Fermented Foods & Pregnancy: What Every Mama Needs to Know

April 24, 2025 • fermented food • Ferments at Home • Gut Health • Kimchi

GoodBugs: A Taste Adventure...Even Before Birth

At the farmers’ markets here in New Zealand, I get asked this almost every weekend:

“Is it safe to eat sauerkraut or kimchi during pregnancy?”

The short answer? Absolutely yes!

But there’s more to it than just safety. Fermented foods during pregnancy can be one of the most powerful things you include in your nutrition.

Is it safe to eat fermented foods during pregnancy?

Yes! properly fermented vegetables like sauerkraut and kimchi are among the safest foods you can eat while pregnant.

There’s a misconception even among health professionals that fermented foods are risky in pregnancy. But traditional vegetable ferments are naturally protective.

Here’s why:

Salt creates an environment where harmful bacteria can’t grow
Fermentation lowers the pH, making it hostile to pathogens
Lactic acid bacteria are protective by nature
Refrigeration preserves these beneficial microbes

I call it the superfecta of safety.

As part of our MPI-required Food Control Plan here in NZ, I’ve done extensive research and lab testing on our products. We’ve tested ferments up to 14 months post-fermentation with zero pathogens detected. That matters.

When you compare that to foods historically associated with listeriosis (like certain soft cheeses) the difference is significant. Listeriosis outbreaks have primarily been linked to soft dairy products with higher pH and protein content, not vegetable ferments.

Historically, there’s even a myth that people drank fermented beverages like beer because you can’t brew beer with contaminated water. The same protective principles apply to sauerkraut and kimchi.

Vegetable ferments are acidic, salty, and self-protecting.

Can eating fermented foods during pregnancy benefit my baby’s gut health?

Yes — and the science behind this is pretty amazing.

Your gut microbiome gets passed on to your baby.

Your baby inherits much of your gut bacteria, especially during pregnancy and birth. That means your internal ecosystem becomes your baby’s starting point.

When your gut is healthy and diverse, it can lower the likelihood of eczema, allergies, and autoimmune issues. Research shows that many of the bacteria found in babies come directly from their mum’s gut — and those strains can stick around.

And it’s not just Mum. Dad’s microbiome health has also been shown to influence baby’s microbiome and overall outcomes.

So it makes complete sense to support gut health before conception and all the way through pregnancy.

Guidelines:

Eating a variety of fermented foods
Including prebiotics, probiotics, and postbiotics
Avoiding excess sugar and alcohol
Supporting beneficial strains like Bifidobacteria
Getting some natural microbial exposure (yes, even soil-based bacteria)

Ideally, both parents would focus on gut health 3–6 months before conception. That gives your microbiome time to optimise.

I’ve seen this firsthand.

My own journey into fermentation started because of my digestive struggles... constipation, gas, insulin resistance, PCOS, tooth decay. Each of my four children had different food sensitivities; eggs, dairy, soy, yeast, shellfish, even chlorine; and eczema often followed.

Looking back, I wish I had understood the power of the microbiome before they were conceived.

By my fourth pregnancy, I had my “Super Baby” microbiome plan (though he arrived slightly earlier than planned!). Thankfully by then I knew how to nourish their growing bodies with nutrient-dense food, and today they’re nearly free of allergies (aside from seafood) and eczema.

A little advice;-) Enjoy the kimchi while you’re pregnant. Babies aren’t usually big fans of chilli coming through in breast milk!

Are homemade ferments safe when pregnant?

Yes — homemade ferments are safe during pregnancy when made properly.

There is no magical safety difference between your home jar and my commercial sauerkraut.

If it looks right, smells right, and tastes sour — it is right.

What matters:

Clean equipment
Adequate salt
Time
Keeping vegetables submerged (anaerobic environment)
A properly sour taste (indicating low pH)

The only thing I do that you might not is measure pH digitally — but, your taste buds work just fine.

Are there fermented foods to avoid during pregnancy?

Yes — some higher-pH dairy ferments and soft cheeses carry more risk.

Soft cheeses have been linked to listeriosis outbreaks due to storage and pH factors (Listeriosis Outbreaks Associated with Soft Cheeses, United States, 1998–2014).

Vegetable ferments like sauerkraut and kimchi are far lower risk because they’re acidic and salt-stabilised.

The only thing you might occasionally see in a vegetable ferment is kham yeast — white and powdery like the outside of brie. It’s harmless, just cosmetic, and most people discard it.