If you're pregnant, you'll want to get at least 1,000 mg of calcium each day to promote healthy bone development in your growing baby and to protect your own bones against osteoporosis, advises the National Academy of Sciences and the National Institutes of Health.
Like milk, yogurt, green vegetables and canned salmon or sardines, cheese can help you meet those calcium needs. But use caution at the deli counter: Not all cheeses are safe for pregnant women.
Soft, unpasteurized cheeses can carry a type of bacteria called listeria. For healthy adults, the risk from exposure to listeria is very low, and it typically causes mild, flu-type symptoms. For pregnant women, however, the risk is much greater. Listeria, even in fairly small doses, can cause miscarriage, stillbirth and premature delivery, explains Mary Alice Smith, a University of Georgia researcher who co-authored a 2009 study on listeria risk in pregnancy for the journal "Risk Analysis." And because of immune system changes during pregnancy, pregnant women may be as much as 20 times more likely to develop listeriosis than non-pregnant, healthy adults.
"About one-third of the annual cases of listeriosis involve fetuses or newborns," says Smith, who adds that fetal listeriosis can occur any time during pregnancy but is most common during the third trimester. Listeria's incubation period can last for up to three months, so it's also wise to avoid unpasteurized cheeses if you're trying to conceive.
In general, look for cheese that says on the label that it's made with pasteurized milk. Hard cheeses, like cheddar or Swiss, are usually safe bets, as are cottage and cream cheese.
Avoid any cheeses made from unpasteurized milk, including soft-ripened cheeses like Brie, goat, feta and Camembert; blue-veined cheeses like Roquefort and Gorgonzola; and Mexican-style cheeses like queso blanco or queso fresco. Skip cheeses made from raw milk.
Too much cheese—even if it's pasteurized—can be too much of a good thing during pregnancy, reports a review of data published in the online edition of the "American Journal of Obstetrics & Gynecology" in 2009 by Dr. Alison Stuebe, assistant professor of obstetrics and gynecology at the University of North Carolina at Chapel Hill School of Medicine. Stuebe and her colleagues found that women who ate a lot of milk products like cheese during pregnancy were more likely to gain excess weight during pregnancy, even if they stuck with low-fat dairy products. Because it wasn't clear what caused the correlation between dairy consumption and weight gain, more research is needed to understand the connection. You don't need to avoid safe cheese during pregnancy, but you should be mindful of how much you're eating.
Foods other than cheese can contain listeria, so while you're pregnant, you should also avoid hot dogs and luncheon meats, chilled pâté and meat spreads, chilled smoked seafood and other foods made with raw or unpasteurized milk. Canned or shelf-stable versions of these foods are usually OK to eat. As always, check with your pregnancy health care provider if you have specific concerns.