The potential benefits were even more pronounced when the researchers studied severe pre-eclampsia, with daily intakes associated with a 39% reduction, according to results published in the American Journal of Epidemiology.
Pre-eclampsia, affecting two to three per cent of all pregnancies, occurs when a mother's blood pressure rises to the hypertensive range, and excretion of protein in the urine becomes too high. It is estimated to be responsible for about 60,000 deaths worldwide.
It is not known why some expectant mothers develop pre-eclampsia, although oxidative stress and inflammation has been proposed to play a part.
According to the Norwegian researchers, probiotics may confer benefits via two routes: One possibility is a local effect on cells surrounding the embryo (placental trophoblasts), and another possibility is via an overall effect on inflammation levels.
“This large observational study indicates an independent protective association between intake of probiotic milk products and preeclampsia, especially severe preeclampsia, suggesting that probiotics might specifically ‘target’ and modify the type of inflammation underlying severe preeclampsia,” wrote the authors, led by Dr Anne Lise Brantsæter.
“Further strain/species-specific investigation is warranted with the use of randomized controlled trials for further evaluation of the effect of probiotics on preeclampsia.”
The Norwegian researchers analyzed data from 33,399 women participating in the Norwegian Mother and Child Cohort Study.
The intake of lactobacilli-containing milk-based products was determined using a food frequency questionnaire, while pre-eclampsia was determined using the Norwegian Medical Birth Registry.
Results showed that the daily intake of at least 140 mL of probiotic milk products was associated with a 20% reduced risk of pre-eclampsia.
The effects were more pronounced for severe pre-eclampsia, with daily and weekly intakes of probiotic products associated with a 39% and 25%, respectively.
“These results suggest that regular consumption of milk-based probiotics could be associated with lower risk of preeclampsia in primiparous women,” they concluded.
Source: American Journal of Epidemiology
Published online ahead of print, doi:10.1093/aje/kwr168
“Intake of Probiotic Food and Risk of Preeclampsia in Primiparous Women: The Norwegian Mother and Child Cohort Study”
Authors: A.L. Brantsæter, R. Myhre, M. Haugen, S. Myking, V. Sengpiel, P. Magnus, B. Jacobsson, H.M. Meltzer