Regular use of multivitamin supplements before and around conception may reduce the risk of pre-eclampsia in pregnancy, a new study has found.

Pre-eclampsia is a form of high blood pressure in pregnancy that is caused by a problem with the placenta. If pre-eclampsia is not detected, the results can be dangerous for both mother and baby.

This new study looked at the records of over 28,000 women who were recruited to the Danish National Birth Cohort. These records reported the number of cases of pre-eclampsia, as well as the number of women who took regular multivitamin supplements from 4 weeks prior to 8 weeks after conception).

Overall, 668 cases of pre-eclampsia were recorded, and 18.551 women reported regular multivitamin use. When the researchers analysed these figures, they found that in women who were no overweight, regular multivitamin use reduced their pre-eclampsia risk by 20%.

Even women who only began taking multivitamins after conception appeared to benefit from a reduced pre-eclampsia risk. Again, this only applied to women who were not overweight.

It is not known for certain whether multivitamins directly reduce the risk of pre-eclampsia. It may be that women who take multivitamins around conception are also less likely to have other risk factors for pre-eclampsia, such as overweight or existing high blood pressure. More research will need to be done to establish whether the multivitamins directly protect women.

If you are pregnant or are planning a pregnancy, you should discuss taking multivitamins with your doctor.

American Journal of Epidemiology 2009; 169:1304-1311