Listeria in Pregnancy: How Common Is it, and Should I Worry?

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Listeria is a well-known and talked about complication. While anyone, pregnant or not, can become sick from Listeria, it is most often concerning for expecting mothers who are already more likely to get a foodborne illness. 

It should come as no surprise that Listeria can be a very serious illness during pregnancy. Listeria can affect not only the mother but is also able to cross the placenta and affect the growing baby as well.

Though it can be serious, rates of Listeria infection are very low with less than 1% of the total US population falling ill from the bacteria each year. 

The serious nature of Listeria leaves many women with unanswered questions. I will walk you through what exactly Listeria is, how it can affect you and your baby, how to avoid it, symptoms to watch out for, and the typical treatment. 

What is Listeria?

Listeria monocytogenes is a bacteria that is known to cause foodborne illness, otherwise known as food poisoning. Listeria is found in soil and is often carried by animals, so unpasteurized animal and dairy products, as well as produce grown with contaminated water and/or soil are susceptible (source: FDA).

Ready-prepared foods, such as deli meats and salads, are also at risk. These items can pick up Listeria during processing and packaging. 

You might even remember recent recalls for cantaloupe melon, sprouts, and certain ice creams that were tied to Listeria outbreaks. 

Eating foods contaminated with this bacteria is the main way to become sick with Listeria food poisoning, also called listeriosis (sources: FDA, ACOG). 

Unlike many of the other foodborne illness-causing bacteria, Listeria is not destroyed quite as easily. Refrigeration is not enough to kill Listeria. Instead, pasteurization and thoroughly cooking foods are the best way to prevent illness (sources: FDA, APA).

fresh slices of cantaloupe melon

How common is Listeria in Pregnancy? 

Many pregnant women are warned about Listeria, but it is natural to wonder how common the infection is and what your chances of getting sick really are. 

According to the Centers for Disease Control and Prevention (CDC), pregnant women in the US are 10 times more likely to get sick from Listeria compared to non-pregnant individuals (source: CDC). 

In the UK, pregnant women make up less than 20% of annual cases (source: Public Health England). Listeriosis rates for pregnant women in Australia are slightly less, making up around 10% of total cases (source: NSW Food Authority).

Overall, listeriosis is still quite rare. Between all three of these countries, the US leads in the number of cases annually with an average of 1600 reported illnesses per year. However, this is still less than 1% of the total population (source: CDC)!

I’m Worried/Paranoid about Listeria – Should I Worry? 

During pregnancy, it can seem like an endless stream of people, from doctors to the lady at the supermarket checkout, telling you to be cautious of Listeria and food poisoning. Or maybe you have heard ‘horror stories’ online and are starting to worry.

It is natural to worry over the unknown, especially during pregnancy when so much can be new and unknown. 

While Listeria infections can be quite serious, they are also rare. Much of the media attention Listeria receives is to help you avoid accidental foodborne illness, and not due to high rates or large outbreaks. 

If you frequently find yourself worrying about foodborne illness or Listeria, it can be helpful to take a few deep breaths. Remind yourself that Listeria is relatively uncommon and that avoiding the bacteria takes only a few simple steps. 

deli meats with lettuce and tomatoes

During pregnancy, frequent worrying and high levels of stress can contribute to high blood pressure, increase your risk of having a preterm delivery, and even play a role in how your baby deals with stress later in life (sources: March of Dimes, Advances in Neurobiology).

Excessive worrying can be a symptom of other health conditions, such as anxiety. If your worrying is impacting your day-to-day life or your ability to do the activities you enjoy, please reach out to your medical provider or call your national mental health hotline.

US: 1-800-950-NAMI (6264) 

US: 1-877-726-4727

UK: 111 (if you’re worried about symptoms)

How to Avoid Listeria When Pregnant 

In order to keep yourself and your developing baby safe, it is important to take Listeria prevention seriously. Luckily, there are several simple steps that can reduce your risk of getting sick- many of them you likely already practice!

