Improving your diet and working towards a healthy weight if your body mass index (BMI) is too high or too low are two things you can do now to improve your chances of having a healthy pregnancy and baby.
Any changes you make, no matter how small, are a step in the right direction and you may be surprised at what you can do.
Getting to a healthy weight before you get pregnant gives you the best chance of a healthy pregnancy.
Regular physical activity can help you reach and stay at a healthy weight.
What is a healthy weight?
Your BMI (Body Mass Index) is a measure that uses your height and weight to work out if your weight is in a healthy range. A healthy BMI is between 18.5 and 24.9.
If you have a high BMI
Being overweight can affect your self-esteem and this can make it harder to ask for help. Being physically active and having a healthy diet with healthy portion sizes will help you bring your weight down closer to the healthy range BMI. Speak to your GP if you’re struggling to lose weight. They can give you information about how to lose weight safely.
Some medicines that treat schizophrenia, bipolar disorder and severe depression (antipsychotics) can cause weight gain.
This is because they can make you feel hungrier so you eat more. They can also make you feel tired, so you’re less likely to keep active.
If you’re taking these medicines, it’s even more important to make the extra effort to follow a healthy diet and keep physically active to help prevent or reduce weight gain.
If your weight gain is caused by your mental illness medication, you may be able to change to a different medicine. It’s important not to stop taking your medication without speaking to your doctor first.
A high BMI means you are at higher risk of certain pregnancy conditions, such as pre-eclampsia and gestational diabetes. It also puts your baby’s future health at risk as obesity can pass down the generations. Dieting is not advised during pregnancy so now is a good time to reach a healthy BMI.
Your partner’s weight is also important. Male obesity can affect the quality and number of sperm and the future health of the baby.
If you have a low BMI
If your diet is causing your low weight, you could try following these 3 tips for healthy eating below.
- Aim to gain weight slowly.
- Try not to use sugary or high fat foods such as chocolate, cakes and sugary drinks.
- Have regular meals with healthy snacks that are high in unsaturated fats, such as nuts.
If you have an eating disorder, you may find it difficult to get all of the nutrition you need during pregnancy. Some women feel sensitive about changes to their body shape during pregnancy but this can get easier in the later stages of pregnancy. If you binge eat, you may struggle with feeling hungrier than usual in the last trimester.
You could try:
- making a list of reasons why you want to eat well during your pregnancy
- eating small meals more often during the day
- making sure you always have healthy snacks with you.
Purging by vomiting or using laxatives can affect you and your baby. If you feel like purging, you could try distracting yourself by going for a walk or doing something you find calming.
Your GP or midwife can offer you support. Treatment may include talking therapies, which aim to help you gain control over your eating disorder so you can work towards reaching a healthy weight.
There’s more information on the Eating disorders and pregnancy website.
How can my diet affect my fertility and pregnancy?
Eating a healthy diet may improve your chances of getting pregnant. Your partner’s diet may also be important because eating healthily can improve sperm quality. We don’t fully understand how diet affects fertility but we do know that eating a healthy diet before you get pregnant improves the chances of becoming pregnant sooner.
Too much caffeine can harm a baby in the womb and increases the risk of miscarriage. Caffeine is found in coffee, tea, some soft drinks, energy drinks and chocolate. If possible, avoid caffeine if you’re trying to get pregnant or you are pregnant. Otherwise, have less than 200mg a day – this is the same as 2 mugs of instant coffee or 5 cans of cola.
What is a healthy diet?
Healthy eating for pregnancy is the same as at any other time in your life. There’s no need to eat more than usual during the first 2 trimesters of pregnancy.
Any changes you can make to improve your diet will help you have a healthy pregnancy. It doesn’t have to cost a lot. You can get ideas for low cost meals from Jack Monroe’s website, Cooking on a bootstrap.
Here are some tips for eating a healthy diet:
- Aim for at least 5 portions of different fruits and vegetables each day (3 vegetable if possible).
- Choose wholegrain or higher fibre varieties of starchy food, such as bread, rice and pasta. Leave the skin on potatoes.
- Choose lower fat and lower sugar versions of dairy products, such as milk, cheese and yoghurt.
- Eat some beans, pulses, fish, eggs and lean meat.
- Cut down on red and processed meat, such as sausages, bacon and ham.
- Try to eat two portions of fish a week, with one being an oily fish, such as sardines.
- You only need a small amount of fat – unsaturated fats, such as sunflower oil and nuts, are healthier than saturated fats like butter and ghee.
- Avoid sugary food and drink, such as sweets, biscuits, cakes and fizzy drinks.
The Eatwell Guide shows you how much of each food type to include in your diet.
Should I take supplements?
All women should start taking 400 mcg folic acid daily before getting pregnant. This is to help prevent problems with the baby’s development in the womb, such as spina bifida. If you’re already pregnant, start taking folic acid straight away and continue until you are 12 weeks pregnant.
You may need to take a higher dose of folic acid if you are very overweight (BMI over 30), have diabetes, sickle-cell disease or epilepsy, or if you have a family history of neural tube defects. Your GP or pharmacist can get you a free prescription.
Most women don’t need to take any other supplements but you may want to think about taking a vitamin D supplement between September and March. Your GP or pharmacist can help you make sure you’re getting all the nutrients you need.
Don’t take any supplements containing vitamin A, such as liver or fish oil as high doses can affect the development of the baby in the womb.
If you’re pregnant and aged under 18 or on benefits, you may be able to get vouchers for healthy food and vitamins from the Healthy Start scheme. If you don’t qualify, ask your midwife if there is any local help towards the cost of vitamins.
How can my diet and activity affect my mood?
Improving your diet and being more active won't 'fix' your mental illness, but it can help with your day to day wellbeing. There is research to show that it can:
- improve your mood
- give you more energy.
Even eating certain types of food can affect our mood. For example, if your body isn’t getting enough vitamins and minerals from your food, it can affect your mood, energy levels and brain function.
Some women use food to help them cope with problems in their daily lives. You may ‘comfort eat’ or eat fatty foods to help you feel better. Or you may feel more in control when you don’t eat or if you purge. These may help in the short term, but in the longer term they can cause health problems that can make pregnancy higher risk.
More information and support
Eating disorders and pregnancy
Information on nutrition for women with an eating disorder
Information on what to include in a healthy, balanced diet.
Free food and vitamin vouchers for women under 18 or on benefits.