Probiotics in pregnancy: Protocol of a double-blind randomized controlled pilot trial for pregnant women with depression and anxiety (PIP pilot trial)

Pamela D. Browne*, Antoinette Bolte, Eric Claassen, Carolina De Weerth

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review


Background: Maternal prenatal depressive or anxiety symptoms are associated with adverse maternal and infant health outcomes. With prevalence rates of maternal prenatal depression and anxiety ranging between 10 and 20%, attempts to identify effective interventions to reduce symptoms are priority. There are indications that probiotics can reduce symptoms of maternal depression or anxiety. Probiotics ingested by the mother may thus offer a promising and accessible intervention to complement existing treatments. Methods: The Probiotics in Pregnancy (PIP) pilot trial is a double-blind, placebo-controlled, randomized pilot trial. While one group orally consumes a probiotic mixture (Ecologic® Barrier; 2,5 × 109 colony forming units/g; 2 g; daily), the other group consumes a placebo, from between 26 and 30 weeks gestation until delivery. Subjects are randomly allocated (1:1) to the intervention or placebo group. Forty healthy pregnant women with symptoms of depression or anxiety and uncomplicated pregnancies at randomization will be included. The primary aim is to determine the feasibility and acceptability of a probiotic trial to reduce symptoms of maternal depression or anxiety in pregnancy. The secondary aim is to exploratorily compare the potential effect of probiotics, compared to placebo, on depressive and/or anxiety symptoms, maternal stress (i.e. reported/hair cortisol), maternal vaginal and intestinal microbiota, and by possibly affecting maternal mood and microbiota, maternal bonding to offspring, infant microbiota and infant crying. Discussion: Results of this pilot trial will help determine whether or not to proceed with a full trial after the pilot trial, and if so, whether revisions should be made to the study protocol and procedures before conducting a full randomized controlled trial. Additionally, they are expected to provide insights into whether changes in psychological, behavioral and biological parameters can be attributed to the probiotic intervention. Trial registration: Netherlands Trial Register, NTR6219. Registered on 28 February 2017.

Original languageEnglish
Article number440
Pages (from-to)1-21
Number of pages21
Publication statusPublished - 17 Jul 2019


  • Maternal prenatal anxiety and depression
  • Pilot RCT
  • Pregnancy
  • Probiotics


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