When to start probiotics in pregnancy

Probiotics are sometimes called good or friendly bacteria. This is because they can balance out the bad bacteria in your gut, and help to keep your digestive system healthy (BDA 2019, NHS 2018a, Tinsley 2020). They can also stimulate your immune system to help it fight infection (BDA 2019, Tinsley 2020).

For example, some studies suggest that certain strains of probiotics can affect the good bacteria in your vagina and also be used to treat pregnant women who have a vaginal infection called bacterial vaginosis (BV) (Gomez Arango et al 2014, Cirino 2019, Dhanasekar et al 2019, Vandevusse 2013).

Other research has found that probiotic supplements may improve how blood sugar is controlled in women with gestational diabetes (GD) (Gomez Arango et al 2014, Zheng et al 2018). And some studies suggest that taking probiotics in pregnancy may reduce the likelihood of babies developing eczema (Gomez Arango et al 2014, Doege et al 2012, Pelucchi et al 2012, Yin et al 2019), and more are underway (Barthow et al 2016).

However, the evidence in each of these is inconclusive. If you’d like to take probiotics or prebiotics during your pregnancy, it's always best to talk to your GP or midwife before taking any supplements, and always ensure you follow the manufacturer's guidelines.

ASA. 2019. Food: Probiotic claims. www.asa.org.uk [Accessed March 2021]

Barthow C, Wickens K, Stanley T, et al. 2016. The Probiotics in Pregnancy Study (PiP Study): rationale and design of a double-blind randomised controlled trial to improve maternal health during pregnancy and prevent infant eczema and allergy. BMC Pregnancy and Childbirth 16: 133 [Accessed March 2021]

BDA. 2019. Probiotics: Food fact sheet. www.bda.uk.com [Accessed March 2021]

Chen Y, Li Z, Deng Tye K, et al. 2019. Probiotic Supplementation During Human Pregnancy Affects the Gut Microbiota and Immune Status. Front. Cell. Infect. Microbiol 9: 254 [Accessed March 2021]

Cirino E. 2019. Probiotics for Vaginal Health: Do They Work?. Healthline. www.healthline.com [Accessed March 2021]

Dhanasekar K, Shipla B, Gomathy N et al. 2019. Prenatal Probiotics: The Way Forward in Prevention of Preterm Birth. Journal of Clinical Gynecology and Obstetrics. www.jcgo.orgh [Accessed March 2021]

Doege K, Grajecki D, Zyruax B-C, et al. 2012. Impact of maternal supplementation with probiotics during pregnancy on atopic eczema in childhood – a meta-analysis. British Journal of Nutrition. 107: 1-6. Online first: July 2011. journals.cambridge.org. [Accessed March 2021]

Fiocchi A, Pawankar R, Cuello-Garcia C et al. 2015. World Allergy Organization-McMaster University Guidelines for Allergic Disease Prevention. World Allergy Organ J. Jan 27;8(1):4 [Accessed March 2021]

Gomathy K. 2013. Probiotics in Human Diet. In: Ramanathan A. ed. Probiotics in Sustainable Food Production: Current Status and Future Prospects. Volume 2: "Probiotics in Food Production". Bonfring: India, 209-211. www.conference.bonfring.org [Accessed March 2021]

Gomez Arango LF, Barrett HL, Callaway LK et al. 2015. Probiotics and pregnancy. Curr Diab Rep. 15: 567. [Accessed March 2021]

Jarde A, Lewis-Mikhael AM, Moayyedi P, et al. 2018. Pregnancy outcomes in women taking probiotics or prebiotics: a systematic review and meta-analysis BMC Pregnancy and Childbirth. 18:14. [Accessed March 2021]

Mueller NT, Bakacs E, Combellick J et al. 2014. The infant microbiome development: mom matters. Trends Mol Med. 2015;21(2):109-117 [Accessed March 2021]

Mundula T, Ricci F, Barnetta B, et al. 2019. Effect of Probiotics on Oral Candidiasis: A Systematic Review and Meta-Analysis. Nutrients. (10):2449 [Accessed March 2021]

NHS. 2018a. Probiotics. NHS, Health A-Z. www.nhs.uk [Accessed March 2021]

NHS. 2018b. Bacterial vaginosis. NHS, Health A-Z. www.nhs.uk [Accessed March 2021]

Pelucchi C, Chatenoud L, Federica T, et al. 2012: Probiotics Supplementation During Pregnancy or Infancy for the Prevention of Atopic Dermatitis. Epidemiology. 23:402-414 [Accessed March 2021]

