Study: Probiotics may Protect against Preeclampsia and Premature Birth
Oslo – Regular consumption of probiotic milk, which is very popular among pregnant women in Norway, has reduced the rate of preeclampsia and possibly also premature births in a prospective observational study in BMJ Open (2018; 8: e018021).
Many Norwegians drink milk enriched with Lactobacillus acidophilus (LA-5), Bifidobacterium lactis (Bb12) and/or Lactobacillus rhamnosus GG (LGG). The advertising messages of the leading manufacturer Tine are apparently well received by the population. About a quarter of the women who participated in the “Norwegian Mother and Child Cohort Study” (MoBa) stated in a questionnaire that they had regularly drunk a glass of probiotic milk even before pregnancy.
During pregnancy, the proportion initially rose to 37 percent. In late pregnancy, 32 percent of women still regularly drank probiotic milk. The average consumption was one and a half glasses, which corresponds to about 390 ml.
Protective Effect Recognizable
Epidemiologists at the Folkehelseinstituttet in Oslo had already linked the consumption of probiotic milk to a reduced rate of preeclampsia and premature births in two earlier studies. Based on 18,000 and 33,000 women, a protective effect had been recognizable for both diseases. In the meantime, the number of participants has risen to over 70,000, which prompted Mahsa Nordqvist and colleagues to repeat the study.
Of the 37,050 women included in the preeclampsia analysis, 1,851 or 5 percent developed the pregnancy complication. In 550 cases, there was a severe course with severe symptoms, an increase in blood pressure to over 160/110 mm Hg, a proteinuria of more than 3 g/24 hours, possibly also a HELLP syndrome. Among the women who regularly drank probiotic milk in late pregnancy, preeclampsia occurred 20 percent less often (O
The influence on premature birth was less clear. Of the 34,458 women included in the analysis, 2,858 suffered a premature birth. Among them were 1,795 spontaneous premature births and 1,065 medically induced premature births. A relationship to probiotic milk could only be established for consumption in early pregnancy, which, as expected, was only significant for spontaneous premature births (Odds Ratio 0.74; 0.57-0.96).
No Dose-Response Relationship
The study does not provide proof that probiotics protect against preeclampsia and premature birth. As with all prospective studies, it cannot be ruled out that other factors, such as an overall healthier lifestyle of probiotic consumers, are responsible for the protective effect. A weakness is that no dose-response relationship could be demonstrated.
If pregnant women who drank more glasses per day were less likely to get sick, this would have indicated a possible causality. The pathophysiological relationships are also not necessarily plausible. Nordqvist suspects that the consumption of probiotic milk weakens the inflammatory parameters in the blood via the immune system in the intestine and thus possibly prevents the development of preeclampsia and premature birth. However, this is an unproven hypothesis. The researchers also provide no further evidence of a beneficial effect of probiotic milk on the immune parameters in the blood.
Proof of a protective effect could only be provided by a randomized controlled study that would randomly assign women to take probiotics or a placebo. Despite the popularity of probiotic milk in the Norwegian population, such a study is not currently in sight. © rme/aerzteblatt.de