The document discusses the classification and causes of intrauterine growth restriction (IUGR), which is divided into type 1 (symmetrical) and type 2 (asymmetrical) based on the timing of growth inhibition. Type 1 is linked to early pregnancy issues resulting in reduced cell numbers, while type 2 is associated with nutrient supply restrictions and maternal diseases. It also highlights that IUGR can stem from fetal, maternal, and placental disorders, with detailed examples of causes in each category.

1. BY:

3. Classification of Intrauterine Growth
Restriction
1. Type 1 or or IUGR
2. Type 2 or l IUGR
IUGR

4. Type 1 or symmetrical IUGR- (20-
30%)
Occurs as a result of growth inhibition early in
pregnancy i.e. the hyperplastic stage. Any
pathological insult at this phase leads to reduced
no. of cells in fetus and overall decreased growth
potential.
Causes include-
 Intrauterine infections (TORCH )
Chromosomal disorders
Congenital malformations

5. Type 2 or asymmetric IUGR (70-80%)
Occurs as a result of restriction of nutrient supply in
utero i.e. uteroplacental insufficiency.
It is usually associated with maternal diseases
like:-
– Chronic hypertension
– Renal disease
– Vasculopathies

6. Intermediate IUGR (5-10% of all
growth restricted fetuses)
• It is a combination of type 1 and type 2.
• Fetal growth restriction occurs during
intermediate phase of growth affecting both
hyperplasia and hypertrophy, resulting in
decrease in cell no. as well as size.
• Causes include
Chronic HT
Lupus nephritis

7. Etiology
• IUGR is a manifestation of fetal, maternal and
placental disorders that affect fetal growth.
A. Fetal Causes
1. Chromosomal Disorders-usually
result in early onset IUGR.
 Trisomies 13, 18, 21 contribute to 5% of IUGR cases
 Sex chromosome disorders are frequently lethal, fetuses
that survive may have growth restriction (Turner
Syndrome)

8. 2. Congenital Infections:
• The growth potential of fetus may be severely impaired by
intrauterine infections.
• The timing of infection is crucial as the resultant effects
depends on the phase of organogenesis.
• Viruses- rubella, CMV, varicella and HIV
• Protozoa- like malaria, toxoplasma, trypanosoma have also
been associated with growth restriction.
3. Structural Anomalies-
All major structural defects involving CNS,CVS,GIT,
Genitourinary and musculoskeletal system are associated
with increased risk of fetal growth restriction.

9. 4. Genetic Causes-
Maternal genes have greater influence on
fetal growth.
Inborn errors of metabolism like agenesis
of pancreas, congenital lipodystrophy,
galactosemia, phenylketonuria also result in
growth restriction of fetus.
5. Multiple pregnancy

10. B. Placental causes
• Placenta is the sole channel for nutrition and
oxygen supply to the fetus.
Placenta Praevia
Abruptio placentae
Single umbilical artery
Velamentous umbilical cord insertion.
Placental infarction(Thrombophilias)
Placental haemangiomas have all been associated
with fetal growth restriction

11. C. Maternal Causes
1. Maternal Characteristics:
those contributing to IUGR are-
 Extremes of maternal age
 Grand multiparity
 History of IUGR in previous pregnancy
 Low maternal weight gain in pregnancy

12. 2. Maternal diseases:
Uteroplacental insufficiency resulting from
medical complications like
 Hypertension
 Renal disease
 Autoimmune disease
 Hyperthyroidism
 Long term insulin dependent diabetes
3. Toxins: Smoking(Nicotine)
Alcohol, cocaine,opiates, warfarin