Harvey Group Practice

- a general practice for you -

Health Information

Planning to Become Pregnant

Planning to Become Pregnant

This leaflet offers advice if you are planning to become pregnant. The aim is to plan ahead to reduce the risk of harm to the baby and to reduce the risk of pregnancy complications. If you take any regular medication, or have a long-term medical condition, see your doctor to discuss any changes which may need to be made. Do this before you are pregnant ideally, in case anything might affect your baby.

There is a summary checklist at the end of the leaflet.

This leaflet mainly covers issues which may be relevant if you are planning to become pregnant. If you are already pregnant, you may find the separate leaflet called Diet and Lifestyle during Pregnancy more helpful.

You should take folic acid tablets (supplements) if you are thinking about becoming pregnant. Ideally, do this from at least one month before you get pregnant; continue taking them until at least the end of the 12th week of pregnancy. This is even if you are healthy and have a good diet.

Folic acid is a vitamin which occurs naturally in certain foods 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. When you are pregnant, you need a good supply of folic acid 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.

Folic acid is a naturally occurring vitamin which your body needs. By taking these supplements you are making sure that you have a good, regular amount of folic acid which you need especially during pregnancy. You can buy folic acid tablets from pharmacies. Also, the NHS Healthy Start scheme (see below) provides vitamin supplements that contain folic acid. These are free to many women who are on certain benefits.

For most women, the dose is 400 micrograms (0.4 mg) a day. If you have a higher 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:

Ideally, start taking folic acid tablets before becoming pregnant. The common advice is to start from the time you plan to become pregnant. If the pregnancy is unplanned then start taking folic acid tablets as soon as you know that you are 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.

Vitamin D is needed for growth. Vitamin D supplements are recommended for all pregnant women, breast-feeding women and breast-fed babies. If you are at risk of having a low vitamin D level, it may be worth starting to build up the level in your body before you become pregnant. The following might make you more at risk of vitamin D deficiency.

  • We obtain much of our vitamin D from sunlight, so you might be more at risk of low levels if you do not have much exposure to sunlight. For example, if you only go out covered up or if you are housebound.
  • If you are of South Asian, African, Caribbean, or Middle Eastern family origin,
  • If your diet is low in vitamin D. For example, if you eat no oily fish, eggs, meat, or vitamin D-fortified margarine or breakfast cereal.
  • If you are overweight, with a body mass index (BMI) which is more than 30.

Before becoming pregnant, consider how much alcohol you drink. It is known that alcohol can pass through the placenta and damage your developing baby but it is not known how much alcohol is safe. It is likely that it is different in different people. It is also easy to underestimate how much you drink. So most authorities advise avoiding all alcohol in pregnancy in order to be completely safe. In the first three months of pregnancy, drinking alcohol makes you more likely to have a miscarriage. In these early stages the baby is developing rapidly and alcohol can cause abnormalities. If you are planning a pregnancy, it is wise to cut down your alcohol intake and ideally to stop altogether. If you do this, you won't find you have been drinking alcohol before you realised you were pregnant.

At its worst, alcohol in pregnancy can cause a combination of abnormalities in the developing baby, called the fetal alcohol syndrome. Lesser amounts of alcohol can also cause problems in the baby such as poor growth, preterm birth and physical and mental disabilities.

The Department of Health is proposing new guidelines of safe drinking for everyone, pregnant or not. The advice is not to drink more than a maximum of 14 units of alcohol per week and to spread this out over at least three days. One unit of alcohol is in about half a pint of beer, or two thirds of a small glass of wine, or one small pub measure of spirits. See separate leaflet called Alcohol and Sensible Drinking for more details.

If you are already dependent on alcohol you should be open and honest about the amount you drink, for the sake of your baby's health. If you are planning a pregnancy, go to see your doctor before you become pregnant so that professional help can be arranged.

If you smoke, you are strongly advised to stop before getting pregnant. This is to benefit your health and the health of your future baby. Tobacco smoke contains poisonous chemicals which pass into your bloodstream when you smoke and then on into the growing baby's blood. It is advised that neither you nor your partner smoke.

Smoking when you are pregnant gives a higher risk of:

  • Having a miscarriage.
  • Having a pregnancy which does not develop in the normal place (ectopic pregnancy).
  • Slow growth of the baby leading to a low birth weight.
  • Premature labour.
  • Bleeding towards the end of pregnancy, due to the placenta coming away from the wall of the womb early. This is called placental abruption. The placenta is the tissue which supplies the nutrients the baby needs, so this may harm the baby.
  • Stillbirth.
  • Your baby having abnormalities such as a cleft lip or palate.

