I remember going to the doctor’s office after my first positive pregnancy test and getting handed a long list of do’s and don’ts. There were certain things on it that I expected (like no tobacco) and even more that I did not — deli meats, raw eggs, unwashed vegetables, sushi, and on and on. As someone who loves data (and for some reason craved tuna-fish sandwiches when I was pregnant), this simple list drove me crazy.
Why are there so many food restrictions when you’re pregnant? Is deli meat off-limits for the same reason sushi is? Beyond this, are the risks to the baby or to me, or both? I decided to dive into the research to see what answers I could find. What I found helped guide my decision-making and also led me to write Expecting Better.
It turns out that not all food restrictions are created equal. So let’s run through a few of the most common food restrictions during pregnancy and what the data says, so you can feel more informed and confident in your decisions (and perhaps enjoy some sushi).
Sushi
The main concern with sushi is that raw fish could carry two particular bacteria: salmonella or campylobacter. These are both things that you want to avoid generally — they can definitely make you sick — but they are not especially dangerous in pregnancy. Both bacteria cause basic stomach-flu symptoms: diarrhea, nausea, and vomiting. It’s unpleasant, but food poisoning is not more likely during pregnancy, nor does it directly affect the fetus. (There is one variant of the salmonella bacteria that can pass to the fetus, but it’s not one that we have in the U.S.)
In other words, there’s no need for added caution here. Sushi from the gas station is not recommended, but that’s true for everyone, not just pregnant women.
Raw eggs
Similar to sushi, raw eggs can contain salmonella. While food poisoning is never fun, you are not more likely to get it during pregnancy, and there is no additional risk to you or the baby beyond the discomfort of being sick.
That said, it’s pretty easy to avoid raw eggs. But if you are someone who enjoys them in an occasional salad dressing or otherwise, there is no need for extra concern. The effects of salmonella are no worse when you are pregnant than when you are not.
Fish
Eating fish (like my beloved canned tuna) can be a concern because of mercury. Fish contain mercury, particularly bigger fish, and at certain levels that can have an impact on your fetus’s developing brain. These effects are fairly small: the data shows that the difference in mercury levels between the average American woman and the most mercury-exposed woman is enough to produce a 3.5-IQ-point difference in their children. Still, fish containing high levels of mercury are best avoided for that reason.
On the other hand, fish oils contain very high rates of omega-3 fatty acids (or DHA), which are great for a baby’s brain development. Studies show that increasing your DHA intake by 1 gram per day would increase your child’s IQ by, on average, 1.3 points. You can get DHA from other sources, sometimes even through prenatal vitamins, but fish are a good source.
If this seems somewhat contradictory, it’s because it is. So, what to do? The worst thing you can take from this advice is the idea that you should avoid fish entirely. Fish are great! In this case, you want to try to pick fish that are low in mercury and high in omega-3s, when possible. Here’s a good overview:
Deli turkey and unpasteurized cheese
The main concern with eating deli meat and unpasteurized cheese is the risk of listeria. Listeria is a foodborne bacteria that is both harmful and hard to avoid. It can be fatal even in healthy adults, and pregnant women are more susceptible to getting listeriosis. Thankfully, it’s not that common: about one in 8,000 pregnancies a year are affected. That said, the consequences are scary, with miscarriage, preterm birth, or stillbirth as common outcomes.
Part of what makes this bacteria tricky is that it’s very difficult to pin down the source of an infection. A wide variety of foods can carry listeria, but there are a couple of consistent causes. From 1998 to 2008, 10% of outbreaks identified by the CDC were traced to deli turkey. Another 17% were related to queso fresco, a Mexican-style soft cheese often made from unpasteurized milk. However, there is a long list of other culprits, including mushrooms, cantaloupe, and salad greens.
Ultimately this is something you need to decide for yourself. The question is not whether listeria infection is scary: it is. The question is what decisions you can make to avoid it. Based on past outbreaks, it’s reasonable to avoid queso fresco and, probably, deli turkey sandwiches. You can also try to pay attention to recalls and outbreaks when they happen. If you want to keep up to date, the CDC is your best bet — check out its outbreak alerts here — along with FDA recalls.
Raw or rare meat
Raw or rare meat is a restriction in pregnancy because of risks associated with a parasite called toxoplasmosis. Toxoplasmosis infection can result in flu-like symptoms or no symptoms at all. However, if you are pregnant and don’t get treatment, or don’t notice your symptoms, then your fetus can become infected and develop congenital toxoplasmosis. This affects about 1 in 1,500 babies and complications can be severe, including blindness and epilepsy.
Fortunately, avoiding toxoplasmosis isn’t that hard. It comes primarily from undercooked meats. According to a study in Europe, one-third to half of cases could be avoided by not eating raw or very undercooked meat. Doing that will dramatically limit your exposure.
Unwashed vegetables and fruit
Similar to raw or rare meat, eating unwashed vegetables and fruit can lead to toxoplasmosis infection. Based on a study in Europe, about 10% of cases could be avoided by washing vegetables and fruits well before eating them. This makes a fairly good case for washing thoroughly when possible to lower your exposure.
What if I get sick?
If you do get sick, the somewhat good news is that, for both listeria and toxoplasmosis, early treatment can reduce (though not eliminate) the chance of transmission to your baby.
If you are feeling sick, be more cautious than usual. Don’t just ride it out at home; call your doctor and let them know what’s going on.
The bottom line
- Sushi and raw eggs are fine to eat.
- Mercury in fish is a concern. You should try to pick fish that are low in mercury and high in omega-3s, when possible.
- The main concern with eating deli meat and unpasteurized cheese is the risk of listeria. Based on past outbreaks, it’s reasonable to avoid queso fresco and, probably, deli turkey sandwiches.
- To reduce your possible exposure to toxoplasmosis, avoid eating undercooked meats and wash your fruit and vegetables before eating them.
- If you do get sick, call your doctor.
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