Exposure to vitamin D from fortified margarine during fetal life and later risk of pre-eclampsia: the D-tect Study

To examine if fetal exposure to a small dosage of extra vitamin D from food fortification was associated with a decrease in the risk of pre-eclampsia later in life.

Cancellation of the mandatory vitamin D fortification of margarine in 1985 created a societal experiment, with entire adjacent birth cohorts exposed or unexposed to extra vitamin D during fetal development. The Danish national medical health registries allowed the identification of pre-eclampsia cases later in life among all exposed and unexposed female individuals.

Denmark.

Women born between June 1983 and August 1988, who gave birth to their first child at age 14·5-27·5 years (n 32 621).

OR (95 % CI) for pre-eclampsia among women exposed v. unexposed to extra vitamin D from fortification during fetal development was 0·86 (0·76, 0·97). Exposure to extra vitamin D was associated with further reduced odds of pre-eclampsia (0·49 (0·34, 0·72)) among current smokers, but not among former smokers and non-smokers.

Additional vitamin D in fetal life from food fortification seems to reduce the risk of pre-eclampsia later in life. The risk reduction may be particularly strong among women who smoke during pregnancy.