Your BMI (body mass index) is routinely calculated at the start of your pregnancy. This is a measure of your weight in relation to your height. Your healthcare team can work it out for you. Whilst it does not indicate how healthy you are, being overweight (BMI above 30 kg/m2) is correlated with a higher chance of complications in pregnancy(see the RCOG patient information Being overweight in pregnancy and after birth.

Your healthcare team will support you to keep well in pregnancy whatever your BMI. They will discuss any concerns they have with you and ensure that you are able to make informed choices about your pregnancy and birth

Trying to lose weight by dieting during pregnancy is not recommended as it may harm the health of your baby. If you are concerned about your weight, your midwife can advise you and may refer you to a dietician.

In general, eating fish is a healthy option during pregnancy, but the current advice from the Department of Health is to eat no more than two portions of oily fish, such as mackerel or salmon, a week. This is because too much of a substance found in oily fish (mercury) can be harmful to your baby’s development.

Also, pregnant women should not eat more than two fresh tuna steaks or four medium-sized cans of tuna a week, and should avoid eating shark, swordfish or marlin.

Liver can contain high levels of vitamin A, which in high doses can harm the development of your baby’s nervous system. It is rare for women in developed countries like the UK to be deficient in vitamin A so you should avoid eating foods such as liver and liver products like pâté.

You can eat peanuts or foods containing peanuts (such as peanut butter) while pregnant or breastfeeding. Eating peanuts does not appear to affect your baby’s chances of developing a peanut allergy. Avoid eating them if you are allergic to them.

You can pick up some infections, such as listeria, salmonella or toxoplasmosis, from contaminated food. These can harm your baby if you catch these infections while you are pregnant.

To reduce your risk of getting listeriosis:

• drink only pasteurised or UHT milk
• avoid eating ripened soft cheese such as Camembert, Brie or blue-veined cheese; however, hard cheese varieties such as Cheddar, cottage cheese and processed cheese are safe
• avoid eating pâté
• avoid eating undercooked food; make sure that ready-prepared meals are cooked as per instructions, paying particular attention to making sure that they are piping hot when reheating.

To reduce your risk of getting salmonella:

• Avoid eating raw or partially cooked eggs that have not been produced under the British Lion code (for example in mayonnaise, soufflé or mousse). It is safe to eat these eggs once they are cooked until the white and the yolk are hard.
• Eggs produced under the British Lion Code of Practice are safe for pregnant women to eat raw or partially cooked, because they come from hens that have been vaccinated against salmonella. These eggs will have a red lion stamp on their shell and are safe to eat raw or partially cooked (eg. As soft boiled eggs).
• Avoid eating raw or partially cooked meat, especially poultry and shellfish.

To reduce your risk of getting toxoplasmosis:

• always wash your hands before and after handling food
• wash all fruit and vegetables, including ready-prepared salads
• cook raw meats and ready-prepared chilled meats thoroughly
• wear gloves and wash your hands thoroughly after gardening or handling soil
• avoid contact with cat faeces (in cat litter or in soil) – or, if you must handle it, wear rubber gloves.

Vitamins are needed for growth and development. There are 13 important vitamins: vitamins A, C, D, E and K and the vitamin B series. Apart from vitamin D, which we get from sunlight, most vitamins come from our diet. In the UK, it is quite common for people to be low in vitamin D and folic acid (vitamin B9).

These vitamins are important in pregnancy and you can boost your levels by taking a vitamin supplement. Supplements of other vitamins are not usually routinely advised and Vitamin A may actually be harmful in pregnancy. The various vitamins and whether they are recommended in pregnancy are detailed below.

Vitamins that are recommended

Folic acid

Folic acid is one of the B vitamins and helps to reduce the risk of your baby having a neural tube defect, such as spina bifida.

Taking extra folic acid may also reduce the risk of heart or limb defects and some childhood brain tumours. The recommended daily dose is 400 micrograms (µg).

