Folic acid and prevention of neural tube defects: a study of Canadian mothers of infants with spina bifida.

OBJECTIVES

To determine the diffusion of information about preventing neural tube defects (NTDs) through folic acid consumption by examining whether mothers of Canadian children born with spina bifida, who had become pregnant at least a year after evidence of the preventive effect of folic acid had been published, had taken sufficient amounts of folic acid in the periconceptional period and were aware of this important new information.

DESIGN

Validated food-frequency questionnaire to assess folate intake.

SETTING

The Hospital for Sick Children in Toronto between Jan. 4 and Aug. 16, 1994.

PARTICIPANTS

Thirty mothers whose infants were being treated for spina bifida.

MAIN OUTCOME MEASURES

The mothers' mean folate intake and knowledge about the protective effect of folic acid; demographic and health information.

RESULTS

The mothers' mean folate intake was 0.182 mg/d (standard deviation 0.076 mg/d, range 0.02 to 0.53 mg/d), less than half the protective dose. Only 4 (13%) of the mothers had been aware of the relation between nutritional folate and NTDs when they conceived, but even they did not supplement their diets with sufficient folic acid. The medical data showed that, in addition to the failure of primary prevention of NTDs, secondary prevention through diagnostic tests during pregnancy were also inadequate.

CONCLUSIONS

Our study, one of the first to be conducted after the role of folate in preventing NTDs was confirmed, reveals that, in one of the most advanced countries in the world, this new information has had no effect on patients' folate intake. Unless food is fortified with folate, the estimated 400 to 800 annual cases of NTDs in Canada will not be prevented.