Probiotics for Pregnancy

Dr Kate Stephens PhD Food and Microbial Sciences; Gut Microbiology (University of Reading), BSc Medical Microbiology

Many pregnant women take pregnancy supplements to support their baby’s development. But looking after their own health is just as important. After all, mum’s health has a direct impact on the health of her growing baby.

So, how can expectant mothers look after their health and well-being during their pregnancy? One easy option could be to supplement with friendly bacteria; known as probiotics.

This blog forms part 3 in the ‘Microbiome series’, the blog focuses predominantly on the microbiome in pregnancy and pregnancy safe probiotic strains. For more information on the microbiome see part 1 - The Microbiome - All You Need To Know or for a child’s microbiome Your Child's Microbiome.

Are probiotics safe in pregnancy?

Let’s start with the most important question; are probiotics safe to take during pregnancy?

Generally, probiotics and prebiotics are considered safe during pregnancy. This has been shown in large scientific studies1,2. A number of organisations including Babycentre UK and the American Pregnancy Association have also suggested probiotic supplementation during pregnancy to be safe and beneficial.

However, there is still one probiotic in particular: Saccharomyces boulardii, that is lacking in clinical research in pregnant women. This unique probiotic strain has shown many positive health benefits, including: reducing diarrhoea, having anti-inflammatory effects and inhibiting the growth of harmful bugs. However, due to a lack of testing in this one vulnerable subset of the population, pregnant women should exercise caution. Some researchers have therefore suggested not to use it at all, or at least to check with a doctor before using it.

Pregnant woman

Expectant mums who are considered ‘more at risk’, or those with a health condition (especially one related to the immune system) should always check with their GP before taking any pregnancy supplement, including probiotics.

If you are generally well and healthy and would like to take a probiotic, always check with the manufacturer’s guidelines, and ensure the probiotic strains are suitable in pregnancy. If in doubt, give the brand a call.

Now that we know that probiotics are largely considered safe in pregnancy, let’s take a look at how they work and some of the benefits these friendly bacteria may bring.

How do probiotics work during pregnancy?

Overall, probiotics help to rebalance the microbiome by topping up with levels of friendly bacteria. Once in the gut they can do many different jobs and support many aspects of health. Probiotics can be used by most people of all age groups.

Maternal factors microbiome.  Probiotics Learning Lab

Pregnancy forms part of the first 1000 days of life, more detail on this can be found Baby probiotics- all you need to know. A mother’s microbiome is believed to play an important role in both mums and baby’s health. When a baby passes through the birthing canal they are exposed to thousands of microbes. It’s therefore important for mum to have lots of good bacteria to transfer to the new-born. Even breast milk contains friendly microbes that can seed an infant’s gut.

So, to understand how probiotics may be beneficial during pregnancy, we need to understand what happens to the microbiome throughout the trimesters.

During pregnancy there are many microbial, immunological, hormonal and metabolic changes- these all influence one another. We actually see some big changes to the microbiome. There are still some mixed reports regarding how the gut microbiome composition changes, but the following is generally accepted amongst scientists:

beneficial microbiome in pregnancy  | Probiotics Learning Lab

1. Oral microbiome - an upcoming area of research is the changes to the oral microbiome. Pregnant women are at higher risks of oral health issues. This could be because the number of bacteria in the oral cavity increase; including bacteria associated with gingivitis and periodontal disease8.

2. Placental microbiome - There is some promising evidence to suggest placental microbes are present, however a lot of scientists do dispute this. In some cases, parts of microbes or DNA fragments have been found leading scientists to ask, if microbes are present what role do they have?

3. Gut microbiome - overall research suggests as pregnancy progresses towards the third trimester, we see significant microbial changes. In fact, one study showed when a poo sample from a pregnant woman in her third trimester was given to a germ free (sterile) mouse, the mouse gained weight and the microbiome looked like a microbiome from an individual with metabolic syndrome or diabetes3. These changes are regarded a normal part of pregnancy; however, in some women, this could explain why gestational diabetes and occurs. The same study also found a reduction in diversity and friendly bacteria, plus higher levels of inflammation. It’s not surprising that these microbial changes plus hormone increases cause a lot of GI upset in pregnant women!