Ideally, you should start taking extra folic acid before you become pregnant and continue to take it until you reach your 13th week of pregnancy. If you did not take folic acid before you became pregnant, start taking it as soon as you realise you are expecting a baby.

As well as taking a supplement, it is recommended that you eat foods rich in folic acid (for example, fortified breakfast cereals and yeast extract) and to consume foods and drinks rich in folate (for example, peas and beans and orange juice).

Some women take a higher dose of folic acid. Why?

If your risk of having a baby with a neural tube defect such as spina bifida is higher than average, you will be advised to take a daily dose of 5 milligrams (mg) of folic acid. This is higher than usual and it will need to be prescribed by a doctor. You may be advised to take an increased dose if:

• you have had a previous pregnancy affected by a neural tube defect
• you or your partner have a neural tube defect
• you have epilepsy
• you have coeliac disease
• you have diabetes
• your BMI is 30 or more
• you have sickle-cell anaemia or thalassaemia; the higher dose of folic acid will also help to prevent and treat anaemia and it is recommended that you take this throughout your pregnancy.

Vitamin D

All pregnant women are advised to take a daily dose of 10 micrograms (µg) of vitamin D when

pregnant and breastfeeding. This is because it is common in the UK for people to have low levels of vitamin D. Taking supplements can improve your baby’s growth during their first year of life, and can reduce their risk of developing rickets.

You are at particular risk of having low levels of vitamin D if:

• your family origin is South Asian, African, Caribbean or Middle Eastern
• your BMI is 30 or more
• you stay indoors a lot
• you usually cover your skin when you go outdoors or usually use sun-protection cream
• your diet is low in vitamin D-rich foods such as eggs, meat, vitamin D-fortified margarine or breakfast cereal.

If you are in one of these situations, you may be may be advised to take a higher daily dose of vitamin D.

When may I need extra vitamin K?

Vitamin K is needed for our blood to clot properly. Newborn babies have low levels of vitamin K, which puts them at risk of bleeding. To prevent this, you will be offered vitamin K for your baby after birth.

You do not need to take vitamin K supplements yourself during pregnancy unless it is thought that your baby is at particular risk of bleeding. This could be because you are taking certain medicines for epilepsy or if you have liver disease.

When may I need extra vitamin C?

Although routine supplements of vitamin C are not specifically recommended when you are pregnant, this vitamin helps iron to be absorbed. This may be of benefit because while you are pregnant you are at risk of becoming anaemic.

Vitamins that are not recommended

There are many multivitamin tablets for use in pregnancy that contain a small amount of lots of vitamins. These are safe to take, but avoid taking large doses of the following vitamins unless a doctor prescribes them for a particular reason.

Vitamin A

Too much vitamin A can harm the development of your baby’s nervous system. During

pregnancy, avoid any supplements that contain more than 700 micrograms (µg) of vitamin A and don’t eat foods such as liver, liver products (pâté) or fish liver oils that may contain this vitamin in high levels.

Vitamin E

There is currently no evidence to recommend additional vitamin E during pregnancy.

Vitamin B supplements (other than folic acid)

You do not need any other vitamin B supplements in pregnancy.

Most women do not need to take extra iron during pregnancy. Taking routine iron supplements will not necessarily benefit your health and may cause you unpleasant side effects such as heartburn, constipation or diarrhoea.

Your midwife will check your blood at your booking appointment and at 28 weeks of pregnancy. You will only be advised to take iron if you are found to be anaemic or are at increased risk of becoming anaemic in pregnancy, for example if you are having twins.

If you are on certain benefits and/or are under the age of 18 years, help may be available to provide you with free supplements. Find out more about the Healthy Start Scheme.

You can buy folic acid or pregnancy multivitamins from any pharmacy or supermarket. There is no evidence that expensive brands are any better than cheaper ones.

The following website can give you information about healthy eating before and during pregnancy and while breastfeeding:

NHS – "Have a healthy diet in pregnancy"

https://www.nhs.uk/pregnancy/keeping-well/have-a-healthy-diet/