During pregnancy, it's important to eat the right foods. This is true not only because a healthy diet helps provide both you and your baby with the nutrients you need to support your cellular processes, but also because avoiding certain foods helps prevent risk of exposure to toxins and bacteria that can damage a developing baby. Mussels are safe during pregnancy under certain conditions.
There are two reasons it's important not to expose yourself to sources of bacteria during pregnancy. The first is that your immune system is much less active during pregnancy -- this helps keep your cells from attacking your growing baby, explain Drs. Michael Roizen and Mehmet Oz in their book "You: Having A Baby." The second reason is that some bacteria can cross the placenta and damage or kill a developing fetus.
Shellfish can be a source of many vitamins and minerals, as well as protein, but they also have the potential to harbor dangerous bacteria. One of the most common bacteria in clams, oysters, mussels, and other shellfish is Vibrio vulnificus, which is a rod-shaped bacterial species capable of surviving in the high-salt environment of seawater. Vibrio is a common cause of food poisoning from eating raw or undercooked shellfish, explains the consumer information site SafeOyster.org.
Infection With Vibrio
It's not known whether the Vibrio bacteria can cross the placenta, but there are many other species of bacteria responsible for food poisoning that can cross, meaning it's best to avoid any possible risk of Vibrio infection. In normal, healthy adults, Vibrio causes gastrointestinal symptoms including diarrhea and nausea, but in pregnant women -- due to their suppressed immune systems -- Vibrio infection can be much more serious.
Mussels typically aren't eaten raw, meaning that they're less likely to be a source of infection or food-borne illness than raw shell. Still, AmericanPregnancy.org cautions that if you're going to eat mussels, you need to ensure that they're well cooked. To be safe, cook mussels and other shellfish until their shells open, and discard any mussels that don't open on their own during cooking.
With the caveat that mussels must be well cooked, they're actually very good sources of several important nutrients, explains a 1990 article in the "Journal of the American Dietary Association." Like many other shellfish, they're high in protein and the mineral zinc. They're also quite high in iron, which you need during pregnancy to increase your blood volume. Finally, mussels are low in fat, making them heart-healthy.