What not to eat when you’re expecting? Essential guidance for every mum-to-be

From the moment of conception, motherhood begins – and with it a greater level of responsibility. It’s no longer enough to look after your own physical and emotional wellbeing; you’re also creating the healthiest possible environment for the tiny life growing in your womb.

Ideally, even before starting a family, it helps to keep your body in the best condition you can – cutting out harmful habits, eating well, managing stress, and ensuring you get the right nutrients.

In this article we focus on safe eating in pregnancy and the foods to avoid. We can assess what we eat both for health effects and food-safety rules. Both matter, but food safety and correct preparation are arguably most crucial to avoid infections that could harm your baby.

Which foods should we avoid during pregnancy? 

• Alcohol can reach the foetus and cause serious developmental problems – even in small amounts.

• High-mercury sea fish can expose your baby to cellular and neurotoxins. To still benefit from omega-3 fatty acids, choose freshwater fish or sea fish known to be low in mercury.

• Caffeine remains debated. Current advice generally allows 1–2 small cups of coffee (about 100 ml each) a day, with modest amounts of green tea and dark chocolate. Remember that cola and energy drinks can also contain caffeine!

Why can certain foods or ingredients be risky? 

During pregnancy, your immune system runs a little less aggressively, so it offers less protection against pathogens. That’s risky not only for you but also for your baby, as harmful agents can cross the placenta and cause illness, preterm birth or even miscarriage.

Some foods may contain microbes or compounds that are unsafe in pregnancy, so pay attention to selection, storage and thorough cooking. Which pathogens are we most likely to meet – in pregnancy and beyond?

Salmonella – most often spread via animal products 

This bacterium is transmitted via animal faeces, so the main culprits are raw poultry and raw eggs – well known risks – but contamination can also come from fruit and veg, ready-made foods and bagged salads. Typical symptoms include vomiting, diarrhoea, fatigue, severe tummy cramps and sometimes fever – though some cases are symptom-free.

You can encounter Salmonella any time. The best prevention is thorough heat treatment – the food’s core should reach 75 °C for at least 2 minutes – plus careful toilet and hand hygiene.

Listeria – linked to a wide range of foods 

Illness occurs when enough bacteria enter the body. The bad news? While Salmonella growth slows below +4 °C, Listeria can still multiply in the fridge, so it’s best to avoid long-stored foods in pregnancy, childhood, older age or if you’re unwell.

Listeriosis can be severe – or pass without obvious symptoms. In pregnancy it can cause preterm birth or miscarriage; in newborns, sepsis and meningitis/encephalitis. It’s unpredictable and dangerous, so avoidance matters.

Higher-risk foods include:

• Raw or undercooked meats, smoked or raw fish and dishes containing them (e.g., some Japanese foods), seafood, smoked sausages/salamis, ham, hot dogs, pâté

• Unwashed fruit and veg, and raw salads

• Frozen vegetables if eaten without cooking

• Unpasteurised milk and products made from it

• Ice creams

• Soft cheeses (feta, brie, camembert, mozzarella)

• Buffet-style cold dishes (stuffed eggs, ham rolls, mayonnaise-based salads)

• Ready-to-eat chilled products

Norovirus – sudden, heavy fluid loss 

A very common gastrointestinal virus causing profuse vomiting and diarrhoea. It spreads via droplets and contact. The main danger is rapid dehydration, which is particularly risky in pregnancy. Help prevent it by washing fruit and veg thoroughly and drinking safe water when travelling. Freezing does not kill viruses, so don’t eat frozen fruit raw.

Toxoplasma gondii – a parasitic infection H3

Toxoplasmosis is well known among mums-to-be, often linked to pet care (especially cats) and the questions that come with it. The good news: a test can show whether you’re currently infected or have past immunity. Antibodies are key – they provide protection against reinfection.

You can encounter T. gondii in raw or undercooked meats, unpasteurised milk/dairy, unwashed fruit and veg, and via cat faeces. Even if mum has no symptoms, the foetus can be harmed. Stay safe with careful food prep and sensible pet-care routines.

This condition warrants special attention – it can seriously harm the baby at any trimester, yet the risks can be reduced through precautions and available tests. We’ve dedicated a full article to it – please have a read: understanding toxoplasmosis

Campylobacter – another common cause of illness 

If poultry or milk aren’t properly heated, campylobacteriosis can cause problems at any stage of pregnancy. Symptoms include stomach cramps, fever, diarrhoea and dehydration.

Prevention: cook and reheat foods thoroughly, boil raw milk, keep raw ingredients separate, wash hands often, and reheat leftovers until piping hot (pathogens can survive otherwise).

Simple steps to prevent foodborne infections 

• Wash hands with soap before and after food prep, and dry with a clean towel. Replace washing-up sponges regularly; use separate cloths for different surfaces. Keep pets away from the kitchen and food.

• Defrost frozen foods in the fridge so the warmed outer layers don’t allow pathogens to multiply. For speed, use the microwave – the key is not leaving foods at room temperature for hours. Never refreeze partially defrosted meat.

• When reheating leftovers, heat right through until steaming hot. If you plan to store leftovers, don’t taste them first – saliva can introduce microbes that then multiply.

• Do not rinse raw poultry under the tap – splashes can spread bacteria around the kitchen. Use separate chopping boards for meat and veg.

• When travelling, check that food and tap water are safe, and choose thoroughly cooked dishes in restaurants.

Sources:

NHS — Foods to avoid in pregnancy.

Food Standards Agency — Advice for pregnant women on ready-to-eat cold-smoked and cured fish.