Pregnancy, antibiotics and baby’s immune system

Pregnancy, breastfeeding and antibiotics blog image-min

From the moment you fall pregnant, your body starts to change; what you might not know is that these changes can lead to an increased risk of picking up an infection, which can mean needing to take a course of antibiotics. Certain macrolide antibiotics have the potential to cause congenital abnormalities in newborns. The four most common are azithromycin, clarithromycin, erythromycin, and roxithromycin.

So do you take the antibiotics or not? What effects will antibiotics have on the baby, both short and long-term? What are the alternatives to taking antibiotics?

Let’s take a closer look

A balanced and diverse microbiome is essential to help program the immune system of a newborn so that it is able to respond to pathogens, but at the same time, does not overreact to environmental allergens and to foods introduced during weaning.

The beneficial bacteria in our gut form a physical barrier and prevent pathogens from entering the body. They also keep the immune system on alert so that it can respond quickly and effectively to invaders.

Numerous studies have shown that when children supplement with probiotics, they get fewer colds and respiratory tract infections, and recover more quickly when they get ill.  Conversely, antibiotic use during infancy has been linked to an increase in the risk of developing allergic diseases, asthma, IBS and Inflammatory Bowel Disease (IBD) later in life.

The intrauterine environment, although traditionally considered to be sterile and free of microbes, has been found to harbour a variety of microbes.

Up until recently, it was believed that a baby’s first exposure to bacteria occurred during birth. But some recent research has identified a potential ‘placental microbiome’ which the baby is already in contact with in the uterus.  However, the impact of this microbiome is still unclear, and the most significant exposure is still believed to be from the mother’s vaginal microbiome during natural birth, or to the hospital environment in the case of a C-section delivery.

This initial exposure determines the composition of the baby’s gut, and is crucial to enable beneficial bacterial to colonise it and help build the baby’s immunity.

What can affect a baby’s microbiome?

The mother’s microbiome

70-80% of the immune system is located in the gut, and therefore the mother’s gut microbiome plays an important role in the baby’s health and immune development.

When a baby is born, they move from a largely sterile environment, their mother’s womb, to the outer world, one full of microorganisms. Both animal and humans learn to adapt to this situation by being exposed to their mother’s microbes from the moment of birth, as delivery kick-starts the immune system of all newborns. 

Nature Medicine published a study that suggests that the mother’s gut microbiota may play an essential role in this transference as it fosters the production of the white blood cells in charge of fighting infections, granulocytes, during the first days of life.

Taking antibiotics during pregnancy

Many women are prescribed antibiotics throughout pregnancy, several of which are known to cross the placenta and transfer to the foetus. Antibiotics during pregnancy can alter the mother’s microbiome and therefore the microbial profile her baby acquires.

As we know, antibiotics kill off not only the bacteria causing the infection, but also the ‘friendly’ bacteria in the microbiome. The resulting imbalance within the microbiome is known as dysbiosis.

A baby’s early microbiome, acquired from the mother via vaginal delivery, helps to shape the infant’s developing immune system in the first weeks and months of life. As the baby is passing through the birth canal, it picks up lactobacilli strains of bacteria, through its nose, its mouth and the bacteria also coat the baby’s skin. 

If the mother has a dysbiotic vagina, then there is the risk that the baby’s gut will be colonised by pathogenic strains of bacteria instead of the beneficial strains.

When a mother takes antibiotics during pregnancy, her microbiome will be altered which will affect both the baby’s microbiome and early immune responses. This may increase the risk of childhood infections, as well as digestive disorders such as IBS.

In fact, a recent Danish study showed that a mother’s exposure to antibiotics during pregnancy was associated with an increased risk that her child would develop a severe infection (requiring hospital admission and probably antibiotics) in the first six years of life.

The increase in risk was greatest among children whose mothers were prescribed more antibiotics and those who were prescribed antibiotics in the final three months of their pregnancy.

Method of birth

Compared to babies born vaginally, babies born by C-section have reduced populations of Bifidobacterium, a type of bacteria associated with health benefits and a stronger immune system.

