Predetermining Factors
Not all fetuses that are SGA are pathologically growth restricted and, in fact, may be constitutionally small.
The risk factors for and etiologies of pathological SGA can be broadly divided into 3 categories-
- Fetal
- Maternal
- Placental
The primary risk factor is that development of the placenta is insufficient to meet the demands of the fetus, resulting in malnutrition of the developing fetus. There are numerous contributing factors of both environmental and genetic origin:
- Environmental factors such as poor nutrition, maternal tobacco smoking, drug addiction or alcoholism
- Severe anaemia (although hydrops may also occur)
- Thrombophilia (tendency for thrombosis)
- Prolonged pregnancy
- Pre-eclampsia
- Chromosomal abnormalities
- Diabetes Mellitus
- Connective Tissue Disease/Disorders (Systemic Lupus Erythematosis), Ehlers-Danlos Syndrome
- Damaged or reduced placental tissue due to:
- Chronic renal failure
- Sickle cell anemia
- Phenylketonuria
- Infections such as rubella, cytomegalovirus, toxoplasmosis or syphilis
- Twins and multiple births.
Read more about this topic: Small For Gestational Age
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