Intrauterine growth restriction(IUGR)
The common definition of intrauterine growth restriction (IUGR) (also known as fetal growth restriction) is a fetus with estimated fetal weight (EFW) <5−10 th percentile for gestational age.
Another definition is estimated fetal weight is <2,500 grams.
Causes:
Fetal causes:
1-Chromosomal (Down’s syndrome,Turner’s syndrome)
2-Structural anomalies(Renal agenesis,congenital heart disease, neural tube defects,ventral wall defects)
3-Intrauterine infections(TORCH,Syphilis)
These causes typically lead to symmetric IUGR.
Placental causes:
1-infarction
2-abruption
3-twin-twin transfusion syndrome(TTTS)
4-velamentous cord insertion.
These causes typically lead to asymmetric IUGR.
Maternal causes:
1-Maternal malnutrition(Chronic infections,Worm infestations,Malabsorption syndrome,Wasting diseases)
2-Hypertension,long standing diabetes type 1
3-maternal anemia
4-RH-isoimmunization
5-Alcohol,tabaco,narcotic addiction
These causes typically lead to asymmetric IUGR.
Type of IUGR:
1-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.
- All ultrasound parameters (Head Circumference, Biparietal Diameter, Abdominal Circumference, Fetal diaphesis length) are smaller than expected.
- Workup should include detailed sonogram, karyotype, and screen for fetal infections.
- Antepartum tests are usually normal.
Obestetric triad of symmetric IUGR:
1-Head and abdomen both small
2-Etiology: fetal (aneuploidy, infection, anomaly)
3-Decreased growth potential
2-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.
- Ultrasound parameters show head sparing, but abdomen is small.
- It is usually due to chronic malnutrition and uteroplacental insufficiency.
Obestetric triad of asymmetric IUGR:
1-Head normal; abdomen small.
2-Etiology: maternal-fetal (inadequate nutritional substrates).
3-Decreased placental perfusion.
Diagnosis:
(A)History: of any of the aetiological factor.
(B)Examination: may reveal
1-Poor maternal weight gain or even weight loss during pregnancy.
2-Fundal level is lower than that corresponds to the period of amenorrhoea.
3-Oligohydramnios
4-Underlying cause may be detected.
5-The neonate shows signs of dysmaturity as:
– underweight,
– dry wrinkled skin,
– meconium stains the foetus, placenta umbilical
cord as well as the amniotic fluid.
(C) Investigations:
(1)Ultrasonography: decreased ultrasound parameters,congenital anomalies,oligohydramnios.
(2)Daily foetal movement count: Less than 10 movements / 12 hours.
(3)Antenatal cardiotocography:
-Non -stress test : non -reactive.
-Stress test : late deceleration.
Management:
(a)Antenatal
1-Rest in bed in lateral position ( better the left) to prevent Inferior Venacava compression . This increases the placental blood flow by 25%.
2-Smoking should be discouraged.
3-Treatment of the underlying cause.
4-Monitoring of foetal wellbeing.
5-Termination of pregnancy according to the balance between risk of intrauterine asphyxia against those of prematurity.
(b)Intranatal
1- 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.
2- Continuous intranatal monitoring.
(c)Postnatal
Identification and management of problems of dysmaturity as:
1-Hypothermia: due to relatively large surface area and lack of insulating fat layer
2-Asphyxia neonatorum: as an extension to the intrauterine asphyxia or due to meconium aspiration.
3-Hypoglycaemia: due to increased metabolic demands, especially in presence of chilling and poor glycogen reserves.
4-Hypocalcaemia: manifested by clonus, tremors or convulsions.
5-Haemorrhagic tendency: may cause pulmonary haemorrhage and death.
6-Stunted growth and mental retardation : more liable to occur in the future.