An interventional study of Kefir in Gestational Diabetes Mellitus (GDM), Blood Glucose and Insulin Resistance, Diabetes, sponsored by University of New Brunswick. Recruiting at 1 site in Canada. Open to female participants aged 19 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-09-28.
Sponsored by University of New Brunswick · Not applicable, Interventional, and Prevention
Pregnancy is a critical window for metabolic health, and early changes in blood sugar regulation can increase the risk of gestational diabetes mellitus (GDM), which affects both maternal and infant health. At the same time, the maternal gut microbiome changes throughout pregnancy and may play a role in glucose metabolism and insulin resistance. Kefir, a fermented milk drink containing beneficial bacteria and yeasts, may be a simple dietary strategy to support metabolic health during pregnancy, but its role in preventing GDM has not been well studied.
This study will test whether drinking kefir daily from mid-pregnancy until routine GDM screening can improve glucose and insulin regulation, reduce the incidence of GDM, and modulate the maternal gut microbiome and metabolites, among other outcomes.
Pregnant individuals will be randomly assigned to either a kefir group or a control group receiving usual prenatal care. Researchers will collect blood glucose and insulin measures, dietary information, stool samples, and body composition data across pregnancy and postpartum to evaluate metabolic and microbiome-related changes.
As one of the first studies to examine kefir as an early pregnancy intervention for GDM prevention, this study will help clarify whether a practical, food-based approach can improve maternal metabolic health. The findings may support future nutrition strategies aimed at reducing GDM risk and improving pregnancy outcomes.
Pregnancy is characterized by progressive metabolic and hormonal changes, including increasing insulin resistance, particularly in the second trimester. At the same time, the maternal gut microbiome undergoes substantial shifts across gestation and may contribute to glucose metabolism, insulin resistance, and inflammation. Dietary strategies that can favorably influence the gut microbiome and metabolic health during pregnancy may represent a promising approach to reduce GDM risk. Kefir, a fermented dairy beverage containing a complex consortium of beneficial bacteria and yeasts, has shown potential for improving glycemic control and modulating the gut microbiome in non-pregnant populations, but its preventive role for GDM has not been well established.
The primary aims of this study are to determine whether daily kefir consumption initiated in mid-pregnancy can improve maternal glucose and insulin regulation. Secondary aims will examine whether kefir consumption reduces the incidence of GDM, beneficially modulates maternal gut microbiome and metabolite profiles, and alters postpartum health measures such as breastmilk composition and infant anthropometrics.
This randomized controlled trial in the PEADS Lab at the University of New Brunswick will assign pregnant participants to either a daily kefir intervention group or a control group receiving usual prenatal care. Participants in the intervention group will consume 250 mL of kefir daily beginning at approximately 14 weeks' gestation and continuing until the routine GDM screening window at 26-28 weeks' gestation. Those in the control group will continue with their usual care and habitual diet, but will be asked not to consume kefir for the duration of the study. Participants will attend study visits across pregnancy and postpartum, during which researchers will collect dietary recalls, anthropometric and body composition measurements, blood pressure, and stool and breastmilk samples. Fasted clinical bloodwork will be used to assess glucose and insulin-related outcomes, including screening for GDM.
The primary outcomes are between-group differences in maternal glycemic and insulinemic measures. Secondary outcomes include the incidence of GDM, changes in gut microbial diversity, composition, and metabolites such as short-chain fatty acid concentrations, maternal body composition, breastmilk composition, and infant anthropometrics. Assessments will occur at baseline (\~14 weeks gestation), at the GDM screening windows (18-20 weeks for high-risk and 26-28 weeks for low-risk), and one month postpartum.
Pregnancy represents a critical opportunity for early prevention of metabolic complications that can affect lifelong maternal and child health. This study is the first to evaluate kefir as a practical, food-based intervention for GDM prevention, while also exploring the role of the gut microbiome as a potential modifiable mechanism. By integrating clinical, dietary, and microbiome data, this trial will help generate evidence to support accessible nutrition strategies that may improve pregnancy outcomes and inform future maternal health recommendations.
877 studies on the registry are indexed under Diabetes, Gestational; 203 are open to participants now.
This study's planned enrollment of 60 is below the median of 110 across 564 interventional studies indexed under Diabetes, Gestational.
Browse Diabetes, Gestational studies →University of New Brunswick is the lead sponsor of 19 studies on the registry; 4 are open to participants now.
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Exclusion Criteria:
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Contraindication
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Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants assigned to this group will consume 250 mL of kefir daily beginning at approximately 14 weeks' gestation through the routine GDM screening window at 26-28 weeks' gestation. Participants will otherwise continue their usual prenatal care and habitual diet.
Dietary Supplement: Kefir
Participants assigned to this group will continue their usual prenatal care and habitual diet beginning at approximately 14 weeks' gestation through the routine GDM screening window at 26-28 weeks' gestation. Participants will not consume the study kefir.
Kefir is a fermented dairy beverage containing a complex host of live bacteria and yeasts. In this study, participants assigned to the intervention group will consume 250 mL of kefir daily from approximately 14 weeks' gestation until the routine GDM screening window at 26-28 weeks' gestation. Participants will otherwise continue their usual prenatal care and habitual diet.
