Gut Health

How Pregnancy Alters a Woman’s Gut Microbes

How Pregnancy Alters a Woman’s Gut Microbes

To create the perfect environment for her growing baby to thrive, a woman’s body undergoes all kinds of changes during pregnancy. Her blood volume increases, her breasts prepare to manufacture milk, and even her brain alters itself in ways that will help her better bond with her child.1

But these aren’t the only important transformations going on during pregnancy—the microbial composition in a woman’s digestive tract also undergoes a big shift during her third trimester.

Here’s how pregnancy alters the gut microbiome, and what it means for you and your baby.

What’s a Microbiome?

When you’re expecting, it’s an amazing feeling to know a beautiful little life is developing right inside you. But the truth is your baby isn’t the only other living organism on board, and you actually haven’t been alone in there for a very long time!

Within each of our bodies (whether pregnant or not) lives an active community of billions of bacteria, referred to collectively as the microbiome. A large percentage of this microbiome resides in the gut, where close to 80% of your immune system is also located.2

Bacteria tends to get a bad rap, but thankfully not all bacteria are harmful. Ideally about 85% of your microbiome should be comprised of beneficial bacteria called probiotics. These friendly little guys effectively crowd out the bacterial strains you don’t want, and work with your cells and immune system to maintain overall mind and body health.


Learn more about benefits of probiotis For Expecting and Nursing Moms.


How Do We Get a Microbiome?

When a baby is first born, she doesn’t have a mature, diverse microbiome like you do—in fact, her gut is almost sterile when she makes her grand entrance into this world. While in the womb though, she’s exposed to some microbes via the placenta, both from Mom’s gut and oral microbiome, which get her budding microbial community started.

During delivery, as baby makes her way down the birth canal, she gets her first significant infusion of microbial life from Mom’s vaginal bacteria. After she’s born, breast milk and skin to skin contact introduce her to more helpful probiotic strains. These early colonizers form a solid foundation for her miraculous microbiome, which if properly balanced and maintained will help keep her healthy for the rest of her life.

What Happens to the Microbiome During Pregnancy?

During pregnancy, particularly in the third trimester, a woman’s gut microbiome undergoes a dramatic change, actually coming to resemble that of people who are more likely to develop diabetes. This type of microbiome composition is associated with inflammatory markers, decreased bacterial diversity, and increased blood glucose and body fat in order to help moms-to-be provide proper nourishment and an optimum environment for their babies during the period of most intense growth before birth.3

Don’t worry though—although this sort of microbial profile is normally unhealthy, during pregnancy these changes don’t pose any sort of health threat to the mother! And these changes are going to happen regardless of Mom’s weight, diet, and even whether she takes probiotic supplements or antibiotic medications. Once the baby is born though, Mom’s microbiome automatically begins to revert back to its pre-pregnancy state.

Interestingly, the vaginal microbiome also shifts during this time, with the beneficial Lactobacillus species becoming dominant in preparation to jump start baby’s microbiome during delivery.4

How Can I Support My Microbial Health While I’m Pregnant?

Microbial changes during pregnancy are inevitable, and that’s a good thing because these changes give your little one a real advantage as her body grows and develops inside you. To give your microbiome the TLC it needs at this time, it’s helpful to supplement with a high-quality, time-released probiotic tailored for expectant and nursing mothers such as PRO-Moms, as well as an oral probiotic to help maintain excellent dental health.

Taking probiotics during pregnancy helps you keep feeling your best in a number of ways—research shows it may even help Mom to return to an ideal weight more easily after delivery.5 And during your gestation, maintaining a balanced gut encourages glowing health, strong immune function, healthy blood sugar levels already within the normal range, and fewer issues from month to month.6, 7 Probiotics also support the body’s ability to absorb nutrients from meals, which benefits both Mom and the little one she’s carrying.

Adopting gut-friendly habits goes a long way toward helping you feel great throughout your pregnancy, particularly since a modern lifestyle can be tough on the gut. Start by enjoying a healthy diet with lots of fresh produce and whole grains (preferably organic), as well as probiotic-rich cultured and fermented dishes. Certain foods including bananas, asparagus, and onions are considered important prebiotics because they contain fibers that provide just the right nutrition for friendly bacteria. And, incorporating an organic, food-based prebiotic powder supplement is the perfect way to fuel your mighty microbes! Avoid processed foods, refined sugar, artificial ingredients, pesticides, and GMOs, as these harm beneficial microbes.

