The Foods to Avoid in Pregnancy, and the Actual Reason Why

By Tina Chagoury, Clinical Dietitian · 5 min read · 2026-09-28

Lists of forbidden foods are easy to ignore when nobody explains the reason. The reason is specific, and it is not about nutrition.

Every pregnant woman is handed a list of foods to avoid, and very few are told why. The reasoning matters, because once you understand it, the list stops feeling arbitrary and becomes easy to follow.

The reason is contamination, not nutrition

Almost nothing on the standard avoid list is there because it is nutritionally poor. These are foods that may carry, or may transmit, bacteria and parasites that pose a specific risk during pregnancy.

The concern is not that the food is unhealthy. The concern is what might be living in it.

Why pregnancy specifically

Two reasons.

The immune system is modulated during pregnancy. It has to be, so that the body does not reject the pregnancy. That modulation means certain infections are both more likely to take hold and more serious when they do.

Some organisms cross the placenta. An infection that would be a bad few days for you can be considerably more serious for a developing baby.

The categories that matter

Raw and undercooked animal foods. Raw or lightly cooked eggs, undercooked meat and poultry, raw fish and raw shellfish. Cooking is what removes the risk.

Unpasteurised dairy and soft cheeses made from it. Pasteurisation is precisely the step that deals with this. Hard cheeses and pasteurised products are a different matter.

Cured and ready to eat meats, which are not cooked before eating.

Pre prepared salads, buffets and food that has been standing. The risk is time and temperature rather than the ingredients.

Unwashed fruit and vegetables, where the concern is soil contamination rather than the produce itself.

High mercury fish. This one is genuinely different. Here the concern is accumulated mercury affecting neurological development, not bacteria. Which is why the advice is to choose smaller fish rather than to avoid fish altogether. Oily fish remains valuable in pregnancy, because DHA matters for the baby's brain development.

What the heightened smell is doing

There is something elegant here. Oestrogen rises steeply in pregnancy, and with it a woman's sense of smell and taste becomes markedly sharper.

One of the leading explanations is that this exists to protect her from exactly these foods. If you can detect spoilage at a far lower threshold, you are far less likely to eat something contaminated at a time when the consequences are more serious.

Your aversions are, in a sense, part of the safety system.

What I would concentrate on instead

The avoid list is important, and it is also the easy part. It is a list of things not to do.

What matters more, and gets far less attention, is what you actually need: adequate protein, folate, choline, iodine, DHA and iron, in sufficient quantities, ideally with stores built before conception rather than after.

Avoiding the risky foods protects against a specific and relatively unlikely event. Getting the nutrients right shapes the entire pregnancy.

Do both. But do not let the avoid list absorb all your attention.

This article is nutrition education, not medical advice. Follow the specific guidance of your obstetrician and your local health authority, which varies by country.

Tina Chagoury is a licensed clinical dietitian specialising in women's hormonal health across all life stages, and the creator of the Hormone Reset Method™. Learn more and start here.