Even after the birth, children of smoking parents have an increased risk of:

Stopping smoking reduces all these risks. See separate leaflet called Smoking - The Facts for more details.

You and your baby will have the most benefit, and the risks will be most reduced, if you stop before you become pregnant. Planning to become pregnant is a good incentive to stop smoking for many women and is often a good time to persuade partners to give up too.

For many people it is not easy to stop. Some tips are available in the separate leaflet called Pregnancy and Smoking.

There are also medications that can help you quit.

Nicotine replacement therapy (NRT) can help if withdrawal symptoms are troublesome. Nicotine gum, sprays, patches, tablets, lozenges and inhalers are available to buy, and on prescription. Using one of these increases your chance of stopping smoking if you really want to stop. A pharmacist, GP, or practice nurse can advise about NRT. If you are not yet pregnant but are planning a pregnancy, an option is to try a course of NRT before becoming pregnant.

Medicines called bupropion and varenicline can also help. These are available on prescription. One of these may be useful before you become pregnant. These medicines roughly double your chance of stopping smoking if you really want to stop. They help to reduce the symptoms of nicotine withdrawal. But note:

  • You should not take these medicines when you are pregnant, as the risk to the unborn child is not known.
  • If you take one of these medicines, the course should be completed before you become pregnant.

GPs, practice nurses, or pharmacists can provide information, encouragement and tips on stopping smoking. Also, throughout the country there are specialist NHS Stop Smoking Clinics which have good success in helping people to stop smoking. Your doctor can refer you to one if you are keen to stop smoking. You can also call the NHS Smoking Helpline on 0300 123 1044, or visit the NHS Stop smoking website. The website link is listed at the end of this leaflet

If you take or inject recreational drugs, you are strongly advised to stop before becoming pregnant. Their effects on pregnancy are not fully known. However, there is an increasing amount of evidence to suggest that they are likely to pose a risk of damage to the baby. Examples include:

  • If you take or inject heroin when you are pregnant it may increase the risk of:
    • Miscarriage.
    • Slowing the growth of the baby, leading to a low birth weight.
    • Premature labour, leading to the baby being 'prem'.
    • Stillbirth.
    • The baby having withdrawal symptoms after the birth.
  • Using cocaine when you are pregnant is particularly hazardous. It may increase the risk of:
    • Serious life-threatening bleeding from the womb in late pregnancy (placental abruption).
    • Miscarriage.
    • Slowing the growth of the baby, leading to a low birth weight.
    • Premature labour leading to the baby being 'prem'.
    • Stillbirth.
    • Possibly, abnormalities of the baby when it is born.

However, the above are just two examples. There are many recreational drugs and it is beyond the scope of this leaflet to discuss each drug in turn. But, you can contact Frank (see below) for information about individual drugs.

If you intend to become pregnant you should aim to stop taking or using recreational drugs. It is best to postpone the pregnancy until you are off drugs. If you have an unplanned pregnancy you should aim to stop the drugs as soon as possible.

Some people can stop drugs without any help; however, many people will require help. If you cannot come off drugs easily, see your doctor for help. Your doctor will be able to refer you to a local community drug team for help. Most community drug teams can:

  • Offer treatment plans. For example, one option for people who use heroin is to take substitute therapy with methadone in place of injecting heroin. This option is safer than injecting heroin during pregnancy.
  • Provide counselling and information.
  • Provide harm-reduction activities such as needle exchange schemes.

If you are obese or overweight, try to lose some weight before becoming pregnant. Women who are overweight or obese have a greater risk of:

  • Having difficulty in conceiving.
  • Diabetes in pregnancy.
  • High blood pressure in pregnancy.
  • Blood clots (thromboembolism) in pregnancy.
  • Needing a caesarean section.
  • Premature deliveries.
  • Babies with abnormalities such as spina bifida.

The more overweight you are, the greater the risk. Being underweight is also associated with problems in becoming pregnant and complications in pregnancy. If your BMI is between 18.5 and 24.9, you have ideal body weight in preparation for pregnancy.

Eat a healthy balanced diet

Aim to eat a healthy diet (which everyone should be eating, not just pregnant women). Briefly, a third of most meals should be starch-based foods (such as bread, cereals, potatoes, rice and pasta), with fruit and vegetables. Choose wholegrain options where possible. Eat some protein foods such as meat, fish, pulses, chicken, etc, each day. 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. (Low-fat 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.

What about supplements?

