Folic acid

Take at least 400 micrograms of folic acid each day while you're trying to get pregnant, and during the first 12 weeks of pregnancy.

Folic acid reduces the risk of your baby having a neural tube defect, such as spina bifida. A neural tube defect is when the foetus's spinal cord (part of the body's nervous system) doesn't form normally.

Folic acid tablets are widely available from chemists, or you can talk to your GP about getting a prescription.

Don't worry if you get pregnant unexpectedly and weren't taking folic acid supplements. Start taking them as soon as you find out, until you're past the first 12 weeks of pregnancy.

Vitamin A

Too much vitamin A can cause foetal abnormalities.

Avoid taking supplements that contain vitamin A and avoid eating liver products such as paté. Liver contains a lot of natural vitamin A.

Alcohol

When you drink, alcohol reaches your baby through the placenta. Too much exposure to alcohol can seriously affect your baby's development.

If you're trying to conceive, or are already pregnant, the government advises that you should avoid drinking alcohol.

Caffeine

You don't need to cut out caffeine completely, but don't have more than 200mg a day as high levels can result in babies having a low birth weight, which can increase the risk of health problems in later life. Too much caffeine can also cause miscarriage. There's caffeine in chocolate, cola and 'energy' drinks, as well as tea and coffee.

The amount of caffeine in foods and drinks will vary, but each of the following contains roughly 200mg of caffeine or less:

• Two mugs of tea.
• Two mugs of instant coffee.
• One mug of filter coffee.
• Five cans of cola.
• Two cans of 'energy' drink.
• Four 50g bars of dark chocolate. Milk chocolate contains around half as much caffeine as dark chocolate.

Bacterial infections

Bacterial infections can be harmful to foetal development and even dangerous for pregnant women and their unborn babies. Taking the following the steps can help you to avoid harmful bacteria:

• Cook eggs thoroughly until the whites and yolks are solid. Avoid any foods that contain raw or lightly cooked eggs, such as home-made mayonnaise, sauces and puddings.
• Make sure that all meats are cooked thoroughly. This is especially important with poultry (such as chicken and turkey) and food made from minced meat (such as burgers and sausages). Make sure that they're very hot all the way through, and there's no trace of blood or pink meat. Treat all meat at barbecues with caution.
• Wash your hands, utensils and work surfaces after handling raw meat. It may contain bacteria, which can cause food poisoning.
• Wash fruit, vegetables and salads to remove all traces of soil.
• Heat ready meals until they're very hot all the way through. This is especially important for meals that contain poultry.

And:

• Don't eat mould-ripened soft cheese, such as brie and camembert, or blue cheese, such as stilton or Danish blue. You can eat hard cheeses (e.g. cheddar, parmesan), cottage cheese, mozzarella, and processed cheese (such as cheese spread).
• Don't eat any kind of paté, including vegetable paté, because it can contain listeria.
• Don't eat liver or liver products, such as liver paté or liver sausage, as this is a very rich source of vitamin A (which can harm your unborn baby).
• Don't eat more than two portions of oily fish a week (for example, mackerel, trout or fresh tuna), or more than four cans of tuna (around 140g per can). These contain high levels of mercury, which can harm your baby's developing nervous system.
• Don't eat marlin, shark or swordfish. These can contain high levels of mercury, which can damage your baby's developing nervous system. 
• Don't eat raw shellfish, as they can contain bacteria and viruses that can cause food poisoning.

A balanced diet

A well-balanced diet will supply all the energy and nutrients needed by you and your growing baby.Eating healthily is easier than you think.

Read more about eating healthily.