Ate sushi before you knew you were pregnant: what to know

What does the evidence say about ate sushi before you knew you were pregnant during pregnancy?

1. Symptoms from bacteria or parasites in raw or undercooked meat and seafood can start anywhere from hours to weeks after eating, and some people who are infected show no symptoms at all; anyone worried about a specific exposure can ask their provider whether testing makes sense. 1
2. In pregnancy-associated listeriosis cases specifically, symptoms began within 5 weeks of exposure in more than 75% of cases and within 6 weeks in 90% of cases, a notably longer window than the incubation period typically seen outside of pregnancy. 2
3. People who are pregnant are named among the groups most at risk for listeriosis, along with young children, adults over 60, and people with weakened immune systems, and the symptoms to watch for include diarrhea, fever, muscle pain, joint pain, headache, stiff neck, back pain, chills, light sensitivity, and a sore throat with fever and swollen glands. 3
4. US women become aware they are pregnant at an average gestational age of 5.5 weeks, and that average timing has not shifted in a clear direction across more than two decades of national survey data. 4
5. Cooking fish and shellfish to 145°F is the standard food-safety benchmark, and raw preparations like sushi and sashimi skip that step entirely, which is why raw fish carries more risk for Listeria and other germs than the same fish cooked through. 1

Is ate sushi before you knew you were pregnant safe in each trimester?

• First trimester. This scenario almost always lands in the first trimester, since that's the gap between conception and a positive test. A single raw-fish meal is a lower-risk exposure than repeated raw-fish meals over time, and most people in this exact situation have no symptoms at all.
• Second trimester. If listeriosis symptoms were going to follow an early exposure, they would typically show up by now: pregnancy-associated cases most often start within 5 to 6 weeks. No symptoms this far out is reassuring, though any new fever or flu-like illness is still worth a call to your provider.
• Third trimester. By the third trimester, an early exposure like this is old news clinically, and the relevant question becomes your current diet. Keep skipping raw fish for the rest of pregnancy regardless of what happened before you knew.