  • Reheat or cook all hot dogs, deli meats, and cold cuts until they are steaming hot.
  • Avoid meat spreads, such as pate, as well as smoked seafood unless cooked until steaming hot. 
  • Do not eat soft cheese, such as brie. Processed cheeses including cottage cheese and cream cheese are still safe.
  • Avoid unpasteurized dairy, such as raw milk.
  • Similarly, steer clear of unpasteurized juices.
  • Thoroughly wash all fresh fruits and vegetables before eating or cutting.
  • Skip prepared or ready-cut fruit and opt to slice your own at home.
  • Wash all cutting boards, knives, and kitchenware before and after use. Prepare fruits, vegetables, and ready-to-eat foods separately from raw meats to avoid cross-contamination. 

(Source: Reviews in Obstetrics and Gynecology).

How do I know if I have Listeria in Pregnancy?  

Unlike some other foodborne illnesses, symptoms of Listeria can take anywhere from several days up to 2 months to show up. Most often, women feel as though they’ve come down with the mild flu. Body aches, fever and chills, nausea, diarrhea, and headache are all typical.

More serious symptoms that can arise if listeriosis has not been treated include confusion, stiff neck, and loss of balance (sources: FDA, APA).

If you are experiencing any of these symptoms, it is best to inform your medical provider. Although other illnesses such as the flu or common cold are much more likely, they may still wish to monitor your health more closely or test you for infection. 

How to Test for Listeria During Pregnancy 

Though some tests (like pregnancy tests) can be done at home, testing for Listeria must be done at the doctor’s office. Your medical provider will likely draw a small sample of blood, but they are also able to test amniotic and spinal fluid. 

This sample is then sent to a laboratory where they will check for bacterial growth. If scientists find bacteria in the sample, they will then determine which bacteria is causing your illness- including Listeria (source: CDC). 

What Listeria Does to Unborn Fetuses 

Even though falling ill from Listeria is quite uncommon, many women are curious how the illness can affect their baby. Listeria is a serious infection for an unborn fetus or newborn baby and reading about these effects can be scary- please take care of yourself while reading. 

pregnant woman sitting on a chair

In an unborn baby, Listeria can infect the baby’s blood and/or nervous system. An infection in these areas of a still growing and developing child may lead to pneumonia, meningitis, an infection of the blood, seizures, paralysis, blindness, premature delivery, and miscarriage (source: ACOG, Reviews in Obstetrics and Gynecology). 

It is important to remember that early detection and treatment of maternal listeriosis can actually prevent the baby from becoming sick or decrease their health complications (source: APA). 

How does Listeria Cause Miscarriage? 

Listeria is able to cause such devastating effects by crossing into the blood and nervous system. In pregnant individuals, Listeria can travel to both the placenta and the uterine lining. Ordinarily, the placenta acts as a baby’s pseudo-immune system, blocking infections.

Once Listeria has reached the placenta, the weakened defense from illness makes the baby more susceptible to the bacteria. Additionally, having an affected uterine lining leads to less than optimal conditions for growing and supporting a baby in utero, and miscarriage may be more likely (source: Science Daily).

Through modern medicine, there are treatments and even ways to prevent Listeria from migrating to the placenta, however. 

Listeria Treatment During Pregnancy 

As a bacteria, antibiotics are the first line of defense against listeriosis. If your blood sample tests positive for Listeria, your medical provider will likely start you on an antibiotic regimen meant to break into the Listeria cells and destroy them.

The amount of time you need to take antibiotics depends on the severity of the illness, typically ranging from 1-6 weeks. 

In order to ensure the antibiotic is strong enough to cross the placenta and prevent or treat a fetal infection at the same time, many healthcare providers prescribe high doses of the medication (source: Reviews in Obstetrics and Gynecology). 

Has Anyone had Listeria While Pregnant? Listeria Stories 

Sometimes, despite an overabundance of caution, food poisoning finds its way to your dinner plate. 

In 2019, one woman shared her and her twins’ stories. Tressa contracted Listeria while she was pregnant with her twins. She found herself post-partum in the ICU (intensive care unit) while her twins fought the infection in the NICU (neonatal intensive care unit).

Despite a terrifying first few weeks, today the family is healthy and recovered (source: Quality Assurance and Food Safety).

There are many stories like this – many of them can be found on popular “mom blogs” and internet forums. However, remember that these aren’t moderated or reviewed, so it’s difficult to get a true picture of what happened, and why.

Since listeria is one of the more serious pregnancy complications, always speak to your health provider if you have any concerns or worries. If you have queries about any particular food, then remember you can search this site for evidence-based information at any time – just use the magnifying glass on the top right.