[Prevention of the first occurrence of anencephaly and spina bifida with periconceptional multivitamin supplementation (conclusion)].

The risk of recurrent neural-tube defect was decreased in women who took folic acid or multivitamin containing folic acid during the periconceptional period. The extent to which such supplementation can reduce the first occurrence of defects is not known. A randomized, controlled trial of periconcepctional multivitamin supplementation to test the efficacy of this treatment in reducing the incidence of a first occurrence of neural-tube defects was conducted. Women planning a pregnancy (in most cases their first) were randomly assigned to receive a single tablet of a multivitamin supplement (containing 12 vitamins, including 0.8 mg of folic acid; 4 minerals; and 3 trace elements) or a trace-element supplement (containing copper, manganese, zinc, and a very low dose of vitamin C) daily for at least one month before conception and until the date of the second missed menstrual period or later. Pregnancy was confirmed in 5502 women. The outcomes of the informative offspring (whether the fetus or infant had a neural-tube defect or other congenital abnormality) was known in 2471 women who received the multivitamin supplement and in 2391 who received the trace-element supplement. There were six offspring of neural-tube defects in the group receiving the trace-element supplement, as compared with none in the multivitamin-supplement group (p = 0.0014). Congenital abnormalities were significantly more prevalent in the group receiving the trace-element supplement than in the multivitamin-supplement group (2.22 per 1009 vs 1.25 per 1009, p = 0.002).