What are probiotics?

Probiotics contain living microorganisms that may help to repopulate or balance the gut microbiome of the host (1). An accepted definition of probiotics is ‘live microorganisms that, when administered in adequate amounts, confer health benefit on the host’ (2) They can be found in foods, such as kimchi or yoghurt, or taken in the form of a supplement (1).

Although probiotics are most well-researched in their ability to help with gut issues, like irritable bowel syndrome, there are a whole range of additional potential health benefits that have received attention in the research world (1). One of these areas of interest is the benefits of probiotic supplementation during pregnancy (1).

Claims versus Evidence

Let’s take a closer look at some of the health claims for the use of probiotics during pregnancy, and assess the level of evidence available to support these claims.

• Avoiding preterm labour – The claim is that probiotics can help reduce the risk of preterm birth by killing pathogens, reducing inflammation, and balancing the pH of the vaginal microbiome to make the vaginal environment friendlier for beneficial bacteria (1). A 2018 systematic review and meta-analysis, regarded as the highest level of scientific evidence, found no increase or decrease in preterm birth and other negative maternal or infant outcomes for those who took probiotics during pregnancy (1). These researchers do, however, also make a point of saying that further study needs to be done to confirm these findings, so it might be a case of ‘watch this space’. (1). 

• Gestational Diabetes – The worldwide prevalence of gestational diabetes is increasing, and, if left untreated, may cause complications including increased risk of miscarriage, pre-eclampsia, and preterm birth (3). It has recently been shown that an imbalance in the gut microbiome is associated with metabolic disease, such as type 2 diabetes, and insulin resistance (3). One Finnish study found that probiotic supplementation from early pregnancy reduced the risk of gestational diabetes developing from 34% to 13% (4). A recent meta-analysis concluded that probiotic supplementation during pregnancy may be an effective method of improving glucose metabolism in pregnant women with gestational diabetes (5). If you are at high risk of developing gestational diabetes, probiotic supplementation may offer a preventative effect, but, as always, consult a health professional first (5).

• Allergic Disease – Allergic disease, including eczema and asthma, continues to cause an increasing number of parents added stress worldwide (5). Pre- and postnatal probiotic supplementation has been shown to help prevent eczema development in babies, and this is most likely due to the impact that probiotics have on the gut microbiome, and its relationship with the immune system (5). Supplementation with probiotics during the 2nd half of pregnancy appears to have a positive effect on immune response, potentially reducing the baby’s risk for allergic disease development (5). The World Allergy Organization published guidelines in 2015 recommending that pregnant and breastfeeding women should consider probiotic supplements if their baby is at high risk of developing allergies (6).

Safety of Peri- and Postnatal Probiotic Supplementation

Generally, the use of probiotic supplements is considered safe during pregnancy, breastfeeding, and even in the first months of an infant’s life (6). Although there are relatively few studies specifically on the safety of probiotic supplementation, the studies that do exist so far most often report no negative side effects and no increased infection development for those who supplement with a probiotic during pregnancy, or after giving birth (5).

Important Note

The success of probiotic supplements depends on a variety of characteristics in the individual, including genetics, presence or absence of disease, metabolism, lifestyle behaviours, and the intake of other supplements or drugs (4). It is also important to note that different probiotic strains may offer different benefits, so it is always best to seek help from a health professional for guidance on the best supplement for you.