If you are pregnant and wondering whether it is safe to keep taking probiotics, or to start, the short answer is yes. For healthy individuals, the research consistently confirms probiotic safety during pregnancy. Here is what the evidence says, what clinicians advise, and what Canadian pregnant women specifically should know before choosing a product. Are Probiotics Safe While Pregnant? Yes. A 2018 review of 49 publications found no association between probiotic use during pregnancy and increased risk of preterm birth, miscarriage, or other adverse outcomes in mothers or newborns. A 2020 meta-analysis of 18 RCTs reported a reassuring finding: gestational length was significantly longer in the probiotic group than in the placebo group. The most studied genera, Lactobacillus and Bifidobacterium, are rarely systemically absorbed in healthy individuals. The risk of a probiotic-induced infection is extremely low in people with a healthy immune system and intact gut lining. One important exception: women who are immunocompromised, have a compromised gut barrier, or are managing a complex medical condition should always consult their OB-GYN or midwife before starting any probiotic. For everyone else, the safety record in the published literature is reassuring and consistent. How Pregnancy Changes Your Gut Pregnancy triggers significant physiological changes that affect the gut microbiome from the first trimester onward. Hormonal shifts alter microbial composition, and microbiome diversity naturally decreases as pregnancy progresses, reaching its lowest point in the third trimester. This is a documented pattern specific to pregnancy, not a sign of poor health. A healthy, diverse gut microbiome supports immune function, nutrient absorption, and lower inflammatory markers, all of which are relevant to both maternal and fetal well-being. Dysbiosis during pregnancy has been associated with increased susceptibility to digestive complaints like constipation and bloating, which are already common in this period. A 2020 study of 49 pregnant women found that the probiotic group had significantly higher microbiome diversity and more beneficial bacteria than the placebo group. Probiotic Strains Studied in Pregnancy Not every probiotic strain has been studied in pregnant populations. The evidence base is concentrated in the Lactobacillus and Bifidobacterium genera, and strain specificity matters. Lactobacillus rhamnosus GG is one of the most extensively studied strains in pregnant populations, appearing in RCTs examining infant gut microbiome establishment and early immune development. Lactobacillus rhamnosus HN001 was used in a 2017 RCT beginning at weeks 14 to 16 of pregnancy and continuing through six months postpartum, with results showing significantly lower depression and anxiety scores in mothers compared to placebo. Bifidobacterium lactis BB12 combined with L. rhamnosus GG has also been studied for maternal gut health outcomes. For Canadian readers, a 2025 RCT from Clinique Ovo in Montreal studied Lacticaseibacillus rhamnosus Rosell-11 and Bifidobacterium bifidum HA-132 given from 28 weeks of gestation, representing the most recent Canadian-specific pregnancy probiotic evidence available. When reading a label, look for the full strain name, including the alphanumeric code; a CFU count guaranteed to the expiry date rather than the manufacture date; and clinical evidence specific to the strains listed. When to Start Taking Probiotics There is no single mandated start time. The research shows probiotic use is safe at various stages of pregnancy. What changes by trimester is the practical context. Probiotics in the first trimester Gut microbiome changes begin in the first trimester. Starting a probiotic early establishes a consistent routine from the outset, and published research shows no association between first-trimester probiotic use and miscarriage, malformation, or other adverse outcomes. If morning sickness is significant, a capsule format may be easier to tolerate than a drinkable. Taking probiotics with meals is associated with better bacterial survival in transit. Always let your OB-GYN or midwife know when you add any new supplement in the first trimester. Second-trimester use The second trimester is the most common period for initiating probiotic supplementation in published pregnancy RCTs, including the L. rhamnosus HN001 study, which began at weeks 14 to 16. Gut microbiome shifts accelerate during this stage, and this is when probiotic support for digestive comfort, particularly for constipation, is most relevant. Third trimester and beyond Microbiome diversity reaches its lowest point in the third trimester, making continued probiotic use particularly relevant. The 2025 Clinique Ovo RCT initiated supplementation at 28 weeks, confirming safety and tolerability late in pregnancy. Some research also suggests that probiotic use during delivery may influence the establishment of the infant microbiome in the first days of life. Capsules vs. Drinkables in Pregnancy No competitor addresses this question directly, but it is one that pregnant women genuinely ask. Both formats are safe for use in pregnancy in healthy individuals. The right choice comes down to routine and tolerability. Capsules are convenient, format-stable, and use delayed-release technology to protect bacteria from stomach acid. They are easy to take at a fixed time each day, which supports the consistent daily use recommended by research. Some capsule shells are made of HPMC, making them suitable for vegans. Drinkable probiotics in the Bio-K+ range are produced under controlled fermentation conditions. Dairy-based versions are made from pasteurized milk, which directly addresses the pregnancy food-safety concern about unpasteurized fermented products. Probiotic yogurt during pregnancy is generally considered safe when made from pasteurized milk. The concern is specifically with unpasteurized fermented products, including some home-brewed kombucha and raw-milk cheeses, which carry Listeria risk. Vegan drinkable options fermented from rice, soy, or pea base deliver the same 50 billion CFU count for those avoiding dairy during pregnancy. Safe Probiotic Options in Pregnancy By Bio-K+ At Bio-K+, we bring over 30 years of research and development, supported by 15 clinical trials and more than 40 scientific publications. Our core formula is built around three proprietary strains—Lacticaseibacillus casei LBC80R®, Lacticaseibacillus rhamnosus CLR2®, and Lactobacillus acidophilus CL1285®—designed to support gut and intestinal health. For women’s health, our Women's Health Capsules feature Lactobacillus rhamnosus GR-1™ and Lactobacillus reuteri RC-14™, strains that have been studied for their role in maintaining healthy vaginal flora. These products are available in Canada with approved health claims for vaginal flora support. Our products sold in Canada carry a Natural Product Number (NPN), meaning they have been reviewed by Health Canada for safety, efficacy, and quality. We also guarantee our CFU count until the expiry date, ensuring potency at the time of consumption. If you are pregnant or considering probiotics during pregnancy, we recommend consulting a healthcare professional to determine what is appropriate for your individual needs. What OB-GYNs and RDs Recommend The general clinical consensus is that probiotics are considered safe for use in pregnancy in healthy individuals. No major obstetric body has issued a contraindication against probiotic use during pregnancy. OB-GYNs typically advise you to inform your provider before starting any new supplement, including probiotics. This conversation matters especially in the first trimester and for anyone managing a condition that affects immune function. Registered dietitians advise choosing a product with full strain names listed, CFU guaranteed to the expiry date, and a published clinical evidence base for the specific strains included, not just the genus. For Canadian pregnant women, an NPN number on the label is Health Canada's verification that the product has been reviewed for safety and quality for its indicated use. Probiotics do not replace prenatal vitamins, folic acid, or iron supplementation. They are a complementary addition, not a substitute for the supplements your provider has already recommended. Conclusion The evidence is clear and consistent: probiotic supplementation is safe for healthy pregnant individuals throughout all three trimesters. The Lactobacillus and Bifidobacterium genera have the strongest safety and research record in pregnancy, and Canadian consumers have the added assurance of the NHP and NPN framework through Health Canada. Whether you choose a capsule or drinkable format, what matters most is consistent daily use, full strain transparency on the label, and an open conversation with your OB-GYN or midwife. Gut health during pregnancy is part of a broader picture of maternal well-being, and the right probiotic, chosen thoughtfully, can be a meaningful part of that picture.