4. Vaginal microbiome - As pregnancy progresses, the vaginal microbiome becomes less diverse and more dominant in friendly bacteria known as lactobacilli4. Lactobacilli have many protective effects; they help to create an environment for friendly microbes to thrive and inhibit the growth of many harmful ones. This is particularly important as vaginal infections such as bacterial vaginosis (BV) or thrush may increase the risk of recurrent miscarriages and pre term births5,6,7. You can read more about vaginal health in Vaginal flora- what all women should know.

On top of all these natural changes, the microbiome can also be further affected by stress levels, diet and antibiotic use.  These may impact mum’s health and baby’s health during gestation and post birth. Ultimately, they can reduce the level of friendly bacteria causing microbial imbalances (dysbiosis). So, probiotics have a lot of potential to tip the microbiome balance back to a more positive state and support overall health.

For example, antibiotic use during pregnancy has been associated with higher numbers of harmful bugs (such as Escherichia coli and Staphylococcus spp.) in the vaginal tract9. High levels of these bugs in new-borns have been associated with colic, eczema and allergies10,11. Therefore, probiotics specifically targeting vaginal health may be of benefit.

Are there benefits of taking probiotics during pregnancy?

With all the body changes during pregnancy, pregnant women can support many aspects of their health naturally with probiotics. They may find their digestion is just not the same, or they may want to boost their immune system, or avoid developing health conditions they had suffered in a previous pregnancy.

Let’s take a look at some of the common pregnancy worries and what may help! (Healthcare professionals can find more detailed information about each strain on the Probiotics Database)

Intimate health in pregnancy:

Why? Vaginal infections can result in unwanted pregnancy complications. Therefore, pregnant women need to take care of their vaginal health even before conception. Common over the counter medications can be useful to gain relief from an infection. However, they often only treat the symptoms rather than get to the root cause. Probiotics that are known to reach the vaginal tract, can promote a healthy vaginal microbiome, which in turn may lower the risk of vaginal infections.

Strain focus:

Combination of Lactobacillus rhamnosus GR-1® and Lactobacillus reuteri RC-14®: These two strains are the most researched strains for vaginal health. They’ve been researched in pregnant women and shown to reach the vaginal tract, even when taken orally. They have been shown to reduce the number of urinary tract infections and improve symptoms associated with bacterial vaginosis and thrush14,15,16.

Combination of Lactobacillus rhamnosus HN001 and Lactobacillus acidophilus La-14®: These two strains have been researched in women with bacterial vaginosis and thrush. Together, they have improved symptoms and reduced the risk of recurrent infections17,18,19.

Postnatal depression: 

Why? According to the NHS, it is thought at least 1 in 10 women suffer with postnatal depression20.  The exact cause is unknown and is likely due to many different reasons. One of which could be the changes we see in the gut microbiome and the inflammation this causes. There is a strong connection between the gut and brain (known as the gut-brain axis), so any changes to the gut environment can affect our mood. The gut is responsible for making many hormones including our ‘happy’ hormone serotonin.

Strain focus:

Lactobacillus rhamnosus HN001: One of the very few probiotic strains to be trialled specifically for postnatal depression. A gold standard trial including 380 pregnant women found L. rhamnosus HN001 was able to significantly lower depression and anxiety. The probiotic was taken during pregnancy and for six months post birth21.

Healthcare professionals can read more about Pregnancy and Mental health here.

Pregnant woman smiling reading book

General immunity in pregnancy:

Why? Pregnant women are more susceptible to coughs and colds, and this can be more of a worry in the first trimester. However, there’s actually not many choices available to pregnant women to boost their immunity. As 70% of the immune system lies in the gut, maintaining good gut health is vital. Some probiotic strains have been shown to reduce the risk of infections, boost immune cells, and reduce severity of, or recovery time from an infection.

Strain focus:

Lactobacillus paracasei CASEI 431®: This strain has been trialled in thousands of individuals and has been shown to boost the immune system and reduce recovery time by an average of three days22.

