When you're pregnant, your immune system can take a hit.
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How Does Pregnancy Affect Your Immune System?

Yes, there’s a reason you feel so icky.

If you’ve ever been sick while pregnant, you’re well aware of how picking up any little virus can make you feel like you’ve basically been run over by a truck. The lethargy, aches, pain, and downright ickiness of it all is just soul-crushing. Then, your toddler pukes their guts up, but your body skips right over those particular germs. What gives? Exactly how does pregnancy affect your immune system? As it turns out, there’s a reason why a simple cold can make you feel like you’ve been attacked by a herd of antelope, but then other days you feel just like Superwoman.

“During pregnancy, the immune system changes in order to provide protection for both the mother and the baby from disease,” obstetrician Neely Elisha, D.O., with Inspira Medical Group tells Romper. “Some parts of the immune system are enhanced while others are suppressed. This balance can prevent infection in the baby without compromising the mother’s health.”

Basically, your body is in the middle of a giant give-and-take situation where your immune system is concerned throughout pregnancy. “Most notably, the mother’s immune system is suppressed so that her body does not identify the fetus as a foreign entity and attempt to reject the baby,” Elisha explains.

How Your Immune System Changes During Pregnancy

Since pregnancy impacts your entire body, the changes you experience are widespread and will change throughout gestation. The same goes for your immune system’s response to pregnancy. “It’s widely accepted that the immune system is repressed during some phases, but on overdrive in very specific ways during other phases,” doula and birthing expert Sara Lyon tells Romper. “Beyond the physiology of pregnancy, there are anatomical changes that make pregnant women more susceptible to some viral infections, like UTIs and pneumonia, both due to increased structural pressure and reduced capacity — the baby and surrounding apparatus take up a lot of room!”

During early pregnancy, a weakened immune system can make you more susceptible to some viral illnesses. “During pregnancy, the levels of estrogen and progesterone change,” Elisha tells Romper. “In the first trimester, the changes in these hormones make the pregnant woman more susceptible to infections like the flu and the common cold.”

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Similar to the rest of your body during pregnancy, experts can say for certain that your immune system undergoes a plethora of changes during pregnancy. But Lyon explains that, “like so much of the perinatal experience, we have fuzzy understanding of the immune system in pregnancy.” This is why it’s difficult during pregnancy to determine what you’ll feel like from one day to the next.

“The immune system is not a monolith — instead it’s a complicated system of chemicals and physical structures that are constantly adapting to our circumstances,” Lyon explains Romper. “With this in mind, think of the immune system like a switchboard. In pregnancy, and throughout, there is an every-changing balance of suppression and enhancement that will make each woman’s immune system both more vulnerable to some pathogens, and less vulnerable to others.”

How To Support Your Immune System During Pregnancy

To keep you and your baby safe and healthy throughout pregnancy, Elisha says it’s important to support your immune system with plenty of rest, a balanced diet, and a prenatal vitamin. “We also recommend getting vaccinated appropriately to make yourself less susceptible to infection,” she continues. “We recommend receiving the flu vaccine during flu season — December through March — and the Tdap — Tetanus, Diptheria, Pertussis — vaccine during your third trimester. Additionally, the coronavirus vaccine is safe for expecting mothers and may help pass immunity to the baby as well.”

Washing your hands, staying away from sick people, and not sharing things like utensils and drinking glasses can also help keep illness at bay and precent your immune system from taking a bigger hit during pregnancy. If you start to see signs your immune system is low during pregnancy like excess lethargy, nasal congestion, lightheadedness, or dehydration, reach out to your healthcare provider.

“Most importantly, eat well, stay active, try to keep your stress levels in check — adrenaline and cortisol are terrible for the immune system — and follow strong hygiene practices, especially when you’re around toddlers,” Lyon tells Romper.


Neely Elisha, D.O., OBGYN at Inspira Medical Group

Sara Lyon, doula, owner/director Glow Birth & Body, author The Birth Deck and You’ve Got This