How much weight should I gain in pregnancy?

If you have a healthy diet and stay active during pregnancy your weight gain should stay at a safe and healthy level for you and your baby. If you are unsure you midwife will be able to advise on what is right for you. You do not need to eat more food for most of the pregnancy. Your baby will take what they need. In the third trimester you will need around 200 extra calories a day.  

This film shows what that might look like

What is the average weight gain in pregnancy?

Most people put on between 22lb (10kg) and 28lb (12.5kg). That’s mostly in the second half of their pregnancy.

Your healthy weight gain during pregnancy may depend on your BMI before you got pregnant. BMI stands for body mass index. This is a measure that uses your height and weight to work out if your weight is in a healthy range.  

BMI weight ranges

The BMI weight healthy range is different for different ethnicities.  

People with a South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean family background have a higher risk of developing some long-term conditions, such as type 2 diabetes, with a lower BMI.  

If you are in these groups a BMI:

• below 18.5 is underweight
• between 18.5 and 23 is healthy  
• over 23 means increased risk (overweight)
• over 27.5 means high risk (obese).

For people of White heritage, a BMI:

• below 18.5 is underweight
• between 18.5 and 24.9 is healthy
• between 25 and 29.9 is overweight
• of 30 or over is obese.

Why does the BMI calculation change for different ethnic groups?

The BMI definition of obesity (a BMI of 30+) was originally developed using data mostly from White populations. Since then, research has found that people from a South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean family background, have a higher risk of developing some long-term conditions, such as type 2 diabetes, when they have a lower BMI.

As a result, the NHS has developed guidelines to make sure that people from these ethnic backgrounds get help to prevent developing type 2 diabetes earlier than people from White backgrounds.

There is not enough evidence yet to say whether people from different ethnic backgrounds should have different pregnancy care based on their weight.

This means that the advice and care you will have about your weight in pregnancy is the same for all women and birthing people, whatever your ethnic background.

Work out your BMI with our calculator.

Try not to get too concerned about your BMI. Your doctor or midwife will be able to advise you about what is right for you.  

Will I be weighed during pregnancy?

Your midwife will ask to weigh you at your first antenatal appointment (known as the booking appointment) so they can calculate your BMI. This is because being overweight or underweight can increase the risk of pregnancy complications.  

If your BMI is not in the healthy range, you will get extra care and support during your pregnancy and you may need to be weighed more often.

Find out more about being overweight in pregnancy.

Find out more about being underweight in pregnancy.  

This may be hard to deal with if you have always worries about your weight. But your healthcare professionals will not judge you. Their aim is to give you and your baby the best care they can.

How can I make sure my weight gain is healthy during my pregnancy?

The best thing you can do is stay active and eat a healthy, balanced diet.

Remember that exercise does not need to happen in a gym or in an organised class to be beneficial. The key is to move more and stay active. Sitting down a lot is harmful. 

Find out more about exercising in pregnancy.

You do not need to eat for 2 or to drink full-fat milk (2 common pregnancy myths). You do not need extra calories either until the third trimester (when you only need an extra 200 calories per day).

You can find out more about healthy eating, and get some great tips for easy meals and snacks, in our section about eating well in pregnancy.  

The key is to make small changes gradually to improve your diet and the amount of activity you do. There are some tips to help you set goals, here.

Do not forget to ask your midwife or doctor for support if you need it. They want to help you and will not judge you.  

Can I try to diet during pregnancy?

You may even lose weight during the first few months, especially if you have morning sickness, which is normal.  

Do not diet or try to lose weight while you're pregnant. You may not take in enough nutrients which is not healthy for you or your baby.