Diet and health Heather Welford There are lots of misunderstandings about what you can and can't eat during pregnancy. Here are some suggestions for keeping you and your baby healthy.

Eating well

A good diet can help you stay fit, get in good condition for the birth and maintain your energy levels.

Aim to include in your daily diet:

• Fresh fruit and vegetables, especially citrus fruits and dark green vegetables, which contain folic acid
• Carbohydrates such as bread, pasta, grains, potatoes and cereals
• Milk and other dairy produce such as yoghurt, fromage frais and cheese - choose lower fat options where possible
• Lean meat or fish, which has high levels of essential fatty acids

Research indicates that mothers who eat fish once a week are less likely to give birth prematurely. Oily fish, which includes fresh tuna, mackerel, sardines and trout, eaten in pregnancy also helps children's eyesight. But don't have more than two portions of oily fish a week.

High levels of mercury can harm a baby's developing nervous system

Avoid eating shark, swordfish and marlin, and limit tuna to no more than two tuna steaks a week (weighing about 140g cooked or 170g raw) or four medium-size cans of tuna a week (with a drained weight of about 140g per can). This is because of the levels of mercury in these fish. High levels of mercury can harm a baby's developing nervous system.

Keep up your fluid levels, with regular glasses of water or diluted fruit or vegetable juices throughout the day. This will help keep you hydrated, which can prevent tiredness and headaches, and helps bladder and kidney health.

Can I follow a vegetarian or vegan diet during pregnancy?

If you eat a well-balanced vegetarian or vegan diet, you'll get all the nutrients you need. But if your diet isn't balanced you may need extra vitamins, for example, B12, which can be found in some manufactured goods, such as soya products, or in supplements. You may also require a vitamin D supplement.

Make sure you get enough iron in your diet as well. There's a list of iron-rich foods below.

Eating safely

• Cook meat thoroughly and wash all fruit and vegetables before eating to avoid infection with toxoplasmosis, an organism that can affect your baby.
• Avoid mould-ripened soft cheeses such as brie or camembert, and blue-veined cheeses such as stilton. All are associated with listeria, which can lead to premature birth and miscarriage. You should also avoid mould-ripened goat's and sheep's milk cheeses, such as chèvre.
• Avoid pâté, for the same reason.
• Make sure all ready-made foods are piping hot throughout before eating, as they are also a listeria risk.
• Drink only pasteurised or UHT milk, which has had harmful germs destroyed.
• Only eat eggs if they're hard-boiled or scrambled, to avoid salmonella infection.
• Don't eat liver and liver products while pregnant, as they contain high levels of vitamin A, which can be harmful to your baby.

There's some evidence that it might be safer to avoid peanuts in pregnancy and breastfeeding if your partner has a peanut allergy (if you have one you won't be eating them anyway).

There's much less evidence for avoiding peanuts if you're concerned about eczema, asthma, or other allergies. For up-to-date information about this, ask your midwife.

Food preparation

Toxoplasmosis is found in cat faeces so keep cats away from food preparation areas and if you change the cat litter tray or do any gardening wear gloves

Folic acid

Folic acid, also called folate, is a B vitamin found in a number of foods. Folic acid has been shown to reduce the risk of neural tube defects in babies, when development of the spine or brain are incomplete. Such defects include spina bifida and anencephaly.

Because it's virtually impossible to get the recommended amount of folic acid from diet alone, current advice is for all women who are pregnant or planning to become pregnant to take a 400mcg folic acid supplement until the 12th week of pregnancy. You can continue taking it after this date, but talk to your midwife or doctor about dosage.

Foods that contain folic acid include:

• Dark green vegetables
• Cereals, especially wholegrain - some breads and cereal products are fortified with folic acid (read the packet's nutritional label)
• Oranges, grapefruit, bananas
• Beans and pulses
• Milk and yoghurt
• Yeast or malt extracts (as drinks or spreads)

Folic acid supplements can be prescribed by your GP and are also widely available to buy from pharmacies and supermarkets.

Iron

Most people get all the iron they need from a balanced and varied diet but when you're pregnant, you can become deficient in iron. Iron-rich foods are:

• Meat (thoroughly cooked)
• Dark green vegetables such as broccoli, watercress, spinach and kale
• Nuts (although you may need to avoid peanuts) - almonds and brazil nuts are a good source
• Pulses such as chick-peas and lentils
• Wholegrains such as wholemeal bread, brown rice and breakfast cereals
• Dried fruit
• Eggs

Is caffeine harmful?

The Food Standards Agency suggests pregnant women limit their intake of coffee to no more than four cups a day. Remember cola drinks also contain caffeine. Switch to non-caffeine alternatives where possible.

Drinking, smoking and other substances

Pregnant women should avoid alcohol completely, the government advises, although the Royal College of Obstetricians and Gynaecologists says there's no evidence a couple of units once or twice a week will harm the baby. Binges (for example, getting drunk) are definitely to be avoided.

Continuous, heavy drinking, can cause permanent brain and developmental damage in the foetus. The greatest risk is probably in the early stages of the pregnancy, when rapid growth by the baby may be disrupted and abnormal features may develop. If you think you have a drink problem, see Support for you.

If you smoke, get help to give up. Smoking raises the carbon monoxide levels in your blood and reduces the amount of oxygen your baby gets, affecting growth and making him vulnerable to infection. It also puts him at higher risk of stillbirth or being born early.

After the birth there's an increased risk of sudden infant death syndrome (SIDS or cot death). Your partner should stop smoking too, and you should avoid smoky atmospheres.

Drugs, including cannabis and ecstasy, are risky during pregnancy as they reach the baby's bloodstream as well as yours. Heroin and cocaine can create serious dependency problems in babies. Ask your midwife or doctor for help if you need it.

Infectious diseases can be risky, too. Most women in the UK are vaccinated against rubella, so this is no longer a major issue, but you should avoid people with chickenpox, as it can cause developmental problems or stillbirth.

Your employer is legally obliged to change your job if your health is at risk because you work with poisonous chemicals or risky procedures such as x-rays.

Weight gain

Healthy eating is a priority. Don't try to lose weight while you're pregnant without medical advice. If you're pregnant, you'll gain weight.

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