Sanders ME, Guarner F, Guerrant R et al. 2013. An update on the use and investigation of probiotics in health and disease. Gut. 62(5): 787–796. www.ncbi.nlm.nih.gov [Accessed March 2021]

Semeco A. 2016. The 19 Best Prebiotic Foods You Should Eat. Healthline. www.healthline.com [Accessed March 2021]

Tinsley G. 2020. Probiotics 101: A Simple Beginner’s Guide. Healthline. www.healthline.com [Accessed March 2021]

VandeVusse L, Hanson L, Safdar N. 2013. Perinatal outcomes of prenatal probiotic and prebiotic administration: an integrative review. J Perinat Neonatal Nurs. 4:288-301 [Accessed March 2021]

Xie HY, Feng D, Wei DM, et al. 2017. Probiotics for vulvovaginal candidiasis in non-pregnant women. Cochrane Database Syst Rev.. (11):CD010496. www.cochranelibrary.com [Accessed March 2021]

Yin DG, Zhen H, Dian XY, et al. 2019. Effect of probiotic supplementation during pregnancy and infancy in preventing atopic dermatitis in children: a Meta analysis. Zhongguo Dang Dai Er Ke Za Zhi. 1:82-88 [Accessed March 2021]

Zheng J, Feng Q, Zheng S, et al. 2018. The effects of probiotics supplementation on metabolic health in pregnant women: An evidence based meta-analysis. PLoS ONE. 3(5): e0197771 [Accessed March 2021]

Key takeaways:

• Taking a probiotic supplement during pregnancy is probably safe. 

• Researchers have looked at whether probiotics improve pregnancy-related outcomes. Studies show mixed results.

• Talk to your healthcare provider before starting a probiotic supplement while pregnant.

The words bacteria and fungus may bring negative images to mind. It might make you think of infections and sickness. But, we have trillions of organisms that naturally exist in our bodies. This includes bacteria and fungi in our gut that are vital to our health. During pregnancy, the organisms in an expectant mother’s gut can change. This can have an impact on their unborn baby.

Probiotics are living microorganisms that affect the balance of bacteria in our gut. They’re available in certain foods, drinks, and supplements, and are linked to various health benefits. In the U.S. and Canada, about 4% of pregnant women take probiotic supplements.

Probiotic use during pregnancy has been studied for a wide range of reasons. This includes preventing preterm birth and vaginal infections. In this article, we’ll cover everything you need to know about probiotic use during pregnancy. Are they safe, do they work, and which one should you take?

What are probiotics?

Probiotics are a type of bacteria or yeast that may have health benefits when you ingest them. They're naturally part of foods and drinks like yogurt, kombucha, and sourdough bread. And they can be found in supplements and beauty products. 

How do probiotics work?

When you ingest probiotics, their final destination is your gut (intestines). Your gut is full of different types of organisms — including bacteria and fungi. These organisms make up your microbiome. Probiotics join your microbiome and change the balance of organisms that live there.

A healthy microbiome is important to your overall health. It supports your immune system and helps digest your food. In general, your gut is healthiest when you have a wide range of organisms living there. Studies show that the gut microbiome of people with certain medical conditions — including Type 1 diabetes and Type 2 diabetes — isn’t very diverse. This means they don’t have a wide variety of bacteria and fungus living in the gut.

To put it simply, the organisms in your gut microbiome may contribute to your overall health. This is why it may be wise to eat foods rich in probiotics or take a probiotic supplement.

Is it safe to take probiotics while I’m pregnant?

Probably. When you consume probiotics, they’re rarely absorbed into the blood. This makes it unlikely that probiotics will cause any serious side effects or harm to your developing baby.

Studies show that probiotic use during pregnancy doesn’t cause significant side effects. And, there hasn’t been an association with miscarriages or birth defects either.

But it’s difficult to say that any supplement is completely safe during pregnancy. Research on probiotics in pregnancy is limited. And, it’s not clear how effective they are (more on that below). Always talk to your healthcare provider before starting any supplement during pregnancy.

How effective are probiotics during pregnancy?

The gut microbiome changes during pregnancy. It might be partly due to changes in estrogen and progesterone levels in pregnant women. These sex hormones are known to affect the makeup of the gut microbiome.

Changes to the gut microbiome have been linked to nausea, constipation, and bloating during pregnancy. And, babies born by vaginal delivery versus cesarean section (C-section) have differences in their gut microbiome. This shows that a mother’s vaginal microbiome has an effect on her baby.

Below, we’ll talk about the research on probiotic use during pregnancy.

Treating pregnancy-related nausea and vomiting

Some research shows that probiotics help improve nausea symptoms in some people. And this might be true in pregnant women, too. A study of 32 pregnant women found that probiotics improved nausea and constipation symptoms.