Most women who have a caesarean are now offered antibiotics before the delivery to help prevent them from developing postoperative infections, meaning that the baby also receives a dose of antibiotics via the placenta. This could also account for some of the differences in microbiomes depending on the birth method.

An imbalanced microbiome following birth by C-section can double the risk of developing egg and milk intolerances, a factor involved in the development of both eczema and asthma.

The largest-ever study of neonatal microbiomes published in Nature Today also revealed that the microbiome of vaginally delivered newborns did not come from the mother’s vaginal bacteria, but from the mother’s gut. More research is still needed, but it is an interesting insight.

How a newborn baby is fed

It’s a divisive and sensitive topic, but how a newborn is fed can impact the development of the gut microbiome during the first few months of life.

Breast milk provides beneficial bacteria which are transferred from the mother’s gut to the mammary glands. Breast milk also contains large amounts of oligosaccharides, a type of carbohydrate, that provide nourishment for beneficial bacteria in the gut and help to promote their activity.

As I’ve mentioned, use of antibiotics during a woman’s pregnancy can reduce the number and diversity of beneficial bacteria in the gut, and this can impact the quality of the breast milk later down the line.

Breast milk contains all of the different antibodies, but secretory immunoglobulin A (sigA) is the most abundant. This milk-derived sigA is a significant source of passively acquired immunity for the baby during the weeks before their own internal production of sigA occurs.

Breastfed babies (for at least 6 months) may therefore be at a reduced risk of many chronic diseases.

How can you boost your baby’s microbiome?

Before birth

If you are expecting a baby, it’s all the more important to look after your own microbiome, which you can do by supplementing with probiotics (choose ones that are suitable during pregnancy like the Just For Tummies Live Bacteria capsules. Take one before breakfast and one before bed, with a small glass of water), and increase your intake of fibre-rich prebiotic foods.

This will help to ensure your baby benefits from your beneficial bacteria during birth and when you are breastfeeding. If a C-section is planned or performed in an emergency, you can give your baby a probiotic supplement straight from birth to support their gut microbiome, and continue to take a probiotic yourself as well as eating fermented foods such as sauerkraut, kimchi, miso soup and kefir, and fibre so that bacteria is passed on through breast milk too.

Click on the image to buy my Live Bacteria Probiotic Capsules

During birth

You can supplement your baby with probiotics that are well researched and safe for an immature gut. One study found that babies who were supplemented with a blend of 4 strains of bacteria (including Lactobacillus paracasei and salivarius) for 6 months, were 57% less likely to develop allergic eczema than those receiving a placebo, and 44% less likely to develop allergic reactions to pollen, cow’s milk, eggs, and house dust mites.

In premature babies, supplementation with probiotics has also been shown to halve the risk of a severe and fatal condition called necrotizing enterocolitis, which is common in preterm infants.

During the first few months of the baby’s life

Once your baby starts weaning, slowly introduce a variety of fruits and vegetables rich in prebiotic fibres, such as avocado, banana, onions and leeks. Generally speaking, it is not recommended to start weaning until a baby is 6 months old, although there may be babies who show visible signs of wanting more than just milk at 4 or 5 months old. 

It is important to note that the baby’s gut is still permeable up until around 6 months (to allow the passage of the mother’s antibodies into their own bloodstream), and this could lead to food intolerances if certain foods are introduced too early. 

In cases where weaning is started before 6 months, it would be advisable to wait for the 6 month mark for the introduction of fermented foods. 

Giving babies bone broth (as well as milk) before weaning can help seal a leaky gut with the collagen, gelatin and other minerals found in the broth.  This can help ensure that the digestive system is ready for solid foods, as well as reduce the risk of developing food intolerances and allergies from early weaning.

Baby eating yoghurt

Once the baby is 6 months old, you can introduce fermented foods, in small amounts, which naturally contain beneficial bacteria, such as organic yoghurt or kefir.

Lastly, if your baby needs to take antibiotics, giving them a probiotic supplement both during and after treatment, as this can help to reduce disruption to their gut bacteria and the risk of side effects. Just make sure that they take the probiotic supplement at least 2 hours before or after the antibiotics to protect the beneficial bacteria.