Pregnant women and their newborns are more likely to get a listeria infection, which is called listeriosis, than other healthy individuals, according to the Centers for Disease Control and Prevention (CDC). (1) And Hispanic women who are pregnant are at an even greater risk: They are 24 times more likely to be diagnosed with a listeria infection compared with other healthy adults. (1) Why are pregnant women so much more likely to develop listeriosis? Pregnancy depresses aspects of a woman’s immune system in order to prevent her body from rejecting the fetus. (2) It’s thought that this depressed immune function leaves her particularly vulnerable to harmful listeria bacteria. (3) RELATED: Why Listeria Makes You Sick Certain types of soft cheeses — including ones used in “Hispanic-style” cooking, such as queso fresco and queso blanco — are more likely than most other foods to be made with unpasteurized milk, and therefore may harbor harmful listeria bacteria. Hispanic women may be at higher risk of listeriosis because their traditional dietary habits may be more likely to include these “raw” cheeses, according to the U.S. Food and Drug Administration (FDA). (4) Other common sources of listeria infection are deli meat, uncooked or undercooked hot dogs, meat spreads, and smoked seafood. (10) RELATED: How to Prevent Listeria Infection It’s important to point out that the more severe risk of listeriosis when it comes to pregnant women is for the unborn child rather than the mother. “Severe disease in the mother is rare,” says Jennifer Hunter, MPH, DrPH, a researcher and epidemiologist who has worked with the CDC. While some women experience no symptoms at all, Dr. Hunter says that listeria in pregnancy usually causes the same mild flu-like side effects that it causes in healthy adults. The symptoms of listeria in pregnancy include diarrhea or stomachache, which may be followed by fever, headaches, and body aches. (6) Because all of these symptoms of listeriosis are common ones, and not specific to the infection, the odds are good that they’re caused by something other than listeria infection. (6) But it’s still a good idea to report symptoms to your doctor to monitor the fetus for signs it may be infected. Listeriosis is most likely to develop during a pregnant woman’s third trimester because of specific changes to her immune function that may lower her natural defenses against listeriosis. (8) Some research suggests listeria may also strike earlier and therefore could be an undiagnosed cause of miscarriage in some women. (9) “If a miscarriage happens during the first or second trimester, it’s not as likely that the cause will be evaluated in any great detail,” says Robert Buchanan, PhD, a professor emeritus in the department of nutrition and food science at the University of Maryland in College Park. “There’s a possibility that it could be related [to a listeria infection], but there are a lot of reasons for a miscarriage.” The American College of Obstetricians and Gynecologists (ACOG) has issued the following guidelines to doctors when it comes to treating pregnant women who may have been exposed to harmful listeria bacteria: (6)
If a pregnant woman believes she was exposed to listeria but has no symptoms, no testing or treatment is recommended. This is true even if a woman ate food linked to an outbreak of listeria. Women are advised to tell their doctor if they notice any symptoms within two months of eating a suspect food.If a pregnant woman has mild symptoms but no fever, her doctor could choose to do nothing — or she or he could have the woman’s blood tested for listeria. ACOG says there’s not enough data to recommend one or the other of these options. But if testing reveals that a woman’s blood contains listeria, she should receive antibiotic treatment.If a pregnant woman is exposed to listeria and has both a high fever (100.6 degrees F or above) and symptoms, she should be tested for listeriosis and, at the same time, treated with antibiotics.
RELATED: How (and When) Doctors Diagnose and Treat Listeria Infection While it’s important to take these food-safety steps, keep in mind that listeria during pregnancy is rare. Even for Hispanic women, fewer than 1 in 10,000 women will develop listeriosis. (6) Do what you can to protect yourself, but don’t let listeria-related fears keep you up at night.