As mentioned, folic acid and vitamin D supplements are recommended for all pregnant women. Otherwise, apart from possibly iodine (see below), no other supplements are routinely advised if you have a normal diet. However, some women have low iron stores which puts them at risk of becoming anaemic during pregnancy. The routine blood tests that are done during pregnancy will detect anaemia and the need for iron supplements.

Iodine - Iodine is known to be important for the healthy development of the brain of the fetus. A woman who is pregnant needs more iodine than usual to supply the developing fetus. If they do not have enough iodine, babies' learning abilities may be affected in later life. 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. Some salt contains iodine, but not all. Most people try to avoid using much salt in line with health recommendations. So there are concerns that some pregnant women may not be getting sufficient iodine in their diet. One recent study listed below suggests that all women should have iodine supplements in pregnancy. This decision has not been made for the UK; however, it may be worth considering whether your diet has enough iodine if you are planning pregnancy.

What about 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 which may be 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.

Foods and drinks to avoid

You should not eat the following if you are pregnant or trying to become 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. Listeria, a germ (bacterium), 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 or smoked 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).
  • Caffeine should be limited to no more than 300 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.

Avoid contact with sheep and lambs at lambing time. This is because some lambs are born carrying the germs that cause infections such as listeriosis, toxoplasmosis and chlamydia. These may be passed on to you and your unborn baby. Toxoplasma is also found in cat poo (faeces). Always wash your hands after handling cats and ask someone else to wash out cat litter trays.

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, some medicines are not safe and may be harmful to a developing baby - in particular, if you take them in the early weeks of pregnancy. Therefore, always tell a doctor or dentist who prescribes medication for you that you intend to become 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 you about this. Always tell a doctor or dentist who prescribes your medication that you intend to become pregnant.

If you already take regular medication, it is extremely important that you discuss this with a doctor before becoming pregnant. It may be that this medication is not safe for use in pregnancy and you will be changed to a safer alternative. In some cases you will be referred to a specialist to discuss this. Medication which may need to be changed includes:

If you are on any medication which needs changing, continue using contraception until this has happened. This is so that you do not become pregnant whilst on medication which may harm your baby. 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.

Rubella (German measles)

If you plan to become pregnant for the first time, you should check that you are immune to rubella before becoming pregnant. See your practice nurse for a pre-pregnancy blood test. Most women are immune to rubella, as they have been immunised as a child. However, childhood immunisation does not work in every child and you may not be immune. If you are not immune, you can be immunised.

Note: you should not become pregnant for one month after the injection and ideally until your immunity has been confirmed by a further blood test.

The rubella virus causes a mild illness but can seriously damage an unborn baby, especially in the early stages of growth. So, until you know that you are immune (from the result of the blood test), you should avoid anyone who has rubella, especially in the first 16 weeks of pregnancy.


Toxoplasmosis is a germ (bacterium) commonly found in raw meat and in sheep, lamb and cat poo (faeces). It can sometimes cause serious harm to an unborn baby. To avoid it:

  • Wash your hands after handling raw meat.
  • Do not eat raw or undercooked (rare) meat.
  • Wash salads and vegetables, as any dirt may have been contaminated by cat faeces.
  • Wash your hands after handling pets or animals, especially cats and kittens.
  • Get someone else to clean out any cat litter trays when you are pregnant.
  • Always wear gloves when gardening.
  • Avoid sheep, especially during the lambing season.

Food poisoning

Various germs (bacteria, viruses or similar) can cause food poisoning. Food poisoning causes tummy (abdominal) pain, runny stools (diarrhoea) and vomiting. Two germs that are of particular importance to avoid during pregnancy have already been mentioned - listeria and toxoplasma. It is possible that other food poisoning bacteria may also cause complications during pregnancy. For example, gut infection with bacteria called salmonella and campylobacter may be associated with an increased risk of pregnancy complications. So, it is wise to be extra vigilant about avoiding food poisoning.

Therefore, be strict about food hygiene:

  • Always cook eggs and meat, including poultry, thoroughly.
  • Wash fruit and vegetables.
  • Wash your hands after going to the toilet, before handling food, before eating and after handling raw meat or animals.


Having chickenpox when pregnant can be a nasty illness and there is some risk to the developing baby. A vaccine is offered to healthcare workers (doctors, nurses, etc) who have not previously had chickenpox and so are not immune and may catch chickenpox. (About 1 adult in 10 has not had chickenpox as a child.) Non-immune healthcare workers should consider having this vaccination before becoming pregnant. If you are not sure if you have had chickenpox, a blood test can check if you have previously had it.