Maternal Fasting Glucose Concentrations
Between-group difference in maternal fasting glucose concentrations measured at baseline (14 weeks' gestation) and during pregnancy via glucose challenge testing conducted within the respective screening window (18-20 weeks' gestation for high-risk or 24-28 weeks' gestation for high-risk and/or low-risk).
Time frame: Baseline, 18-20 weeks' gestation, 26-28 weeks' gestation
Maternal hbA1c Concentrations
Between-group difference in maternal hbA1c concentrations measured at baseline (14 weeks' gestation) and during pregnancy conducted within the respective screening window (18-20 weeks' gestation for high-risk or 24-28 weeks' gestation for high-risk and/or low-risk).
Time frame: Baseline, 18-20 weeks' gestation, 26-28 weeks' gestation
Maternal Fasting Insulin Concentrations
Between-group difference in maternal fasting insulin concentrations measured during pregnancy at the respective screening window (18-20 weeks' gestation for high-risk or 24-28 weeks' gestation for high-risk and/or low-risk).
Time frame: 18-20 weeks' gestation, 26-28 weeks' gestation
Maternal Insulin Area Under the Curve
Between-group difference in maternal insulin area under the curve measured during pregnancy at the respective screening window (18-20 weeks' gestation for high-risk or 24-28 weeks' gestation for high-risk and/or low-risk).
Time frame: 18-20 weeks' gestation, 26-28 weeks' gestation
Maternal Whole-Body Insulin Sensitivity
Between-group difference in maternal whole-body insulin sensitivity measured during pregnancy at the respective screening window (18-20 weeks' gestation for high-risk or 24-28 weeks' gestation for high-risk and/or low-risk).
Time frame: 18-20 weeks' gestation, 26-28 weeks' gestation
Gut Microbiome Diversity and Composition
Gut microbiome diversity and taxa will be assessed using metagenomic sequencing of stool samples collected from participants. Alpha diversity metrics (e.g., Shannon index, Chao1) and beta diversity metrics (Bray-Curtis dissimilarity) will quantify within- and between-sample microbial diversity. Taxonomic composition at phylum, family, and genus levels will be examined.
Time frame: At baseline, 18-20 weeks' gestation, and 26-28 weeks' gestation
Gut Microbiome Metabolites
Microbial metabolite profiles relevant to inflammation and metabolic regulation such as short-chain fatty acids will be examined.
Time frame: At baseline, 18-20 weeks' gestation, and 26-28 weeks' gestation
Maternal Weight
Maternal weight will be measured at each study visit.
Time frame: Baseline, 18-20 weeks' gestation, 26-28 weeks' gestation, 1 month postpartum
Maternal Height
Maternal height will be measured at baseline.
Time frame: Baseline
Maternal Body Composition (BOD POD)
Maternal body composition will be assessed at each visit using air-displacement plethysmography to estimate fat mass and fat-free mass.
Time frame: Baseline, 18-20 weeks' gestation, 26-28 weeks' gestation, 1 month postpartum
Maternal Blood Pressure
Maternal blood pressure will be measured to provide additional information on maternal cardiovascular and metabolic health.
Time frame: Baseline, 18-20 weeks' gestation, 26-28 weeks' gestation, 1 month postpartum
Maternal Breastmilk Composition (Miris HMA)
Breastmilk will be collected 1 month postpartum.
Time frame: 1 month postpartum
Infant Length
Infant length will be assessed using standardized procedures 1 month postpartum.
Time frame: 1 month postpartum
Infant Weight
Infant weight will be assessed using standardized procedures 1 month postpartum.
Time frame: 1 month postpartum
Infant Head and Abdominal Circumferences
Infant circumferences will be assessed using standardized procedures 1 month postpartum.
Time frame: 1 month postpartum
Infant Body Composition
Infant body composition will be assessed using air-displacement plethysmography 1 month postpartum.
Time frame: 1 month postpartum
Dietary intake
Participants will complete the Automated Self-Administered 24-hour dietary assessment tool (ASA-24) at two time points (one weekday and one weekend).
Time frame: Baseline, 18-20 weeks' gestation, 26-28 weeks' gestation, 1 month postpartum
Pregnancy Physical Activity Questionnaire
Participants will complete the Pregnancy Physical Activity Questionnaire (PPAQ).
Time frame: Baseline, 18-20 weeks' gestation, 26-28 weeks' gestation, 1 month postpartum
Postpartum Physical Activity Questionnaire
Participants will complete the Postpartum Physical Activity Questionnaire.
Time frame: 1 month postpartum
Edinburgh Postnatal Depression Scale
Participants will complete the Edinburgh Postnatal Depression Scale (EPDS).
Time frame: Baseline, 18-20 weeks' gestation, 26-28 weeks' gestation, 1 month postpartum
Anxiety subscale of the Symptom Checklist-90
Participants will complete the Anxiety subscale of the Symptom Checklist-90 (SCL-90).
Time frame: Baseline, 18-20 weeks' gestation, 26-28 weeks' gestation, 1 month postpartum
Weight Control Strategies Scale
Participants will complete the Weight Control Strategies Scale (WCSS).
Time frame: Baseline, 18-20 weeks' gestation, 26-28 weeks' gestation, 1 month postpartum
Plan to share: Undecided
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Studies of the drug tested here: Kefir
University of New Brunswick