Are Probiotics Safe During Pregnancy?

Probiotics are commonly known as good bacteria and are mostly used for beneficial effects on the digestive organs. Although they are considered safe to use, what do we know about their safety in pregnancy? Let’s explore what medical literature says on this topic.

What are the benefits of probiotic use?

According to the World Health Organization (WHO), probiotics are living microorganisms that are beneficial to the host when used in adequate amounts. Typically, our body hosts numerous strains of microorganisms, which are more common in the mouth, gut, vagina, and skin. These microbial communities are considered normal flora of the body, and depletion or overgrowth of species characteristic for specific organs can result in various health issues.

For example, the gut microbiome (community of microorganisms living in the intestines) is important for immunity, metabolism, and digestion. Probiotic microorganisms can regulate the flora of the gut.

Types of probiotics during pregnancy

The types of bacteria living in the gut can vary between people. Three types show dominance in adults: Bacteroidetes, Firmicutes, and Actinobacteria. However, in pregnant women, the gut microbiome changes; Proteobacteria and Actinobacteria increase, and beneficial species such as Roseburia intestinalis and Faecalibacterium prausnitzii may decrease.

Some bacteria, including Lactobacillus, Bifidobacterium, and yeast (Saccharomyces), are widely used strains in probiotics. In the general population and pregnant women, probiotics containing these strains are the main components of probiotic supplements.

Potential effects of probiotic use in pregnancy

Probiotics are used for preventive and treatment purposes. In addition to supplements, some dairy products enriched with probiotics are available for consumption. As in the general population, there are several benefits of probiotic use in pregnancy.

Improved digestive health

Hormonal changes during pregnancy slow gut motility and may have effects such as constipation, nausea, and vomiting. Additionally, pregnancy hormones can affect the gut microbiome and play a role in these digestive disturbances. A study that examined the effects of Lactobacillus in pregnant women has found that after 16 days of probiotic use, nausea, vomiting, and constipation can potentially become less severe.

Gestational diabetes

Gestational diabetes (GDM) is a condition of high blood glucose levels associated with pregnancy. If the mother’s blood sugar levels are not regulated to be within normal ranges, high blood glucose can have major effects on the mother and the baby.

Probiotic use is one of the possible lifestyle adjustments to keep blood sugar levels within normal limits, but studies on this topic are limited and of low quality. A most recent meta-analysis concluded that probiotics do not reduce the risk of developing gestational diabetes. On the other hand, another meta-analysis shows the beneficial effect of probiotics on GDM-associated outcomes and complications, such as fasting blood glucose levels, fasting insulin levels, newborn birth weight, and fewer neonatal intensive care admissions.


Preeclampsia is a high blood pressure disorder, typically diagnosed after 20 weeks of pregnancy. In some cases, it may also affect the kidneys and women may experience protein loss in urine. In severe cases, preeclampsia may have life-threatening consequences. Several studies assessed the potential protective effect of probiotics in preeclampsia development.

Initial studies suggested that probiotics may reduce preeclampsia risk. For example, a Norwegian study reported a reduced risk of preeclampsia by 20% with daily dairy product intake supplemented with probiotics. They also noted that daily (39%) and weekly (25%) dairy product consumption may have more prominent effects in reducing the risk of severe preeclampsia.

Another study, again from the Norwegian population, showed that the timing of probiotic milk use also matters. When consumed during late pregnancy, probiotics led to a lower preeclampsia risk, while there was no protective effect when milk was used before pregnancy and in early pregnancy.

On the other hand, a Cochrane meta-analysis with over 950 participants suggests that women using probiotics compared to those who receive placebo pills have an 85% increased risk of developing preeclampsia. However, a recent meta-analysis with 2,400 pregnant women reported no association between probiotic use and preeclampsia risk.

Mood regulation

Mood disturbances are common during pregnancy and after birth. For example, approximately 17.2% of women suffer from postpartum (after birth) depression. Thus, researchers also focus on the mental health effects of probiotic supplementation.

Research shows that probiotic use in combination with myo-inositol and enriched micronutrients started during conception planning and continued during the pregnancy does not have a significant impact on mood changes and maternal anxiety.

