see before.
  • Hormonal study: see before.
  • Amnioscopy: meconium stained liquor.

Management

Antenatal

  • Rest in bed in lateral position (better the left) to prevent IVC compression . This increases the placental blood flow by 25%.
  • Smoking should be discouraged.
  • Treatment of the underlying cause.
  • Monitoring of foetal wellbeing.
  • Termination of pregnancy according to the balance between risk of intrauterine asphyxia against those of prematurity.

Intranatal

  • Mode of delivery is influenced by:
    • gestational age,
    • result of the stress test,
    • associated factors as malpresentations, antepartum haemorrhage, previous caesarean section ...etc.
    • Caesarean section is more liberally indicated especially if there are associated adverse factors as the foetus does not tolerate the reduced oxygen supply and birth trauma encountered during vaginal delivery.
  • Continuous intranatal monitoring.

Postnatal

Identification and management of problems of dysmaturity as:

  • Hypothermia: due to relatively large surface area and lack of insulating fat layer
  • Asphyxia neonatorum: as an extension to the intrauterine asphyxia or due to meconium aspiration.
  • Hypoglycaemia: due to increased metabolic demands, especially in presence of chilling and poor glycogen reserves.
  • Hypocalcaemia: manifested by clonus, tremors or convulsions.
  • Haemorrhagic tendency: may cause pulmonary haemorrhage and death.
  • Stunted growth and mental retardation: more liable to occur in the future.

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