Raw fish in sushi can carry bacteria and parasites that pose serious risks during pregnancy, particularly to your baby. The concern isn’t sushi rice or seaweed or even fish itself. It’s specifically the raw and undercooked seafood that makes certain sushi dangerous. Your immune system shifts during pregnancy in ways that make you more vulnerable to foodborne infections, and some of those infections can cross the placenta and directly harm the fetus.
The good news: cooked sushi rolls are generally safe, and eating fish during pregnancy is actually recommended for your baby’s brain development. The key is knowing which rolls to order and which to skip.
Your Immune System Works Differently During Pregnancy
To understand why raw sushi becomes risky when you’re pregnant, it helps to know what changes inside your body. During pregnancy, hormonal shifts reduce your cell-mediated immune function, which is the branch of your immune system responsible for fighting off bacteria and parasites that invade your cells. This suppression isn’t a flaw. It’s what keeps your body from rejecting the fetus, which is genetically half “foreign” to your immune system.
The trade-off is that infections you might have fought off easily before pregnancy can now take hold more readily. Foodborne pathogens that would cause a mild stomachache in someone who isn’t pregnant can lead to complications ranging from preterm labor to miscarriage. Two pathogens in particular make raw fish a concern: Listeria and parasitic worms.
Listeria Is the Biggest Threat
Listeria monocytogenes is a bacterium found in raw and undercooked animal products, including fish. For most healthy adults, a Listeria infection causes mild flu-like symptoms or no symptoms at all. During pregnancy, the stakes are completely different. Listeria has a specific affinity for placental tissue, meaning it can cross the placenta and infect the fetus directly.
The numbers are sobering. Maternal listeriosis in early pregnancy carries a 65% risk of miscarriage. At any stage of gestation, the infection can cause stillbirth or trigger preterm labor. For you, the mother, symptoms may feel like nothing more than a mild fever, body aches, or fatigue, which makes it easy to dismiss or miss entirely.
If the infection reaches the baby, the consequences depend on timing. Early-onset disease, appearing within the first six days of life, can involve respiratory distress, sepsis, pneumonia, or meningitis. Late-onset disease develops between 7 and 28 days after birth and often presents with lethargy, vomiting, or meningitis. The most severe form, a condition involving widespread inflammatory lesions across the baby’s organs, carries a mortality rate as high as 80% in preterm infants.
Listeria is particularly dangerous because it can grow at refrigerator temperatures, so standard cold storage doesn’t eliminate it the way it does for many other bacteria. Only thorough cooking kills it reliably.
Parasites in Raw Fish
Raw fish can also harbor parasitic worms, most commonly Anisakis simplex, a white, cylindrical nematode about 3 centimeters long. In humans, Anisakis larvae can’t mature to adulthood, but they can still cause acute intestinal illness, allergic reactions, and abdominal pain as the live larvae attempt to burrow into your stomach or intestinal wall.
The direct risk to the fetus from Anisakis appears lower than from Listeria. Research on mothers exposed to the parasite shows that anti-Anisakis antibodies do cross the placenta, with a clear correlation between maternal and newborn antibody levels. But the bigger practical concern is the illness itself: severe vomiting, dehydration, and intestinal inflammation during pregnancy are harmful on their own and can complicate an otherwise healthy pregnancy.
Commercial sushi fish in the U.S. is typically flash-frozen before sale, which kills parasites. The FDA requires freezing at -4°F for 7 days, or blast freezing at -31°F until solid and then holding at -4°F for 24 hours. This process is effective against parasites but does nothing to eliminate bacteria like Listeria or Salmonella.
Mercury Is a Separate Concern
Even if raw fish were safe during pregnancy, not all sushi fish would be equal. Mercury accumulates in larger, longer-lived predatory fish, and it can harm your baby’s developing nervous system. Some popular sushi choices are relatively high in mercury:
- Bigeye tuna (often served as “maguro”): averages 0.689 parts per million (ppm) of mercury, with some samples reaching 1.8 ppm
- King mackerel: averages 0.73 ppm, with samples as high as 1.67 ppm
- Spanish mackerel (Gulf of Mexico): averages 0.454 ppm
By comparison, Atlantic mackerel averages just 0.05 ppm, and salmon is consistently among the lowest-mercury fish available. The type of fish matters as much as how it’s prepared.
You Should Still Eat Fish While Pregnant
Here’s what sometimes gets lost in the “no sushi” advice: fish is actively good for your pregnancy. The omega-3 fatty acids DHA and EPA support your baby’s brain development, and fish also provides iron, iodine, and choline, all of which are critical during pregnancy. The FDA recommends that pregnant and breastfeeding women eat 8 to 12 ounces of lower-mercury seafood per week, which works out to two or three 4-ounce servings.
Skipping fish entirely during pregnancy means missing out on nutrients that moderate scientific evidence links to better cognitive development in your child. The goal isn’t to avoid fish. It’s to eat cooked, lower-mercury fish regularly.
Sushi Rolls That Are Safe During Pregnancy
You don’t have to sit out every sushi dinner for nine months. Plenty of rolls use cooked ingredients and are considered safe:
- California rolls: filled with cooked imitation crab, which is made from a paste of white fish (usually Alaska pollock)
- Cooked shrimp or eel rolls: both are fully cooked and lower in mercury
- Cooked salmon rolls: salmon is a low-mercury, high-omega-3 choice
- Vegetable rolls: cucumber, avocado, carrot, and other plant-based fillings carry no foodborne risk from fish
- Tamago (egg sushi): safe as long as the egg is firm and thoroughly cooked, not runny
When ordering, confirm that the fish in your roll is fully cooked, not seared or “lightly torched,” which may leave the center raw. If you’re at a restaurant where you’re not sure about preparation, vegetable rolls are the simplest safe bet.
What to Avoid Until After Delivery
Any sushi or sashimi featuring raw fish should be off the table during pregnancy. That includes popular choices like raw tuna nigiri, salmon sashimi, raw yellowtail, and poke bowls with uncooked fish. Ceviche, where fish is “cooked” in citrus juice, doesn’t reach temperatures high enough to kill bacteria and should also be avoided.
Beyond sushi specifically, the same logic applies to other raw or undercooked seafood: raw oysters, clams on the half shell, and smoked fish that hasn’t been heated (like lox or cold-smoked salmon). If the fish hasn’t been heated to an internal temperature that kills bacteria, the risk remains, regardless of how fresh it looks or how reputable the restaurant is.