Management of vaginal health

Vagina has its own microbiome, and depletion of flora bacteria can lead to excessive fungal (Candida spp.) growth. On average, in 30% of pregnancies, women experience vulvovaginal candidiasis.

Findings from a Malaysian study suggested that probiotic supplementation for eight continuous weeks may have potential restoring effects on the vaginal microbiome.

Other benefits

Women with a low-functioning thyroid gland (hypothyroidism) are prone to developing overgrowth of bacteria in the small intestine (small intestinal bacterial growth-SIBO). A study that explored the effects of probiotic supplementation in pregnant women with hypothyroidism in early pregnancy revealed potential beneficial effects on the thyroid and SIBO-associated symptoms.

Are there any benefits for babies?

Studies show that probiotic supplementation during pregnancy doesn't change the gut microbiome of newborn babies. However, exposure to probiotic supplementation before birth may have a role in the development of allergic conditions. For example, a recent meta-analysis showed that babies born to mothers who used probiotic supplementation during pregnancy may have a 21% reduced risk of food allergies. Additionally, these babies may carry 49% and 43% reduced risks of cow milk and egg allergies, respectively.

Eczema or atopic dermatitis is an inflammatory allergic condition of the skin. Infants with eczema have dry skin and itching symptoms and are prone to developing skin infections. In a Finnish study, mothers with allergic diseases were supplemented with probiotics for the last two months of pregnancy and the first two months of breastfeeding. Study results showed that probiotic use reduced eczema development in their infants by 83–84%. However, a most recent study with 13 years of follow-up suggests that probiotic use during the last month of pregnancy and infant supplementation for six months protects only Cesarean-delivered children from developing allergic diseases.

Are probiotics safe during pregnancy?

Researchers from Canada analyzed 100 studies that explored the effects of probiotic consumption during pregnancy. Out of these, adverse effects associated with probiotic supplementation were reported in 11 studies. Most of these complaints were related to digestive system disturbances. The authors concluded that probiotic supplementation does not increase the overall risk of adverse effects related to treatment. Given the current literature information, probiotic use during pregnancy is considered safe with minimal reported side effects.

Side effects for mothers

Probiotics, with their live microbiotic content, carry a risk of making you sick with these microorganisms. Although such adverse effects are rare, literature mentions one in 1 million risk of spreading the infection with Lactobacillus and one in 5.6 million risk with Saccharomyces boulardii use. Generally, healthy individuals do not develop such complications. However, people with impaired immune systems might be vulnerable to such supplements.

Although rarely, some studies report some side effects in women using probiotics during pregnancy. Some of them are listed below:

  • Nausea
  • Diarrhea
  • Constipation
  • Bloating
  • Stomach ache
  • Changes in stool consistency
  • Vaginal discharge

Can probiotics harm the baby?

The current medical literature reports very limited side effects on infants related to maternal probiotic use during pregnancy. Infantile diarrhea is one of the most investigated side effects. Analysis of 208 mother and infant pairs does not find a significant difference in the occurrence of diarrhea in newborns compared to those whose mothers did not receive probiotics.

A recent meta-analysis also reports that the current evidence is too limited and uncertain to show whether probiotic use might potentially lead to low birth weight, stillbirth, neonatal infection, or death.

How to use probiotics while pregnant

The reason for probiotic use could be prophylactic or therapeutic. Depending on the reason, the timing, duration, and types of probiotics can be decided. A study with over 2,000 participants showed that 13.7% of mothers report probiotic use during pregnancy. Interestingly, probiotic-using parents tended to use homeopathic products and had a smoking history. The authors also concluded that parents with 'less favorable behavior' might use probiotics without prescription as compensation efforts. Therefore, if you are wondering how to benefit from probiotics during pregnancy, it is always recommended to consult your physician before choosing the most appropriate method.

In conclusion, according to current evidence, probiotics are most likely to be safe in pregnancy. However, it is important to discuss the purpose, timing, duration, and type of supplementation with a healthcare provider since there may be probiotic products on the market that may not be suitable for you.


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