Keeping active is good for your gut too, so look into safe, gentle exercises that are also fun, such as hiking, swimming or yoga. Since stress is bad for your friendly flora, it’s important to also take time for relaxing activities like meditation—or even a trip to the spa.

While it’s important to take prescription medicines when you need them to get and stay well, only take these medicines when you truly need them, as many of them have a detrimental effect on the microbiome. Avoid antimicrobial cleansers as well—they indiscriminately kill helpful organisms along with undesirable ones.

Give Your Baby a Microbial Advantage

Once your baby is ready to make her grand entrance, there are lots of ways you can encourage her microbiome to develop healthy diversity:

• If possible, deliver vaginally to expose your baby to your vaginal microbes.

• When you breastfeed, your baby will drink in lots of friendly probiotics along with the perfect nutrition for her growing body. When breastfeeding isn’t an option, you may want to explore milk banks that supply screened milk from healthy moms. If your baby is formula fed, consider supplementing with an infant probiotic powder that you can gently place on her tongue.

• Indulge your little one with lots of hugs, kisses, and skin-to-skin cuddles to share the benefit of your mature microbiome along with your love. During baby’s first weeks of life, avoid using cleansing products on her entirely, and instead wash her gently with pure water and a soft cloth. When she’s ready for baby wash and shampoo, avoid anything antimicrobial that could damage her delicate new microbiome.

• When it’s time for solid foods, feed her a healthy diet rich in whole, natural foods.

Pregnancy is a remarkable journey, as filled with wonder as it is full of change. But when you focus on microbial health for you and your baby, you’ll be able to sail smoothly through all the unexpected twists and turns ahead of you. And when you finally get to see the tiny face of your newest family member, you’ll know you’ve given her a precious gift—and that the best part of the journey is yet to come.

Did you find this article helpful? Then feel free to check the next one - When you’re pregnant, hungry, and in a hurry


1. Hoekzema, E., Barba-Müller, E., Pozzobon, C., Picado, M., Lucco, F., García-García, D., … Vilarroya, O. (2016). Pregnancy leads to long-lasting changes in human brain structure. Nature Neuroscience, 20(2), 287-296. doi:10.1038/nn.4458

2. Panda, S., Guarner, F., & Manichanh, C. (2014). Structure and functions of the gut microbiome. Endocrine, Metabolic & Immune Disorders Drug Targets, 4, 290–299.

3. Nuriel-Ohayon, M., Neuman, H., & Koren, O. (2016). Microbial Changes during Pregnancy, Birth, and Infancy. Frontiers in Microbiology, 7. doi:10.3389/fmicb.2016.01031

4. Prince, A. L., Chu, D. M., Seferovic, M. D., Antony, K. M., Ma, J., & Aagaard, K. M. (2015). The Perinatal Microbiome and Pregnancy: Moving Beyond the Vaginal Microbiome. Cold Spring Harbor Perspectives in Medicine, 5(6), a023051-a023051. doi:10.1101/cshperspect.a023051

5. Obesity, Study In Pregnant Women Suggests. ScienceDaily. Retrieved March 21, 2017

6. Lindsay, K. L., Walsh, C. A., Brennan, L., & McAuliffe, F. M. (2013). Probiotics in pregnancy and maternal outcomes: a systematic review. The Journal of Maternal-Fetal & Neonatal Medicine, 26(8), 772-778. doi:10.3109/14767058.2012.755166

7. Brantsaeter, A. L., Myhre, R., Haugen, M., Myking, S., Sengpiel, V., Magnus, P., … Meltzer, H. M. (2011). Intake of Probiotic Food and Risk of Preeclampsia in Primiparous Women: The Norwegian Mother and Child Cohort Study. American Journal of Epidemiology, 174(7), 807-815. doi:10.1093/aje/kwr168


Roberta Pescow is a writer at Hyperbiotics and proud mom of two amazing and unique young men. Natural wellness is a subject she’s passionate about, so she loves sharing information that helps others discover all the ways probiotics support glowing health and well-being. To learn more about how a healthy microbiome can enrich your life, subscribe to our newsletter.