Listeria in Pregnancy: Symptoms, Risks, Treatment & Prevention

Listeria During Pregnancy

Listeria is a serious infection that can be dangerous to the foetus during pregnancy. Although it is a rare disease, the primary threat to the pregnant mother is its devastating effect on the baby which includes developmental problems, miscarriage or foetal death. Listeria can be prevented by good personal hygiene, and its onset can be curbed by early diagnosis and intervention.

What Is Listeriosis?

Listeriosis is an infection caused by the Listeria monocytogenes bacteria which is found in soil, water, dust, animal faeces, processed foods and raw meat. It is a rare infection that most commonly occurs by eating food that is contaminated by bacteria. For the majority, listeriosis is a mild illness that can be cured with antibiotics and passes without any severe complications. However, in newborns, the elderly and people with weak immune systems, Listeria can cause meningitis, blood infection and other complications that can be potentially life-threatening. Listeria infection in pregnancy can cause complications to the foetus which can be devastating and even lead to severe disease that can be fatal.

What Are the Odds of Getting Listeria While Pregnant?

Although listeriosis is a rare infection, it is 20 times more common in pregnant women when compared to the general population. Of the total cases of infection in the population, an estimated 27% of the cases are pregnant women. Pregnancy increases the risk of listeriosis due to the changes in the mother’s immune system. When it is focusing more on defending the foetus, the mother becomes susceptible to infections.

Listeria Symptoms in Pregnancy

The symptoms of listeria may start between two days to even two months after exposure to the bacteria. Healthy adults and women who are not pregnant typically do not show any symptoms at all.

The symptoms of the infection are similar to flu with fever and muscle pain that is typical of any infection.

Symptoms in pregnant women include:

  • Fever
  • Chills
  • Muscle pain
  • Headaches
  • Nausea and vomiting
  • Confusion
  • Stiff neck

Listeria symptom: stiff neck

Who Is Most At the Risk of Getting Listeriosis

Women who have certain conditions have a slightly higher risk of infection. Pregnant women have a significantly higher risk of listeriosis compared to the general population. Some of the conditions that make women susceptible to listeriosis are:

  • Diabetes
  • Human immunodeficiency virus (HIV) infection
  • Use of steroids
  • Weakened immune system
  • Use of medicines that are immunosuppressive
  • Alcoholism
  • Cancer

How to Test for Listeria in Pregnancy

Some women show no symptoms, and some can develop it within 2 to 30 days, or longer. Since infections by eating food contaminated by listeria bacteria in pregnancy are the most common, the symptoms of that normally appear within 48 hours.

It can be roughly said that listeria is a kind of food poisoning that can cause complications in pregnancy. Hence if you’ve eaten some food recently that you suspect might be contaminated and if you are showing symptoms of the disease the doctor would order a listeria blood test during pregnancy. Cultures can take up to two days to grow. Due to the seriousness of the disease to the foetus, treatment might be started even before the results are out.


Listeria can be treated using antibiotics. In most cases, the antibiotics work well and prevent the spread of the infection to the foetus. Newborn babies can also be treated with the same antibiotics.


The mother will be given an intravenous antibiotic that treats the infection and may also help protect the baby. Since listeria and pregnancy is a combination known to cause birth defects, the baby will be monitored periodically using ultrasound scans to check for developmental problems.


Pregnant women who are infected with listeriosis have complications such as:

  • Miscarriage
  • Premature delivery
  • Stillbirth
  • Low birth weight in newborns
  • Foetal death

The infection can also affect pregnant mothers in some cases and cause:

  • Bacterial meningitis (which is an inflammation of the tissues surrounding the brain)
  • Septicemia (Blood poisoning)

What Is the Outlook?

The effects of listeriosis can be severe on babies and also has a fatality rate of 20 to 30 per cent. Early diagnosis and treatment with antibiotics can help avoid infection reaching the foetus and avert complications. However, it should be noted that not all babies that are born to infected mothers have problems.


Preventive measures can help avoid your chances of an infection. Here are some noteworthy ones:

1. Cook All Meat Thoroughly

  • Meat such as poultry, fish, pork and others must be cooked thoroughly.
  • Use a food thermometer to ensure the right temperature.
  • 70 to 82 degree Celsius is the minimum temperature at which all meat must be cooked.
  • Cook meat until it is no longer pink in the middle and fish until it is opaque.
  • Avoid sampling the meat before it is done.

2. Thoroughly Reheat Leftover Food

  • Listeria bacteria contamination can occur even after the food has been cooked. Since they can survive sometimes and continue to grow even under refrigeration unlike many other bacteria, all previously cooked food must be reheated before storage.
  • Food should also be reheated to 75 degrees Celsius or steaming hot before consumption.

3. Avoid Deli Foods Unless They Are Heated Thoroughly

  • Delis, cold cuts, meat spreads, smoked or pickled fish; refrigerated pates are all listeria foods to avoid in pregnancy. Since they have the highest chances of spreading the disease, they should only be consumed if they are cooked well until steaming hot.
  • Avoid any meat-based preparation that has been stored or refrigerated improperly.

4. Do Not Consume Unpasteurized (Raw) Milk

  • Avoid drinking raw milk whether it is from a cow, goat or buffalo. Also, avoid food prepared using unpasteurized milk.
  • Avoid soft cheese such as camembert and brie. Also avoid Mexican cheese such as Blanco, queso, panela or queso fresco unless the label states clearly that they are made from pasteurized milk.
  • Cultured dairy products such as yoghurt and buttermilk are generally considered safe. So is cottage cheese, cream cheese, hard cheese and processed cheese.
  • Ensure to read the label on all dairy products to make sure they are made out of pasteurized milk to be on the safe side.

5. Thoroughly Wash All Produce

  • All your fruits and vegetables must be washed thoroughly before consumption.
  • When in doubt peal all fruits to be safe.

woman washing fruits and vegetables

6. Avoid Raw Sprouts

  • Try not to consume raw sprouts until after your pregnancy.

7. Avoid Contamination of Food That’s Ready to Eat

  • Wash utensils, cutting boards, dishes, counters and your hands with soap water after handling potentially contaminated food.
  • Keep potentially contaminated foods such as unwashed produce, poultry, uncooked meat etc. away from clean cooked food that is ready to eat.

8. Cleanse Sponges and Dishcloths Routinely

  • Sponges and dishcloths are a potential breeding ground for bacteria.
  • Clean them with hot water and soap regularly or in the microwave or the dishwasher
  • Wipe clean dishes, utensils and countertop dry with a clean dishtowel or paper towel regularly.

9. Don’t Keep Perishable Food Around Too Long

  • Consume ready-to-eat and perishable foods as soon as possible once you’ve opened their packaging.
  • Their expiry date holds good only when they remain unopened. Once opened, they should be consumed soon.

10. Set Your Refrigerator Temperature to Optimal Values

  • The ideal temperature for the refrigerator is between 1 to 4 degrees Celsius.
  • The freezer is to be kept at zero or below always and use a refrigerator thermometer to monitor regularly.

By maintaining good hygiene, it is possible to prevent listeriosis and pregnancy complications.

Also Read: 22 Infections That Can Affect Your Pregnancy

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