Gestational diabetes (GD):

Why? By the third trimester, the microbiome may resemble someone with diabetes or metabolic syndrome. These changes are considered natural and part of pregnancy. The problem may arise if a woman has existing problems with insulin management- increasing her risk of GD. For example, women over the age of 35, women with a high BMI, and women who had GD in previous pregnancies may all be at higher risk. GD can be tricky to manage and can cause further health implications for both mum and baby.

Strain focus:

Lactobacillus rhamnosus HN001: This is one of only a few strains of probiotic to have research on GD. Pregnant women who took this probiotic during pregnancy had a general reduced risk of GD. The findings were significant for women at higher risks e.g. those over 35 and women who developed GD in previous pregnancies. In fact, no women developed GD even if they had had it previously23.

IBS and bloating in pregnancy:

Why? One uncomfortable side effect of the increase in progesterone during pregnancy, is that it can cause excess bloating. Progesterone causes the smooth muscles of the intestinal wall to relax, meaning that food does not pass through as quickly. Slower digestive transit time allows for greater fermentation in the gut, which increases gas production, and thus bloating. Many pregnant women find their IBS is exacerbated during pregnancy this is likely due to the hormonal and microbial changes at play. As they are supporting another life, it’s really important that pregnant women look after their gut health to ensure they are digesting and absorbing their nutrients well. Probiotics provide digestive enzymes to help break down foods plus protect our gut cells to support good absorption rates. Poor gut health can result in poorly digested food and might mean that additional pregnancy supplements are not efficiently absorbed. 

Strain focus:

Lactobacillus acidophilus NCFM®: This is one of the most researched probiotic strains for digestive health. It’s been shown to bind to gut cells, support a healthy gut environment and significantly improve abdominal pain and bloating24.

Lactobacillus casei Shirota®: A well-researched strain supporting gut function. The strain has been shown to improve IBS symptoms and increase the numbers of friendly bacteria in the gut25.

Bifidobacterium infantis 35624: this strain has shown good results for IBS. In a gold standard trial, it’s been shown to improve overall IBS functions, particularly abdominal pain and bloating26.

Constipation in pregnancy:

Why? High levels of pregnancy hormones such as progesterone can cause constipation during pregnancy. In addition, reduced levels of friendly bacteria can affect the overall gut environment which can slow down gut movements.  Often pregnant women do not want to take pharmaceutical laxatives and their long-term use can lead to lazy gut. However, probiotics are gentle and non-habit forming, and offer a natural option.

Strain focus:

Bifidobacterium lactis HN019: Highly researched to improve constipation, gut transit times and promote healthy gut function12. The strain has been trialled in hundreds of pregnant women and also supports a range of other GI issues including flatulence and abdominal pain.

Bifidobacterium lactis BB-12®: Researched in thousands of individuals and has been shown to ease constipation and increase number of bowel movements each week13.

* Prebiotics can also ease constipation. When prebiotics are used in the gut by friendly bacteria, the bacteria produce short chain fatty acids which can stimulate natural bowel movements and promote a healthy gut environment.

Morning sickness in pregnancy:

Why? The increase in pregnancy hormones can cause nausea and sickness. It is particularly common during the first trimester. There is no research specifically looking into probiotics and morning sickness. B. lactis HN019 has been shown to reduce nausea in non-pregnant women, so this may be of benefit12. Often pregnant women with nausea or sickness tend to have low energy levels and the sickness may impact their gut microbiome. Taking a probiotic helps to top up the levels of friendly bacteria and boost energy levels.

When should I start taking probiotics in pregnancy?

Probiotics may have more benefit the earlier they are taken in pregnancy. The study for gestational diabetes for example was given to women at about 14-16 weeks. Studies looking into allergies and eczema in babies and children found that supplementation in pregnancy from 14 weeks again was beneficial. Other studies have showed that supplementation in the last month also gave protective effects against eczema, allergies and supported immune development in the newborn27,28. Probiotics for vaginal health should be taken sooner rather than later

So really it is never too late, or too early!

Hopefully all this information has highlighted how probiotics in pregnancy can be a natural and effective way to support a pregnant woman’s health. Pregnancy forms part of the first 1000 days of life so really can affect a baby’s health in the womb and after birth.  A happy and healthy mum increases the chance of a happy and healthy baby!

Remember if in doubt about the research, safety or when to start, always give the brand a call or email and discuss options that will suit your needs.



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