Which foods should you avoid in pregnancy?
The fixed no-gos are the same everywhere: raw or undercooked meat, raw fish, unpasteurised milk and its products, alcohol and high-mercury fish like swordfish. Liver is on the avoid-list in most countries too (UK: avoid). Beyond that sits a large group where the answer depends on the details: is the cheese pasteurised, has the fish been cooked, how much caffeine is in it. That's exactly what this checker is for.
Why does the advice differ by country?
Every country weighs the same risks slightly differently. In the UK a runny British Lion egg is fine, in France even pasteurised brie is off the menu, and Spain looks at your toxoplasmosis immunity for cured ham. This checker shows the advice of your country's official body, and honestly flags where countries disagree.
Which supplements do you actually need?
Folic acid is the fixed recommendation around conception in every country. For the UK: 400 µg a day, ideally from 3 months before conception until week 12, plus 10 µg of vitamin D a day. Beyond that, be careful: supplements containing vitamin A (retinol), including cod liver oil, should be avoided. When in doubt, your midwife decides, not the pharmacy shelf.