"All Disease Begins in the Gut.”
Hippocrates
THE PREGNANT GUT
What to eat for a healthier microbiome
YOU ARE WHAT YOUR MICROBES EAT
When I first started talking about pregnancy, birth and the microbiome back in 2014, I'd usually have to explain what gut bacteria was. In the last decade that has changed beyond recognition — gut health has come to the forefront of the health world, and quite rightly too.
There is no doubt now that the health of every human is inextricably linked to the health of their microbiome — those trillions of tiny microbes that live in and on us. We also know that the microbes we acquire at the very start of life are key to the foundation of an infant's lifelong microbial make-up, so making sure babies get the best possible 'starter kit' matters enormously. And the good news is that supporting a healthier gut microbiome benefits mother too — so everything you do for your baby, you do for yourself as well.
For a healthier gut microbiome, it starts with food. In the last 50 years the diet of people in the western world has changed radically — from a largely seasonal, locally produced diet of home-cooked food, to one dominated by mass-produced, highly processed foodstuffs transported across the world.
Fifty years may feel like a long time, but in terms of human evolution it is the blink of an eye. Our gut bacteria evolved alongside us over millennia, functioning like a rainforest ecosystem within our bodies — diverse, interconnected, and fundamental to our overall health. This rapid dietary shift has been deeply disruptive. Scientists have identified a 30% decrease in the diversity of gut bacteria over recent decades, and this reduction coincides with a 40% increase in non-communicable diseases such as type 2 diabetes, obesity and certain cancers. Research has increasingly confirmed that the gut microbiome plays a crucial role in nutrient acquisition, immune remodelling and protection against infection — so when diversity falls, the consequences are wide-ranging and significant. These two trends are very unlikely to be unrelated.
So what can we do to support our gut health in pregnancy?
WHAT ABOUT PROBIOTIC SUPPLEMENTS?
There are lots of claims made about the benefits of probiotics but the best source of probiotics for gut health is always food. A major 2026 systematic review and meta-analysis in BMC Medicine — covering 47 studies and over 1,000 healthy participants — found that probiotics do not significantly modify gut microbiota diversity in healthy populations by standard diversity measures. This challenges the core marketing claim of most probiotic supplements.
That said, probiotics aren't without value — the evidence is just more specific than the marketing suggests. They are well supported for particular situations: irritable bowel syndrome, recovery after antibiotic use, and certain digestive conditions. If you have been prescribed antibiotics during pregnancy — for Group B Streptococcus, for example — there is good evidence that probiotics can help restore microbial balance, and this is worth discussing with your midwife or GP.
Strain also matters enormously. Most inexpensive supplements contain only one or two strains, but research suggests that multi-strain products of eight or more strains are significantly more effective. If you are considering a supplement, look for one with documented clinical evidence for the specific strains it contains, rather than simply the highest bacterial count.
For most pregnant women, the most effective and enjoyable approach is through food. The best-evidenced sources of beneficial live cultures are:
Live yogurt — look for "live and active cultures" on the label
Kefir — one of the richest food sources of beneficial bacteria
Fermented sauerkraut and kimchi
Miso and tempeh — particularly good plant-based options
Pair these with plenty of prebiotic foods — the fibre that feeds your beneficial bacteria — such as oats, garlic, onions, leeks, bananas and legumes. Probiotics and prebiotics work best together, and a varied, plant-rich diet remains the single most evidence-based thing you can do for your gut microbiome, in pregnancy and beyond.