So, your LMC has advised you to avoid certain foods during pregnancy, to minimise the risk of contracting listeriosis (more on that later). However, your mother swears she ate whatever she wanted while she was pregnant, and YOU turned out okay. What do you do? Who do you believe? When the pregnancy cravings kick in, it can seem really tempting to give in to just one piece of sushi, or the occasional ham sandwich. Could it hurt? Probably not. Listeriosis is not as common as the food safety pamphlets would have you believe; In 2005, for example, the Auckland District Health Board recorded only eight cases of listeriosis, compared to more than 4000 cases of campylobacter and hundreds of cases of salmonella and giardia. But the problem with listeriosis is that if you DO contract it, the consequences can be dire for your baby.
For people with healthy immune systems, contact with the listeria bacteria isn't a big deal, it rarely causes illness. But during pregnancy the immune system operates at a lower level than normal, in part to stop our bodies rejecting our unborn babies. A consequence of this is that pregnant women are then more susceptible to infections, so if she comes in contact with the listeria bacteria, she's more likely to become ill with listeriosis than if she wasn't pregnant.
It's also possible for the listeria bacteria to cross the placental barrier to your baby, even without it causing you any symptoms. You might not even know you have it, but it can cause miscarriage or stillbirth. So whilst the total risk of contracting listeriosis might be low, it is worth looking at that risk in the context of "what if?" It might seem like forever, but in reality your pregnancy is just a few short months, and if avoiding certain foods can minimise the risk to your baby, isn't that worth it?