Findings that show that folate intake before and during pregnancy does not protect Norwegian women against spontaneous preterm delivery are due to be presented at the Society for Maternal-Fetal Medicine's (SMFM) annual meeting, The Pregnancy Meeting , in San Francisco.
"Sufficient folate intake has been studied as a possible protecting factor against spontaneous preterm delivery with conflicting results," said Verena Senpiel, M.D., one of the study's authors. "Preterm delivery is the major cause of perinatal mortality and morbidity worldwide and still difficult to predict and prevent. So when a recent American study found that preconceptional folate supplementation could reduce the risk for early spontaneous preterm delivery 50-70% we hoped to confirm these findings in another big cohort study."
The study selected controls and cases from the Norwegian Mother and Child Cohort Study (http://www.fhi.no/) that included 72,989 children. Cases were defined as singleton live births with spontaneous onset of preterm delivery between 22 and 36 gestational weeks and after pregnancies without medical or obstetric complications. Controls were chosen according to the same criteria, except spontaneous onset of term delivery between gestational weeks 39 and 40. Folate data was obtained from questionnaires completed at gestational week 17, 22 and 30, including a semi-quantitative food frequency questionnaire in the second trimester (week 22).
A total of 955 cases of spontaneous preterm delivery and 18,075 controls were identified. No significant association between gestational age at delivery and the amount of dietary or supplementary folate intake was found. Start of folate supplementation was not significantly related to spontaneous preterm delivery. After dividing women into groups of high or low dietary folate intake, no significant association between folate supplementation and spontaneous preterm delivery was found in either group. Nor was folate supplementation duration significantly related to spontaneous preterm delivery.
The study, one of the most comprehensive on this topic, showed no protective effect of folate intake against spontaneous preterm delivery.