What Happens to The Immune System During Pregnancy?

Your immune system has one basic function: to keep you healthy. By using a complex array of biological tools and weapons, your body can fend off most invaders, including viruses, bacteria, and the occasional fungus. 

But pregnancy introduces some additional complexity for all those t-cells and antibodies (not to mention the scientists and doctors that study them). Your immune response to something like a cold or flu may be different when you’re pregnant than you would normally expect. So knowing more about typical pregnancy immune system responses can help you better plan for your nine month term.

After all, keeping your immune system in tip top shape is a way to keep you and your baby healthy. 

An Evolving Understanding of Your Pregnancy Immune System

Scientists used to think that women’s immune systems became weaker as pregnancy progressed. To these researchers, it seemed logical to think about the fetus as a kind of transplanted organ. 

When an organ recipient gets a new liver or lung or heart, the patient must take immunosuppressive drugs for the rest of their life. This stops the immune system from seeing the transplanted organ as a threat and initiating an immune response (a process known as rejection). A fetus must require the same kind of protection, researchers thought, which meant that immunity during pregnancy must be diminished.

Relying on Your Immune Response

But new research suggests that this is not what happens when you become pregnant. At least, not exactly. 

Modern scientists and researchers have observed that the interaction between your pregnancy and your immune system is much more complicated than first suspected–in many ways, it’s a kind of complex dance. 

This dance between your body, your baby, and your immune system continues throughout your pregnancy. And there are certain aspects of your immune response that actually become stronger when you’re pregnant. For example, we now know that implantation of the embryo in the uterine wall cannot happen without a strong immune system reaction. That immune response causes inflammation in the uterine lining (the same type of inflammation that results from an injury) which is essential to successful implantation.

Will You Feel Sicker?

Further research has reinforced the notion of a particular strong immune system for pregnancy women, suggesting that the initial 15 weeks of pregnancy depend on a potent immune response. 

Some studies have even shown that the presence of various types of T-cells increase while you’re pregnant. These T-cells (or white blood cells) are responsible for a few different aspects of your immunology. Regulatory T-cells (or Tregs) and so-called killer T-cells are just two types–and during pregnancy your body promotes and amplifies production of each.

During the course of your pregnancy, your body’s immune system will work hard to protect both you and your baby. But that doesn’t always necessarily work in your favor symptomatically. Scientists have known for some time that ailments such as the common cold or influenza tends to hit pregnant women harder than non-pregnant women. 

The assumption always used to be that this was because pregnant women’s immune systems were weaker (again, working on that organ transplant-like situation). The reality, however, is that colds and flus tend to be more severe in women because their immune systems are more powerful–the more severe symptoms are due to an overly strong inflammatory response. 

Practical Tips to Keep You Healthy

So you can see why knowing more about how the immune system operates while you’re pregnant can be important information. Researchers are still looking into exactly what happens when–and to a certain extent, much of this information is interesting… but mom’s-to-be are want to know about practical steps they can take.

Whether you’re pregnant or not (but especially if you’re pregnant) it’s important to do all you can to keep your immune system functioning optimally. There are a couple of ways you can do this:

• Make sure you’re getting plenty of sleep: There’s nothing quite like a good night’s sleep–especially when it comes to keeping illness away. Lack of sleep can compromise your immune system. True, getting a solid eight hours of sleep isn’t always possible when you’re pregnant. But prioritizing rest, relaxation, and recovery can help keep your immune system in good shape.

• Eat a balanced and healthy diet: Your immune system requires an assortment of vitamins and minerals in order to function properly. The best way to get those vitamins and minerals (especially when you’re pregnant) is from your food! Generally, this means making sure to eat lots of fruits and vegetables. If you aren’t getting enough vitamins and minerals from your food, talk to your OBGYN about vitamin supplements.

• Take prenatal vitamins: Your OBGYN will likely prescribe a course of prenatal vitamins for you to take during your pregnancy. These vitamins are specifically calibrated to promote the health of pregnant women (and their babies). In the same way, these prenatal vitamins can help keep your immune system working properly.

• Hydrate, hydrate, hydrate: Though it may come as no surprise, it’s important to remember that hydration is fundamental to a healthy body. When you drink plenty of water, it’s easier for your immune response to detect and address infections, disease, and injury. Chronic dehydration can make everything just a little bit more challenging and lead to immune system breakdowns.

• Exercise: Exercise is famous for improving your mood–but it will also improve your immune response. Remember that the goal of the exercise here is just to get your body moving; not necessarily to become more fit and certainly not to lose weight (unless directed to do so by your physician). A few minutes of walking here and there can help keep your body in balance–immune system included.
• Immunizations: Consider receiving the immunizations recommended during pregnancy as advised by your OBGYN.  

It should be noted that your body’s immune system will take some time to return to normal after the birth of your baby. In other words, the roller coaster doesn’t end with delivery! Your OBGYN may monitor your hormone levels and blood work to make sure everything gets back to where it should be.

What About Non-Normal Immune Responses?

There are a couple of reasons you may want to talk to your OBGYN about your immune system while you’re pregnant. Everyone’s pregnancy immune system, after all, will very much depend on how your typical immune system behaves. So you should talk to your OBGYN if you:

• Have a history of a weakened or abnormal immune response.
• Have trouble keeping your immune responses in a healthy range during pregnancy.
• Your body does not absorb vitamins and minerals normally.
• Exhibit a known history or current diagnosis of an autoimmune disease. 
• Have difficulty staying hydrated or are unable to tolerate eating sufficiently 
• Are having trouble falling asleep or staying asleep at night

Each of these conditions can complicate your immune response while you’re pregnant. But speaking with an OBGYN can help you plan for those challenges and develop workable and practical solutions. 

When you get sick, your baby gets sick, too. So, in a very real way, your immune system is protecting both you and your baby. Your OBGYN’s goal will be to get your immune response–all those white blood cells–working as normally as possible. 

Keeping an Eye on Your Immune System

Researchers and doctors are still developing diagnostic criteria to make it easier to detect normal and abnormal immune responses. What’s important for most mothers, however, is that you get your sleep, take your vitamins and minerals, and stay active–keeping your immune system as healthy as possible. 

If you have questions about your immune system during pregnancy, contact our Wilmette or Glenview offices to make an appointment!