Yes. Listeria infection during pregnancy can affect both the pregnant person and the developing baby. The infection may cause miscarriage, stillbirth, early delivery, or a serious infection in a newborn. A pregnant person may have only a fever or flu-like symptoms, and some have no symptoms. The illness is uncommon, but avoiding higher-risk foods and contacting a clinician after a possible exposure can help protect the pregnancy.
What Is Listeria, and How Can It Affect Pregnancy?
Listeria monocytogenes is a type of bacteria found in soil, water, and some animals. It can contaminate food and cause an infection called listeriosis. People can become infected by eating contaminated foods, including certain dairy products, ready-to-eat meats, and unwashed produce. Unlike many other foodborne bacteria, Listeria can grow at refrigerator temperatures, so keeping food cold does not always prevent it from multiplying.
According to the American College of Obstetricians and Gynecologists (ACOG), pregnancy increases the risk of developing listeriosis compared with being a healthy adult who is not pregnant. The infection can reach the developing baby during pregnancy, even when the pregnant person does not feel very ill. This is why food safety and prompt medical advice after a possible exposure are particularly important.
What Problems Can Listeria Cause During Pregnancy?
The effects of listeriosis depend on whether an infection occurs and how it affects the pregnancy. Some people experience only mild illness, while an infection involving the pregnancy can have serious consequences for the baby. A pregnant person may feel relatively well even when the infection has affected the developing baby.
According to the Centers for Disease Control and Prevention (CDC), Listeria can spread to the baby during pregnancy and cause harm. Possible complications include:
- Miscarriage: Infection can lead to pregnancy loss, including when it occurs earlier in pregnancy.
- Stillbirth: In some cases, infection can result in the loss of the baby later in pregnancy.
- Preterm birth: Listeriosis can cause labor and delivery before 37 completed weeks of pregnancy.
- Newborn infection: A baby may develop a serious infection affecting the blood or brain around the time of birth.
Newborns affected by listeriosis may need hospital treatment. Serious infections can also lead to lasting health problems or death. These outcomes are not inevitable after food exposure; they are possible complications of an actual infection during pregnancy.
What Are the Symptoms of Listeria During Pregnancy?
Listeriosis during pregnancy may feel like a mild flu or another common illness. Some pregnant people have no noticeable symptoms. Because the initial symptoms can be subtle, it is important to consider a possible food exposure when discussing an unexplained illness with a healthcare professional.
The CDC's guidance on Listeria symptoms identifies the following experiences among the symptoms that may occur:
- Fever or chills
- Muscle aches and unusual fatigue
- Headache
- Nausea, vomiting, or diarrhea
- A general feeling of being unwell, similar to having the flu
These symptoms are not specific to Listeria and can occur with many other illnesses. Their presence does not establish the cause, and the absence of symptoms does not always rule out infection during pregnancy.
How long after exposure can symptoms appear?
Symptoms may begin within days or weeks after eating contaminated food. In some cases, they can take up to two months to appear. Therefore, someone who initially feels well after eating a recalled food may still need to pay attention to new symptoms during the following weeks. If symptoms develop after a known or suspected exposure, contact an obstetrician or another healthcare professional promptly, even if the original meal was eaten some time ago.
What Should You Do If You Ate Food That May Contain Listeria?
Eating a potentially contaminated food does not automatically mean you have an infection. However, pregnancy is a reason to take a known exposure seriously, particularly if the food has been recalled or linked to a confirmed outbreak.
Contact your obstetrician or maternity care team if you learn that you ate a recalled food or a food linked to a Listeria outbreak. Explain what you ate, when you ate it, and whether you have developed any symptoms. If you have a fever, muscle aches, unusual fatigue, or other flu-like symptoms after a possible exposure, seek medical advice promptly rather than waiting for the symptoms to become more noticeable.
The CDC's clinical guidance for managing Listeria exposure states that testing and treatment are generally not recommended for people at increased risk who have eaten a recalled product but have no symptoms. A healthcare professional can apply this guidance to the details of your exposure and advise you on what to do next. Do not start antibiotics on your own.
How Is Listeria Diagnosed and Treated During Pregnancy?
When listeriosis is suspected, a healthcare professional considers the possible food exposure, symptoms, medical history, and timing of the illness. Blood cultures, which test a blood sample for bacteria, may be used to confirm an invasive Listeria infection. Other tests may be appropriate depending on the clinical situation.
If listeriosis is diagnosed or strongly suspected, antibiotics may be needed. The choice of treatment and whether hospital care is required depend on the person's condition and the likelihood that the infection has affected the pregnancy. Prompt assessment matters because treatment may help address the infection and reduce the risk of complications for the pregnant person and baby.
Someone who has eaten a potentially contaminated food but feels well does not usually need automatic testing, antibiotics, or additional fetal monitoring solely because of that exposure. These decisions should be made with a healthcare professional based on the circumstances.
How Can You Reduce the Risk of Listeria During Pregnancy?
Food safety precautions can lower the chance of exposure. The CDC's safer food choices guidance for pregnant people recommends choosing safer alternatives to foods that are more likely to carry harmful bacteria and following good food-handling practices.
Choose safer foods
- Unpasteurized milk and dairy products: Avoid raw milk and foods made from unpasteurized milk. Choose pasteurized dairy products.
- Hot dogs and deli meats: Eat these only after reheating them until steaming hot immediately before serving.
- Refrigerated pâté and meat spreads: Avoid refrigerated versions; choose safer shelf-stable alternatives where appropriate.
- Refrigerated smoked seafood: Avoid refrigerated smoked fish unless it is cooked in a dish until steaming hot. Shelf-stable alternatives that do not require refrigeration before opening may be safer choices.
- Unwashed fruit and vegetables: Rinse fresh produce thoroughly under running water before eating, peeling, or cutting it.
- Raw or undercooked animal products: Avoid raw or undercooked meat, poultry, seafood, and eggs during pregnancy.
Soft cheeses require particular attention. Choose products made with pasteurized milk, and follow pregnancy-specific advice for individual cheese varieties. Some fresh, soft cheeses may still need to be avoided unless heated, depending on the product and local food safety guidance.
Follow safe food-handling practices
Good food preparation and storage habits can reduce exposure to Listeria and other foodborne germs:
- Wash your hands with soap and water before preparing food and after handling raw meat, poultry, seafood, or unwashed produce.
- Clean countertops, utensils, cutting boards, and other surfaces that come into contact with raw foods.
- Keep raw meat and its juices separate from ready-to-eat foods.
- Cook food thoroughly and reheat ready-to-eat foods that require heating until steaming hot.
- Refrigerate perishable foods promptly and follow storage instructions and use-by dates.
- Check food recalls and public health alerts, especially when pregnant.
Remember that refrigeration alone does not kill Listeria. Cooking food thoroughly and choosing pasteurized products are important ways to reduce the risk of infection.
When Should You Contact a Healthcare Professional?
Contact your obstetrician or maternity care team promptly if you develop a fever or flu-like symptoms after eating food that may have been contaminated with Listeria. Do not wait for symptoms to become severe before seeking advice. If you have a known exposure but no symptoms, contact your care team or follow public health instructions to determine whether any follow-up is needed.
Seek urgent medical assessment if you develop concerning symptoms such as a severe headache with a stiff neck, confusion, or difficulty maintaining your balance. These symptoms can indicate a serious illness and should not be ignored.
Most importantly, exposure and infection are not the same thing. You do not need to assume that your pregnancy has been harmed because you ate a food that might carry Listeria. Taking sensible food safety precautions and getting individualized medical advice when appropriate can help you make informed decisions throughout pregnancy.