Diet during pregnancy

Pregnancy can be a very exciting time for most people. It can also make some people feel anxious about what they should (or should not) be doing for their own and their baby's health. The information below will answer many frequently asked questions. There are also links to further reliable sources of information at the bottom of the page.

Diet

During pregnancy it is important to continue to eat a healthy balanced diet. You may have an increased appetite but it is not necessary to 'eat for two', even if you are having twins or triplets. Too much weight gain increases your risk of developing problems later in the pregnancy. Also, extra weight is difficult to lose after the birth. According to the World Health Organization, for women with a normal pre-pregnancy weight, a weight gain of 10-14 kg over the pregnancy is associated with the lowest risk of pregnancy complications.

Aim to eat a healthy diet (which everyone should be eating, not just pregnant women).

Briefly, the bulk of most meals should be starch-based foods (such as bread, cereals, potatoes, rice, and pasta), with fruit and vegetables. Eat protein foods such as meat, fish, pulses, chicken, etc, in moderation.

Include foods with plenty of iron, calcium and folic acid: a growing baby needs these nutrients right from the start of the pregnancy:

• Iron is mainly in red meat, pulses, dried fruit, green vegetables and fortified cereals.

• Calcium is mainly in dairy products such as milk, cheese, and yoghurt. (Lowfat milk, cheeses and yoghurts usually contain just as much calcium as the full-fat varieties.)

• Folic acid is mainly in green vegetables, brown rice, and fortified cereals.

• Fish: in general, fish is a good source of protein and other nutrients. Aim to eat at least two portions of fish per week, with at least one portion being oily fish (see below).

However, there are some important exceptions. Some types of fish contain a high level of mercury which can damage the developing nervous system of an unborn baby. Because of this, the Food Standards Agency (FSA) advises:

• You should not eat any shark, marlin, or swordfish.

• Limit tuna - eat no more than four medium-sized cans (drained weight = 140 g per can) or two fresh tuna steaks per week (weighing about 140 g cooked or 170 g raw).

Also, do not eat raw fish or uncooked shellfish (which may contain germs (bacteria), viruses or parasites).

Also, some types of fish may contain a small amount of chemicals from pollution, including dioxins and polychlorinated biphenyls (PCBs). If you eat a lot of these fish, these chemicals may build up in your body over time, which may be harmful. Because of this, the FSA advises that you should have no more than two portions a week of any of the following fish:

• Oily fish, including mackerel, sardines, salmon, trout and fresh tuna. (Tinned tuna doesn't count as oily fish.)

• Sea bream, sea bass, turbot, halibut, rock salmon (also known as dogfish, flake, huss, rig or rock eel).

• Brown crabmeat.

However, the advice above (from the FSA) is controversial. Some experts think the advice to eat no more than two portions of oily fish per week during pregnancy is too restrictive, and may even be detrimental to a developing baby. For example, one study found that children of mothers who had eaten a reasonable amount of oily fish during pregnancy had, on average, better communication and social skills at age 7. Oily fish are rich in nutrients called omega-3 fatty acids. It is thought that omega-3 fatty acids are important to aid brain development and may be the reason for the results of this study.

Therefore, some experts argue that the concern over toxic chemicals in fish is overcautious and that the benefits of eating three or more portions of oily fish per week outweigh other risks. Further research may help to clarify this.

Foods and drinks to avoid

You should not eat the following if you are pregnant:

• Anything with a lot of vitamin A. You need a small amount of vitamin A to keep healthy. However, large amounts can harm an unborn baby. So, avoid:

• Liver and liver products such as liver pâté and cod liver oil supplements.

• Vitamin tablets or supplements which contain vitamin A.

• Food which may have high levels of listeria. This bacterium (germ) does not usually cause problems in people who are not pregnant. However, pregnant women are more likely to become infected with listeria, and it sometimes causes miscarriage, stillbirth, or infections in the baby after birth. Foods which are most at risk of carrying listeria are:

• Undercooked meats and eggs. This may occur in some pre-cooked meats and pre-prepared meals. Make sure all meat foods are cooked until piping hot. Eggs should be cooked until the white and yolk are solid. Avoid foods that may contain raw eggs, such as some types of mayonnaise and mousse.

