Retraction

This article [1] has been retracted by the authors, as some of the reported data was incorrect. The error concerned approximately 8% of the cohort (women who answered the first version of the food frequency questionnaire, before 2002) and was caused by misclassification of the amount of the women’s reported folic acid supplementation (no supplement use instead of missing information on supplement use). The error led to minor changes in the results.

However, the estimate of the association between folate intake and spontaneous preterm delivery did not change the conclusions after the error was corrected.

In consultation with the Journal’s editors we decided to retract the article from BMC Pregnancy and Childbirth.

A corrected manuscript will be resubmitted to the Journal at the time of retraction.

On behalf of all authors,

Verena Sengpiel and Bo Jacobsson.