PFS013, January 2017

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Listeria and Pregnancy

Listeria and Pregnancy

Listeriosis is a foodborne illness caused by a bacterium called Listeria monocytogenes. Pregnant women are 20 times more likely to get listeriosis than the general population. Older adults and people with weakened immune systems also are at greater risk. Although listeriosis usually causes only mild, flu-like illness in a pregnant woman, it can be life-threatening for her fetus. In more serious (but rare) cases, it can lead to death in a pregnant woman. It is important to contact your obstetrician–gynecologist (ob-gyn) or other health care professional if you have signs and symptoms of listeriosis and have eaten food within the past 2 months that may have been contaminated with Listeria.

Food Poisoning in Pregnant Women

Food poisoning is an illness caused by eating or drinking harmful microorganisms that may cause stomach pain, vomiting, and/or diarrhea. Pregnant women can get food poisoning just like anyone else. In fact, pregnancy causes changes in your immune system that can make you more likely to get a foodborne illness than other healthy adults. Your fetus’s immune system also is not fully developed. For these reasons, food poisoning in a pregnant woman can cause serious problems and may become life threatening for both you and your fetus. Vomiting and diarrhea can cause your body to lose too much water and can disrupt your body’s chemical balance. If you have symptoms of food poisoning, contact your ob-gyn or other health care professional right away. Listeriosis is one of the most serious types of food poisoning.

The Bacterium That Causes Listeriosis

The bacterium Listeria monocytogenes is found in soil and water as well as in some animals, including cattle and poultry. When eaten, the bacterium can cause listeriosis. Listeria can be found in raw milk and foods made from raw milk, like certain cheeses. Listeria also can be found in food-processing plants, where it then can contaminate processed foods. The bacterium can even grow in the refrigerator. Cooking and pasteurization are the only ways to kill Listeria.

Symptoms of Listeriosis

Listeriosis usually causes only mild, flu-like symptoms such as fever, chills, muscle aches, and diarrhea or upset stomach. You also may have a stiff neck, headache, confusion, or loss of balance. Many pregnant women have no symptoms at all, and symptoms may appear as late as 2 months after exposure. But even if you do not feel sick, you can pass the infection to your fetus. Therefore, it is important to take steps to prevent listeriosis.

How Listeriosis Can Affect Your Baby

Listeriosis can lead to serious complications for your fetus. It can cause miscarriage, stillbirth, or preterm labor. Babies born with listeriosis may have serious infections of the blood or brain. It also can cause lifelong health problems for your baby, including intellectual disability, paralysis, seizures, blindness, or impairments of the brain, kidney, or heart.

If You Think You May Have Listeriosis

If you think you have eaten food contaminated with Listeria and you have any of the symptoms of listeriosis—especially a fever—contact your ob-gyn or other health care professional right away. Remember that it can take 2 months for symptoms to appear. You may have a blood test to see if you have any infection. You may need to take antibiotics to treat the infection and protect your fetus.

If you have eaten food that has been recalled because of a Listeria outbreak but you do not have signs and symptoms, let your ob-gyn know. If you develop symptoms over the next 2 months, contact your ob-gyn as soon as possible.

Preventing Listeriosis

To help prevent listeriosis, avoid eating the following foods while you are pregnant:

  • Unpasteurized milk and foods made with unpasteurized milk, including soft cheeses such as feta, queso blanco, queso fresco, Camembert, Brie, or blue-veined cheeses unless the label says “made with pasteurized milk.”
  • Hot dogs, luncheon meats, and cold cuts unless they are heated until steaming hot just before serving.
  • Refrigerated pate and meat spreads
  • Refrigerated smoked seafood
  • Unwashed raw produce such as fruits and vegetables

Avoid all raw and undercooked seafood, eggs, meat, and poultry while you are pregnant. Do not eat sushi made with raw fish (cooked sushi is safe).