Hepatitis B

A mother who is infected with hepatitis B has a high risk of passing it on to her newborn baby. If you are at high risk of catching hepatitis B, you should be immunised against this virus before becoming pregnant. People at increased risk and who should be immunised include:

  • Those whose job puts them at risk of contracting hepatitis B - for example, healthcare personnel and staff at daycare or residential centres.
  • Those who inject recreational (illicit) drugs.
  • Those who change sexual partners frequently.
  • Those who live in close contact with someone infected with hepatitis B.

If you think that your job may pose a risk to a pregnancy then ideally you should discuss this with your employer before becoming pregnant. Certain jobs and workplaces may pose a risk to a pregnancy, in particular to the early stages of pregnancy. For example:

  • Raw meat is sometimes contaminated with germs, such as listeria and toxoplasma. If these germs infect adults, they may cause listeriosis or toxoplasmosis, but may cause little harm. However, these germs can cause serious problems to your unborn child if you become infected when you are pregnant.
  • If you work with certain animals. For example:
    • You should avoid contact with sheep and lambs at lambing time. This is because some lambs are born contaminated with germs such as listeria, toxoplasma and chlamydia which may affect you and your unborn baby.
    • Cats and kittens often carry toxoplasma germs - especially in cat poo (faeces). So, cleaning out cat litter trays and handling cats and kittens can be a risk.
  • If your job puts you at risk of contracting hepatitis B, you should be immunised against this virus. For example, if you are a healthcare worker, or work at a daycare or residential centre. (Women with hepatitis B can pass on the infection to their child at childbirth.)
  • If you work with chemicals, fumes, radiation, etc. Some may be toxic to an unborn baby.

The above are just examples. In short, if you think that your occupation may pose a risk to a pregnancy, then you should discuss this with your employer before becoming pregnant. A change in job, or working practice, may be necessary.

You and your employer may wish to download information guides from the Health and Safety Executive (HSE) website (see below). They have an Information line if you have a health and safety concern at work but do not wish to discuss with your employer your intention to become pregnant.

Women with certain medical conditions may benefit from advice before becoming pregnant. If you have any of the conditions listed below, it would be sensible to continue using contraception until you have discussed with your doctor that you are considering becoming pregnant. If you have an unplanned pregnancy and have any of these conditions, see your doctor as soon as possible. Do not stop any medication without talking to your doctor.


If you have diabetes, it is extremely important to see your doctor BEFORE you become pregnant. This is because good control of your sugar levels, both before pregnancy and in early pregnancy, can reduce various risks. Diabetes increases your risk of miscarriage and stillbirth. It also increases the risk that your baby will be born with abnormalities, or become seriously ill after birth. However, good control of sugar levels starting before pregnancy can reduce these risks. You will be referred to a specialist in diabetes, and your medication (and/or insulin) may be changed. You will have checks on your eyes and your kidneys. You will work with your specialist together to get your blood glucose levels within a very tight range. The better the control before pregnancy and during early pregnancy, the better the outcome. This is why you should plan ahead and see your GP or specialist before you get pregnant.


Many treatments for epilepsy are not safe to take in pregnancy. See your doctor or epilepsy specialist to discuss this BEFORE becoming pregnant. You may need to be switched to another medication. However, it is risky to have fits in pregnancy too, so do not stop your medication suddenly without discussing it with your specialist. It is advisable to keep taking contraception until you have had this discussion.

High blood pressure (hypertension)

If you are on medication for high blood pressure, ideally see your GP before becoming pregnant. As discussed in the medication section above, there are some blood pressure tablets which should not be taken if you are pregnant. Your doctor will advise if you need to change and may refer you to a specialist for further advice.

Mental health

If you are taking medication for depression, anxiety, bipolar disorder or schizophrenia, see your doctor to discuss this before becoming pregnant. You and your GP or mental health specialist will need to weigh up the risks of taking medication in pregnancy against the risks of becoming mentally ill if you stop. It may be that your medication will be changed to be safer in pregnancy. Unfortunately, there is not much information available on how safe most medication is in pregnancy. Your doctor will explain what is known about your medication, and together you can make a decision about whether you need to stop or change.

If you have a past history of severe mental health illness, it is best to be under the care of a specialist who can monitor you during pregnancy. You should have access to details about whom to contact if you feel you are becoming unwell.

