Fetus neural tube defects

The monitoring of pregnancies for neural tube defects Is the most recent of the Indications for prenatal diagnosis In families In which one child has been affected, the risk of recurrence Is approximately 4% Of the 16 pregnancies In which amniocentesis was done to determine the level of a-fetoprotein, no affected fetuses were found ... 

Folate deficiency The recommended dietary intake of folate has been increased (also protects against neural tube defects in the fetus), and additional folate is now added to flour (bread, pasta, and other products made liom flour)... 

Risk factors for deficiency Pregnancy (neural tube defects in fetus may result) Alcoholism Severe malnutrition Risk fiictors for deficiency Pernicious anemia Gastric resection Chronic pancreatitis Severe malnutrition Vegan Infection with D. latum... 

A small sample of amniotic fluid (10-20 ml) is collected at approximately 16 weeks gestation. Fetal cells are present in the amniotic fluid and can be used to diagnose single-gene disorders, chromosome abnormalities, and some biochemical disorders. Elevated a-fetoprotein levels indicate a fetus with a neural tube defect. The risk of fetal demise because of amniocentesis is estimated to be approximately 1/200. 

Although low risks of teratogenesis, including risk of neural tube defects have been reported for several antiepileptics it should be realized that uncontrolled epilepsy poses far more risks for the fetus. 

Because both drugs may interfere with folic acid metabolism, their use during pregnancy is usually contraindicated by the potential for effects on the fetus, such as the development of neural tube defects associated with folate deficiency. The use of trimethoprim is contraindicated in patients with blood dyscrasias, hepatic damage, and renal impairment. 

Women of childbearing age exposed to this agent should be counseled as to its possible teratogenic effects. One percent to 2% of fetuses exposed to VPA in the first trimester have developed neural tube defects and 1% spina bifida (77, 361,362 and 363). 

Valproate, carbamazepine, and other anticonvulsants pose teratogenic risks. Despite this, treatment should continue during pregnancy, as the potential threat to the fetus by a seizure is greater. However, it is mandatory to apply the lowest dose affording safe and effective prophylaxis. Concurrent high-dose administration of folate may prevent neural tube defects. 

Possibly beneficial effects of intakes more than adequate to meet requirements the promotion of optimumhealth and life expectancy. There is evidence that relatively high intakes of vitamin E and possibly other antioxidant nutrients (Section 4.6.2) may reduce the risk of developing cardiovascular disease and some forms of cancer. High intake of folate during early pregnancy reduces the risk of neural tube defects in the fetus (Section 10.9.4). 

Teratogenic effects in developing fetuses such as neural tube defects may occur with valproate use... 

High doses of folic acid can mask signs of B12 deficiency, which is a risk in elderly people. Patients taking phenytoin (Dilantin) for seizures should be cautious about taking folic acid because it can increase the risk of seizures. During the first trimester of pregnancy, folic acid deficiency can affect the development of the central nervous system (CNS) of the fetus this can lead to neural tube defects (NTDs) such as spina bifida, a defective closure of the bony structure of the spinal cord, or anencephaly, lack of brain mass formation... 

D. The fetus needs a constant supply of cofactors for normal development. Folic acid supplements of 400 pg/day prior to conception have been shown to decrease the incidence of neural tube defects such as spina bifida. 

Elevated concentrations of alpha fetoprotein in maternal blood and amniotic fluid may indicate the presence of a fetus with a neural tube defect. 

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