• Mould-ripened and soft cheeses such as brie, Camembert and blue-veined cheeses. (Hard cheeses and processed cottage cheese are safe.)

• Pâtés - including vegetable pâtés.

• Raw shellfish and raw fish.

• Unpasteurised milk. Note: goat's milk is often unpasteurised, and goat's milk products such as cheeses are often made from unpasteurised milk.

• Certain fish (as described earlier).

• Limit the amount of caffeine to no more than 200 mg per day. Caffeine is a substance that occurs naturally in foods such as tea, coffee and chocolate; is added to some drinks such as cola, and some energy drinks; and is an ingredient of some cough and cold remedies, and some painkillers which you can buy at pharmacies. Having a lot of caffeine increases your risk of having a miscarriage and a baby with low birth weight. The increased risk is small. But, it is best to play safe. The main sources of caffeine are coffee, tea, chocolate, and cola. It is also added to some energy drinks and to some cough and cold remedies. As a rough guide:

• One mug of instant coffee has about 100 mg of caffeine.

• One mug of brewed coffee has about 140 mg of caffeine.

• One mug of tea has about 75 mg of caffeine.

• One 50 g plain chocolate bar has about 50 mg of caffeine. Milk chocolate has about half the caffeine that plain chocolate has.

• One can of cola or half a can of an energy drink has up to 40 mg of caffeine.

• Liquorice may be important to avoid. A research study published in 2009 found that women who ate a lot of liquorice (which is common in some countries) were more likely to have children with lower intelligence levels and more behavioural problems. Further research is needed to clarify this issue.

A note about peanuts: until recently, the FSA advised that you may wish to avoid eating peanuts when you are pregnant if you have an atopic disease such as asthma, eczema, or hay fever, or if a close family member has one of these conditions. This was because there was a concern that children could develop a peanut allergy as a result of their mother eating peanuts during pregnancy. However, in the light of new evidence, this advice was changed in December 2008. The FSA now advises that there is no need for women who are pregnant or breast-feeding, or who have children aged under 3, to change their diets in order to exclude peanuts.

Medication

The effects of some prescribed medicines have been well studied and it is known that certain medicines are safe in pregnancy. For example, paracetamol at normal dose is safe and useful for headaches, backache and other aches and pains that may occur during pregnancy. However, for many medicines, we do not know for sure if they are safe or unsafe. So if you are pregnant, you should minimise your use of medication. This includes medicines that you can buy. Also, just because a medicine says it is herbal or natural, it does not necessarily mean that it is harmless or safe.

Always tell a doctor or dentist who prescribes medication for you that you are pregnant.

Also, don't take medicines that you can buy over the counter (including herbal remedies) unless they are known to be safe in pregnancy. The pharmacist will advise.

• Paracetamol at normal dose is safe and useful for headaches, backache, and other aches and pains that may occur during pregnancy.

• Anti-inflammatory painkillers such as ibuprofen. You should not normally take these during pregnancy. Regular use during pregnancy may affect the large blood vessels of the developing baby.

• Laxatives. Constipation is common in pregnancy and you may need a laxative. At first it is best to try increasing the fibre in your diet and increasing the amount of non-alcoholic fluids that you drink. If this fails then fibre supplements such as bran, ispaghula and sterculia are safe. If you need something stronger, then it is best to discuss this with a doctor. Some laxatives such as docusate and lactulose may be prescribed safely for a short time.

• Antihistamines. The safest one to use in pregnancy is chlorphenamine. This is because it is the oldest, and so has a long-established safety record. However, it tends to make some people drowsy. If you require an alternative then it is best to see a doctor for advice.

• Decongestants such as pseudoephedrine, phenylephrine and xylometazoline are best avoided in the early stages of pregnancy. However, they are unlikely to be harmful if used just now and then.

