In fetal growth retardation - Etiology

In about 40% of IUGR cases can not be identified. Whenindendificate, these causes can be grouped into four categories:
- Maternal;
- Placenta;
- Fetal;
- The environment.
 
1. Maternal factors.
 
Have 25-30% of all aetiological factors. In this category are citedthe following case:
- Hipostenic constitutional type;
- Reduced overweight (in pregnancy);
- IUGR history (increased risk of repetition);
- Pregnancy-associated hypertension (especially chronic);
- Diabetic vasculopathy, chronic nephropathies;
- Hypotension (native) posture.

2. factors plancentari

- Placenta praevia, accretive circumvallata (even in the absence ofbleeding, placenta praevia transfer function is impaired);
- Placental insufficiency in prolonged pregnancy (placental weightloss and functional impairment);
- Corioangioamele, infarction;
- Abnormal cord insertion (marginal velamentoasa);
- Single umbilical artery.

3. fetal factors

- Chromosomal abnormalities (Turner syndrome, trisomy 13, 18,21) explains up to 15% of all cases of IUGR;
- Intrauterine infections (herpes, cytomegalovirus, rubella,toxoplasma, listeria, Treponema, TB, hepatitis) have up to 10% of the etiology of IUGR;
- Birth defects (brain, heart, gastrointestinal);
- Multiple pregnancy (induced decrease in placental weight inrelation to fetal weight).

4. Environmental factors

- Severe maternal malnutrition: protein restriction produced beforethe 26th week can cause symmetrical IUGR, inadequatecarbohydrate intake can be also a factor etilologic, deficiencies inzinc have been important in relation to impaired fetal growth;
- Smoking (work by reducing uterine blood flow);
- Alcoholism (depending on the amount ingested);
- Drug use (cocaine, fentoina).