Other than this small study, there’s minimal research on probiotic use and nausea and vomiting in pregnancy. More studies are needed to evaluate whether probiotics can relieve nausea in pregnancy.

Preventing preterm labor

Besides the gut, the vaginal microbiome is important for a healthy pregnancy as well. Abnormal changes in the vaginal microbiome can contribute to vaginal infections during pregnancy. Vaginal infections are linked to a greater chance of early delivery (preterm labor).

Studies on whether probiotics lower the risk of preterm labor have mixed results. One analysis of over 4,000 pregnant women found that probiotics didn’t raise the risk of preterm labor. But, the study didn’t find that probiotics lowered the risk either. This analysis included randomized controlled trials, which are the best types of studies.

Another study of close to 19,000 women did link probiotic foods to a lower risk of preterm labor. And another analysis of over 34,000 pregnant women found that drinking probiotic milk in early pregnancy lowered the risk of preterm labor. These studies were observational studies. These aren’t considered as reliable as a randomized controlled trial.

Preventing and treating common vaginal infections 

Group B streptococcus (GBS) is a bacteria that can live permanently (colonize) in the digestive tract and vagina. GBS colonization doesn’t usually cause symptoms. Most people don’t even know they carry it. But, it can cause infections in your baby if you have it at the time of delivery.

All expecting mothers are tested for GBS in the final weeks of pregnancy. If a mother is positive for GBS, antibiotics are usually given during delivery. This prevents the baby from getting infected.

Studies have looked at whether probiotic administration during pregnancy prevents vaginal GBS. One study found that probiotics may prevent or treat GBS colonization before birth. But other studies found that probiotics don’t prevent or get rid of vaginal GBS colonization.

Prevention of eczema in babies

Eczema is a chronic skin condition that can cause itchiness and skin inflammation. It affects up to 25% of children. And, up to 60% of children with eczema get it in their first year of life. Genetics play a role in eczema — babies with parents who have certain allergic conditions are more likely to develop eczema.

People with eczema may have different gut bacteria than people without eczema. Researchers have studied whether maternal probiotic use during pregnancy can prevent childhood eczema. One randomized control trial looked at mothers who had an allergic health condition. These mothers took probiotics or placebo (a pill with nothing in it) in their third trimester. They also took a probiotic in the first two months after giving birth and while nursing. The study found that babies born to mothers who took a probiotic were less likely to develop eczema in the first 2 years after birth.

Another analysis of seven studies found similar results. This analysis followed children ages 2 to 7 after their mothers used probiotics in pregnancy. They found that probiotics containing lactobacillus bacteria lowered a child's risk of eczema.

With this type of data in mind, probiotics are recommended in pregnancy in some situations. This includes if a child has a high risk for an allergy. 

Preventing and treating gestational diabetes

Diabetes diagnosed for the first time in pregnancy is called gestational diabetes mellitus (GDM). It can lead to pregnancy complications, like preterm labor. It’s also linked to problems in older children, like being categorized as obese.

A study of over 250 pregnant women found that probiotics lowered the chance of developing GDM. And a 2018 analysis found that probiotics lowered blood sugar levels in pregnant women without GDM.

But, another 2020 analysis had different results. The researchers found that probiotics improved blood sugar levels only in women that were already diagnosed with GDM. More studies are needed to determine the true effect of maternal probiotic use on GDM.

Which probiotic is best while I’m pregnant?

The short answer is that we don’t know. The studies of probiotics in pregnancy have looked at a variety of products. Commonly studied strains of bacteria include lactobacillus, streptococcus, and bifidobacterium. But the effectiveness and safety of one probiotic product doesn’t mean that another product is just as safe or effective.

It’s possible that the best probiotic for you depends on what you’re trying to accomplish. If you’re trying to minimize nausea, you may choose a different probiotic than if you’re hoping to prevent GDM. If you’re interested in taking a probiotic while pregnant, talk to your healthcare provider about which one may be best for you.

Can I take probiotics while breastfeeding?

Yes. Probiotics have been studied in breastfeeding mothers and are considered safe.

Human breast milk naturally contains a variety of bacteria that are good for your infant’s gut. It’s part of the reason that breast milk is so good for babies. It’s also why many infant formulas contain probiotics. 

Taking probiotic supplements during pregnancy is most likely safe. But we don’t know how effective they are. Probiotics may help improve certain pregnancy outcomes, like lowering the chance of preterm labor or childhood eczema. We just don't know whether the benefit is large enough to recommend them universally. This is why we need large, well-designed studies of probiotic use during pregnancy. Talk to your healthcare provider before starting a probiotic supplement during pregnancy.

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