If you already take regular medication, (for example, for epilepsy or diabetes), it is important that you discuss this with a doctor before becoming pregnant. If you have an unplanned pregnancy, discuss with your doctor as early as possible any medication that you take. In some cases, the risk of taking the medicine has to be balanced against the risk of not taking the medicine, and your condition not being treated.

Vitamins and supplements

Folic acid: you should take folic acid tablets (supplements). Ideally, do this from at least one month before you get pregnant, and continue taking them until at least the end of the 12th week of pregnancy - even if you are healthy and have a good diet. Folic acid is a naturally occurring vitamin found in spinach, sprouts, broccoli, green beans, and potatoes. Some bread and breakfast cereals are fortified with folic acid. However, you need a good supply of folic acid when you are pregnant to help with the development of the baby. If you take folic acid tablets in early pregnancy you reduce the risk of having a baby born with a spinal cord problem such as spina bifida. There is evidence that folic acid also reduces the risk of having a baby born with a cleft lip and palate, a heart defect (congenital heart disease), and the risk of a premature (preterm, 'prem' or early) labour.

You can buy folic acid tablets from pharmacies. Also, the NHS Healthy Start scheme provides vitamin supplements that contain folic acid. These are free to many women who are on certain benefits - see: www.healthystart.nhs.uk.

• For most women, the dose is 400 micrograms (0.4 mg) a day.

• If you have an increased risk of having a child with a spinal cord problem then the dose is 5 mg a day. You need a prescription for this higher dose - that is, if:

• You have had a previously affected pregnancy.

• You or your partner have (or have a family with) a spinal cord defect.

• You are taking medication for epilepsy.

• You are obese - especially if your body mass index (BMI) is 30 or more.

• You have coeliac disease, diabetes, sickle cell anaemia, or thalassaemia.

Ideally, start taking folic acid tablets before becoming pregnant. The common advice is to start from the time you stop using contraception. If the pregnancy is unplanned then start taking folic acid tablets as soon as you know that you are pregnant. However, a recent study looked at the effect of taking folic acid for a year prior to becoming pregnant.

This study looked at the effect folic acid had on reducing preterm labour and delivery of the baby (that is, of having a 'prem' baby). The study found a significant decrease in the rate of preterm delivery for women who took folic acid for one year prior to becoming pregnant. So, you may wish to consider taking folic acid tablets well before you plan to become pregnant. Because of the substantial benefits of folic acid, some countries routinely fortify staple foods, such as wheat, cornflour, or rice, with folic acid. Currently there is debate as to whether the UK should follow suit and fortify certain common foods with folic acid. Many foods contain folic acid, including vegetables such as spinach, sprouts, broccoli, green beans, and potatoes. Some bread and breakfast cereals are fortified with folic acid.

However, the intake for each individual can vary.

Vitamin D supplements: vitamin D is needed for growth and supplements are recommended for all pregnant women, breast-feeding women and breast-fed babies.

The dose if you are pregnant or breast-feeding is 400 units (10 micrograms) daily. Some experts think that women who get little or no sunshine on their skin need a higher dose, such as 800 units (20 micrograms) daily. This is because most of the vitamin D that we get is made in the skin with the help of sunlight. Your doctor will advise. Pregnant women can get free prescriptions and vitamins.

Iodine: a research study published in 2011 concluded that it is likely that many young women in the UK do not get enough iodine in their diet and are lacking in iodine. Iodine mainly comes from milk, yogurt, eggs and fish. Because iodine intake can be variable, some countries routinely fortify cereals and bread with iodine - but not the UK. Iodine is essential for the brain development of a baby in the womb (uterus). The research author's concern is that many pregnant women will be lacking in iodine. This may cause their baby to have reduced brain development and be less intelligent than they would otherwise have been. Further research is needed in this area. But, in the meantime, you may wish to consider whether your diet has enough iodine. And, if it doesn't, perhaps talk to your doctor about taking an iodine supplement. A link to the NHS analysis on this study is given at the end.