Kiwi researchers have found "considerable gaps in pregnant women's knowledge" of foods that aren't safe to eat during pregnancy.
Only a quarter of the pregnant 205 women surveyed in a new University of Otago study were able to identify all the unsafe options from a list of 23 different foods.
"Three-quarters of participants incorrectly identified at least one unsafe food as safe to eat in pregnancy," the study, published in the New Zealand Medical Journal on Friday, said.
And only 13 percent of them said they'd adhered to food safety in pregnancy guidelines issued by the Ministry of Health.
"Listeria is a rare infection - we found only seven or eight infections in pregnant ladies a year in New Zealand, but it is one that has a predilection for pregnant women, and the outcomes if women do get this infection are devastating," study co-author Tony Walls told Newshub. "If a foetus or newborn baby is infected, it's a pretty awful outcome."
The average score in the questionnaire was promising however - with the participants scoring 95 percent on average, or 22 out of 23.
"Generally the knowledge of the pregnant women we interviewed was pretty good - they knew a fair bit... but often that knowledge didn't translate into safe behaviours," said Dr Walls.
Foods in the questionnaire that are unsafe for pregnant women to eat were: uncooked, smoked or ready-to-eat seafood; cakes with cream and custard; raw eggs; pate purchased from a shop; salads purchased from a shop; raw milk and cheese; soft serve ice cream; dressings like mayonnaise purchased at a cafe; soft cheeses; alcohol; sushi; cold, deli and other pre-cooked meats; and hummus.
A quarter of the women surveyed wrongly thought eating cakes and slices bought from the local bakery would be okay, and about one-in-five said the same for hummus and store-bought salads.
"[Cold meats] can be safe if they're heated until they're steaming hot, but most people don't tend to do that," said Dr Walls.
Foods asked about that are safe included dried food; cereals and pasta; home-made salads prepared fresh; pasteurised food; freshly washed fruit and vegetables; plain bread and baked goods; steaming hot pie bought from a shop; packaged ice cream; and well-cooked eggs.
Thankfully not a single participant said washed fruit and veges were a danger, but a significant number - 17 percent - wouldn't eat a hot pie while pregnant.
While only 1 percent said alcohol was safe to consume, 7.4 percent admitted indulging during their pregnancy.
Julie Bhosale, an expert in toddler and maternal nutrition, told The AM Show on Friday women's immune systems are weakened while they're pregnant, so they have to be careful what they eat.
"It means they are more prone to food-borne illnesses, and so is their unborn baby. Any raw fish, any cakes, muffins, sweets that might have custard or cream in it, salads not made at home - so made at a cafe or something like that."
Asked whether it's okay to have some forbidden treats at a baby shower for example, Bhosale said if food is prepared fresh, that's usually okay - but not if it's been sitting in a shop for hours.
"If you're making it fresh, there's a big difference."
Dr Walls said he didn't want to come across as the "food police" but it was important mums-to-be know the risks.
"I don't want to be the one telling people what they can and can't eat... but I would like people to just know these infections, even though rare, they are about - and they are 100 percent preventable if you just stick to the safe foods."