Risk foods and pregnancy: what's the reality?

The ANSES guidance on dietary reference values for pregnant women sets out a list of foods to avoid during pregnancy [1].

Microbiological risks

These foods can pose a microbiological risk (and may cause food poisoning):
All raw or undercooked meats
Cooked charcuterie products requiring refrigeration (e.g. rillettes, pâtés, products in aspic)
Charcuterie products made with raw pork liver (e.g. figatelli, liver sausage), raw or undercooked pork liver 
Raw milk 
Raw milk cheeses, with the exception of cooked pressed cheeses (such as gruyère or comté) 
Soft cheeses with a bloomy rind (such as camembert, brie) and washed-rind cheeses (such as munster, pont l'évêque), grated cheeses
The National Health Service states that soft blue cheeses such as Danish blue, gorgonzola and roquefort should be avoided unless they are cooked through
Raw eggs and products made with raw or insufficiently cooked eggs 
Raw shellfish, raw fish (sushi, sashimi, tarama), smoked fish. The smoked salmon during pregnancy for example is not recommended.
Shelled crustaceans sold ready-cooked and requiring refrigeration.

Raw meat, as well as poorly washed fruit and vegetables, can carry toxoplasmosis. The national reference centre (CNR) recorded, in 2018, 151 cases of toxoplasmosis infections in pregnant women. This included 9 moderate cases at birth and 3 severe ones, 9 pregnancy terminations and 22 unknown outcomes.

For example, it is possible to have a barbecue during pregnancy, particularly if hygiene rules are properly followed and meats, fish, etc. are cooked through to the core. 

Chemical contaminants

Some fish may contain contaminants (methylmercury, toxins, etc.): 
Swordfish
Marlin
Siki
Shark 
Lamprey

These contaminants can, among other things, affect the nervous system. Methylmercury, for example, has serious effects on pregnancy; it has been linked to a risk of premature birth, low birth weight, miscarriage and congenital malformations [2]. 

When looking at the Listeria bacterium, it turns out that the risks of contamination from consuming foods deemed at risk of containing this bacterium are low. 

A low frequency of contamination

Indeed, in a study on pregnant women, researchers showed that there was 1 case of Listeria infection per 83,000 following consumption of cured meats, and 1 case per 5 million for soft cheeses [3]. 

Thus, if foods are handled and stored correctly, the risk of being infected with Listeria appears to be low. Therefore, pregnant women do not need to avoid soft cheeses or cured meats, provided they are consumed in moderation and the source of the food is safe [4].

Avoiding all foods deemed potentially at risk of infection can lead to nutritional deficiencies in many nutrients.

There is more risk in not consuming these foods than in consuming them

In a study of nearly 7,500 women who strictly followed the recommendations on avoiding foods potentially contaminated with the Listeria bacterium, researchers showed that these women were at risk of having suboptimal intakes of certain nutrients: fibre, folates, iron and vitamin E [5]. 

It is very important to ensure good nutrient intakes, and if needed, to take a pregnancy supplement to ensure your needs are covered.  

When it comes to eggs, the main contamination risk is from the Salmonella bacterium. Like other foodborne illnesses, Salmonella infection typically presents with fever and gastrointestinal symptoms such as nausea, vomiting, stomach cramps and diarrhoea. However, bacteraemia (the presence of the bacterium in the bloodstream), which occurs in approximately 4% of cases, can lead to intrauterine septicaemia, which is particularly dangerous during pregnancy [6].  

If foods considered to be at risk are not consumed, the benefits of eating them may be lost, and they may even be replaced by foods that are not necessarily good for health. 

Eating fruit and vegetables is not discouraged — in fact, it is strongly recommended. However, this food category also carries risks! Fresh leafy fruits and vegetables are implicated in 46% of food poisoning cases [20].

In the USA, researchers analysed the sources of listeria outbreaks: of the 224 people infected between 2009 and 2011, 147 fell ill after eating melon! As for salmonella, of the 5 outbreaks recorded in 2016, only 1 was linked to raw eggs — the others came from "plant" sources: sprouts and pistachios in particular.

Consuming fruit and vegetables is not without risk, but guidelines recommend eating them because the benefits outweigh the risks.

However, we advise against buying pre-cut fruit and vegetables, as they are more likely to be contaminated by pathogens [21].

If we look closely, we notice that virtually every food we eat carries some potential risk, whether we are pregnant or not. The key is to be mindful of what we eat in a sensible way!

It is strongly recommended to limit liver consumption during pregnancy, due to its retinol content (an active form of vitamin A). ANSES has set an upper safety limit of 3000 µg/day, as excess retinol can lead to congenital malformations.

However, liver does have its benefits: it is rich in B vitamins and choline !

Moreover, the Elfe study on pregnant women found that between 50 and 75% of women are deficient in vitamin A!

It is essential to avoid supplementing with retinol during pregnancy, and even before, so make sure your fertility food supplement does not contain any. 

If a food smells unusual, do not consume it. 
Pay attention to the origin of the foods you consume.
Store your raw foods appropriately.
Follow strict hygiene rules (clean work surfaces, washed hands, and take care to avoid cross-contamination between different ingredients).
For higher-risk foods, it is preferable to cook and consume them yourself — cases of food poisoning are more common when eating out.
If in doubt about a food, the simplest approach is not to consume it. 

In reality, no food is perfectly safe, and some foods considered risky can be consumed in moderation without harm, while also providing the nutrients needed for a healthy pregnancy. When looking at the benefits and risks of consuming certain foods, it actually appears that it would be better to eat them rather than avoid them.

In any case, make sure you consume quality products that have been properly stored in line with strict hygiene standards.