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pregnancy myths
5 Minutes

Boosting the immune system: why pregnant women/babies are more susceptible to bugs and allergies

The immune system is a wonderful thing. We also know it changes depending on what stage in life we are in. Pregnancy and our earliest days of life are two examples. We look at how, where there are areas of greater vulnerability and the science behind how you can support these two crucial stages. 

A pregnant woman’s immune system isn’t ’suppressed’ it is however different

Our immune system is designed to recognise ‘foreign’ cells and destroy them. Therefore it is a bit of a miracle that when an egg is fertilised and starts to grow it is not rejected by the body. After all, these are cells which are only half of our own DNA.  

Our immune system is phenomenally clever: 

In order to accommodate a growing baby our immune system DOES however change. During normal adult life there is a balance between Th1 and Th2 immune function. This helps us tolerate environmental exposures that enter our bodies (Th2) and also helps us ward off bacterial and viral infections (Th1). During pregnancy our immune system shifts: down regulating Th2 functions. This is why pregnant women can be more vulnerable to bacterial and viral infections. It is also why a pregnant woman can have adverse effects from influenza infections – which is why immunisation during pregnancy is so crucial. Click here for more.   

When our immune system does not shift as it should, we can get issues like recurrent miscarriage: 

Pioneering thinking by people like Dr Hassan Shehata argue that recurrent miscarriage is in some instances caused by our immune systems not shifting ‘as they should’. This can lead to the body rejecting what it perceives as ‘foreign cells’. Which gives some indication as to how important this delicate balance is for maintaining pregnancy. Click here for more on this theory of recurrent miscarriage. 

During pregnancy it is a mother’s immune system that supports a baby: 

We know that certain antibodies pass through the placenta to a developing baby. In fact, research from Harvard and MIT in the largest study to date shows that COVID antibodies are in fact passed and may offer protection to a developing baby. Good news. 

We also know that 70% of the mother’s immune system resides in the bacteria, fungi and virus within the gut. Known as the microbiome.  This provides the basis for a baby’s immune system which starts to develop during pregnancy. Click here for more. It is then passed through the birth canal, skin and breastmilk. 

In fact, certain cells (dendritic) from the mother’s gut will travel up towards the breast tissue in preparation for birth/within breastmilk. Clever stuff. 

A new baby’s immune system will mirror his/her mother’s: 

A mother’s microbiome provides the starting point. However, we know that in the early days a new baby is vulnerable to infection. Partly a result of immature immune system, but also the fact that it mirror’s a mother’s more Th2 dominant immune system during pregnancy. Once again, less Th1 (which includes defence cells like lymphocytes) = more risk of bacterial and viral infections. This is why it is so important to practise good hygiene with a new baby and why things like sterilisers are recommended for the first six months. 

Helping a baby’s immune system shift into balance: key for allergies! 

We know it takes at least a couple of months for a baby’s immune system to start to shift towards a more ‘normal’ adult balance between Th1 and Th2. In fact, it will take a good few years for this shift to complete. We also know that a more dominant Th2 system is more likely to react to allergens. Which is one of the reasons why babies may display an allergy/intolerance that they may later ‘grow out of’. 

So how can we help this shift happen? Evidence suggests DHA/EPA may help this immune system shift:  

We know that Omega 3 (DHA/EPA) have impressive ability moderating our immune systems. Specifically when it comes to things like chronic inflammation (where our body’s immune system is reacting in an abnormal way). Click here for more. 

However, new research  indicates that it may also help a baby shift towards a more balance immune system. This can help defend against bacteria/viruses better but also reduce the risk of the immune system firing up at something which is not an ‘enemy’ in the case of an allergic reaction. 

How to get more DHA/EPA? 

During pregnancy eating 2x portions of fatty fish a week has been shown to play a role in development of the immune system and even supporting neurological development. 

For those who don’t eat fish – a supplement (speak with your doctor first) is recommended. Click here. 

This also applies to breastfeeding women. We also know that breastmilk is key to protecting and helping a baby’s immune system develop. Full of antibodies and other prebiotic factors which help develop a baby’s own microflora which is home to the immune system. Click here for more. 

Research shows that formula fortified with DHA can also help: 

We know that breastfeeding isn’t always possible. The good news however is that this research also shows that supplemented formula can have as good an effect when it comes to this rebalance as breastmilk. Good news and something to discuss with your paediatrician. 

Other factors for supporting immune health: 

Old thinking was that Vitamin D was more for bone/teeth health. Which it is. However, we are also appreciating it’s role in immune function and development. The reality is many of us are deficient. Most guidelines now recommend at least 400iu/day in pregnancy and a supplement for a breastfeeding baby. Research has shown that getting enough can even help reduce the risk of infections and asthma. Click here for much more. 


This article is for informational purposes only. This article is not, nor is it intended to be, a substitute for professional medical advice, diagnosis, or treatment and should never be relied upon for specific medical advice. The information on this website has been developed following years of personal research and from referenced and sourced medical research. Before making any changes we strongly recommend you consult a healthcare professional before you begin.





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