General Food Safety

While you are pregnant, it is important to follow food safety guidelines to protect yourself and your fetus from foodborne illness. Follow these four steps for food safety:

  1. Clean
    1. — Wash your hands with soap and warm water for at least 20 seconds before and after handling raw food, using the bathroom, changing diapers, or handling pets.
    2. — Wash fruits and vegetables under running tap water before eating, peeling, cutting, or cooking.
    3. — Do not rinse raw meat or poultry before cooking. While many people may think this is a good idea, it actually can spread bacteria to other kitchen surfaces.
    4. — Keep your kitchen clean. Wash your utensils, countertops, and cutting boards with soap and hot water after handling and preparing foods. You can sanitize them by applying a solution of 1 tablespoon of unscented liquid chlorine bleach per gallon of water. Allow the surface to air dry. When cleaning surfaces, use paper towels. If you prefer cloth towels, wash them often with hot water in your washing machine.


  2. Separate
    1. — Keep raw meat, poultry, eggs, and seafood and their juices away from food in your shopping cart, grocery bags, and refrigerator.
    2. — Use one cutting board for raw meat, poultry, and seafood, and one cutting board for ready-to-eat foods such as fruits, vegetables, and breads.
    3. — Never put cooked food back on the same plate that previously held raw food unless the plate has been washed in hot, soapy water. Do not use sauce used to marinate raw food on cooked food unless it is boiled first.


  3. Cook
    1. — Use a food thermometer to ensure that meat, poultry, seafood, and eggs have reached a safe minimum temperature inside.
    2. — Place the food thermometer in the thickest part of the food, away from bone, fat, and gristle.
    3. — If you are using a microwave oven to cook, you should cover, stir, and rotate the food to make sure it is cooked evenly. Allow for standing time before you check the temperature with a food thermometer.


  4. Chill
    1. — Keep your refrigerator at 40° F or below and the freezer at 0° F or below.
    2. — Thaw food in the refrigerator, microwave, or in cold water. Cook food immediately if thawing in the microwave or cold water.
    3. — Do not leave food at room temperature for more than two hours (one hour when the outside temperature is above
      90° F).
    4. — Meat and poultry defrosted in the refrigerator may be refrozen before or after cooking. If thawed in the microwave or cold water, cook before refreezing.
    5. — Only buy eggs from a refrigerator or refrigerated case. Store eggs in the refrigerator in their original carton and use with in 3–5 weeks. For other cold food storage time limits, see
    6. — When selecting precut produce, choose only those items that are refrigerated or surrounded by ice and keep refrigerated at home to maintain both quality and safety.

Fast Facts About Listeriosis

  • Pregnant women are 20 times more likely to get listeriosis than other healthy adults.
  • Listeriosis can cause serious complications for the woman and her fetus.
  • The incubation period is 3–70 days, and the illness can last from days to weeks.


Antibiotics: Drugs that treat certain types of infections.

Bacterium: A one-celled organism that can cause infections in the human body.

Fetus: The stage of prenatal development that starts 8 weeks after ferilization and lasts until the end of pregnancy.

Immune System: The body’s natural defense system against foreign substances and invading organisms, such as bacteria that cause disease.

Incubation Period: The time between exposure to an infection and the appearance of signs and symptoms.

Listeriosis: A type of food-borne illness caused by bacteria found in unpasteurized milk, hot dogs, luncheon meats, and smoked seafood.

Microorganisms: Life forms, such as bacteria, that are invisible to the naked eye and that can only be seen with a microscope.

Miscarriage: Loss of a pregnancy that occurs in the first 13 weeks of pregnancy.

Obstetrician–Gynecologist (Ob-Gyn): A physician with special skills, training, and education in women’s health.

Pasteurization: The process of heating certain foods to a specific temperature for a set period of time to kill harmful bacteria.

Preterm: Born before 37 completed weeks of pregnancy.

Stillbirth: Delivery of a dead baby.

PFS013: Designed as an aid to patients, this document sets forth current information and opinions related to women’s health. The information does not dictate an exclusive course of treatment or procedure to be followed and should not be construed as excluding other acceptable methods of practice. Variations, taking into account the needs of the individual patient, resources, and limitations unique to the institution or type of practice, may be appropriate.

Copyright January 2017 by the American College of Obstetricians and Gynecologists. No part of this publication may be reproduced, stored in a retrieval system, posted on the Internet, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from the publisher.

American College of Obstetricians and Gynecologists
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