Hereditary conditions

If your family has a history of a condition that runs in families, you may wish to have genetic testing before planning a pregnancy. This will help work out your chances of having that condition. Examples of conditions which may run in families include:

  • Huntington's disease.
  • Neurofibromatosis.
  • Tuberous sclerosis.
  • Marfan's syndrome.
  • Adult polycystic disease.
  • Achondroplasia.
  • Cystic fibrosis.
  • Tay-Sachs disease.
  • Gaucher's disease.
  • Friedreich's ataxia.
  • Congenital adrenal hyperplasia.
  • Spinal muscular atrophy.
  • Duchenne muscular dystrophy.
  • Fragile X syndrome.
  • Haemophilias A and B.
  • Glucose-6-phosphate dehydrogenase deficiency.

Other medical conditions

Other conditions for which it is best to see a doctor before becoming pregnant include:

Screening tests

Pregnant women in England, Scotland and Wales and those at high risk in Northern Ireland are offered a screening test for sickle cell disease and thalassaemia. Some women may wish to have the screening test before becoming pregnant, especially if their family origins make these diseases more likely. If you or your partner or either of your families originate from Southeast Asia, Sardinia, Greece, Turkey or Cyprus, it may be worth having a screening test before pregnancy. See your doctor to discuss this. Genetic testing is a rapidly developing area of medicine. It may be possible that more tests will become available to detect carriers of various diseases. When they become available, these may be tests to consider before becoming pregnant.

All women from the age of 25 (20 in Scotland) should have a three-yearly cervical smear to check for early pre-cancer changes to the neck of the womb (cervix). This cannot be done in pregnancy or for three months after a baby is born. So, if you are thinking of becoming pregnant, check with your doctor or nurse to see if your smear is due. If it is due, have it before becoming pregnant.

Most pregnancies go well and without any major problems. But, it is wise to reduce any risks as much as possible. So, a reminder of things to consider before becoming pregnant, and as soon as you realise you are pregnant:

Things you should do

  • See your doctor to discuss pregnancy if you have any long-standing medical condition or take any regular medication. Even if you do not, it may be worth visiting your doctor or practice nurse to check your cervical smear is up to date and to have a blood test to check to see if you are immune to rubella (German measles). Your doctor or nurse will advise if any other tests are needed.
  • If you have diabetes or are on medication for epilepsy see a doctor sooner rather than later; continue contraception until any plans to control your medical condition are in place.
  • Take folic acid tablets before you become pregnant and until 12 weeks of pregnancy.
  • Take vitamin D supplements when you become pregnant.
  • Eat a healthy diet. Include foods rich in iron, calcium and folic acid; also, some oily fish.
  • Have strict food hygiene. In particular, wash your hands after handling raw meat, or handling cats and kittens, and before you prepare food.
  • Wear gloves when you are gardening.

Things you should avoid

  • Too much vitamin A - don't eat liver or liver products, or take vitamin A supplements.
  • Listeriosis - don't eat undercooked meat or eggs, soft cheese, pâté, shellfish, raw fish, or unpasteurised milk.
  • Fish which may contain a lot of mercury - shark, marlin, swordfish, or excess tuna.
  • Sheep, lambs, cat poo (faeces), cat litter and raw meat, all of which may carry certain infections.

Things you should stop or cut down on

  • Caffeine in tea, coffee, cola, etc - have no more than 300 mg per day. For example, this is about three mugs of instant coffee, or two mugs of brewed coffee, or four mugs of tea.
  • Alcohol - you are strongly advised not to drink at all.
  • Smoking - you are strongly advised to stop completely.
  • Street (illicit) drugs - you are strongly advised to stop completely.

Other things to consider

  • Your iodine intake and perhaps discuss with your doctor about iodine supplements.
  • Immunisation against hepatitis B if you are at increased risk of getting this infection.
  • Immunisation against chickenpox if you are a healthcare worker and have not previously had chickenpox and so are not immune.
  • Your medication - including herbal and 'over-the-counter' medicines. Are they safe?
  • Your work environment - is it safe?
  • Medical conditions in yourself, or conditions which run in your family.
  • Screening tests for sickle cell disease and thalassaemia.

Further help & information


23-28 Penn Street, London, N1 5DL


Tel: 0300 123 6600

HSE - Health and Safety Executive

Redgrave Court, Merton Road, Bootle, Merseyside, L20 7HS

Tel: Infoline: 0300 003 1747


165 Beaufort Park , London, NW11 6DA

Tel: (Helpline) 020 8458 5951

NCT - National Childbirth Trust

30 Euston Square, London, NW1 2FB

Tel: (Helplines) 0300 3300 770

Further reading & references

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but makes no warranty as to its accuracy. Consult a doctor or other healthcare professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Dr Tim Kenny
Current Version:
Dr Mary Harding
Peer Reviewer:
Dr John Cox
Document ID:
4240 (v47)
Last Checked:
Next Review: