Questions about weight in pregnancy
Here we’ll answer some of the common questions about your weight in pregnancy, how much you should be eating and why this is important.
Why is my weight important to my pregnancy?
Being outside the ‘healthy weight’ range of the BMI scale before you get pregnant can increase the risk of pregnancy problems for you and your baby.
For example, having a BMI over 30 can increase the risk of complications, such as:
Being underweight can increase the risk of complications such as:
- miscarriage
- premature birth
- having an underweight baby.
This can be difficult to read but try not to worry. If you have an overweight or underweight BMI your midwife and doctor will give you extra care throughout your pregnancy. There are also lots of things you can do to minimise the risks, such as staying active and eating well.
How much extra should I eat in pregnancy?
You don’t need to eat any extra food during the first 6 months of pregnancy. After that, you only need an extra 200 calories a day. This is about half a sandwich. Find out more about fun and healthy 200 calorie snacks.
The most important thing is to make sure you eat a healthy, balanced diet, which will help make sure you and your baby have all the nutrients you need.
There’s no need to eat for two or drink full-fat milk. Try not to let well-meaning family and friends persuade you to have any extra helpings and try to keep foods that are high in sugar or fat, such as sweets, crisps and biscuits, as occasional treats.
Everyone is different. Find out what you can do if you are underweight and need to gain weight.
What exactly is a 'portion'?
It's not just what you eat that's important, it's how much you have of it. A portion is the amount of any one type of food you eat. For example, a fruit portion would be one apple or two plums. A vegetable portion would be a small side salad. Three heaped tablespoonfuls of cooked vegetables also count as a portion. Find out more about portion size.
Is it safe to diet during pregnancy?
Don't try to lose weight while you're pregnant as this is not healthy for you or your baby.[6] You and your baby may miss out on nutrients that you need to stay healthy and strong.
If you are concerned about putting on weight, remember that you will lose a lot of it with the birth of your baby and the placenta. And, if you have a healthy diet in pregnancy this may make it easier to lose weight after you have the baby.
Try not to worry about putting on weight. Instead, focus on being as healthy as you possibly can and aim to have a balance of different foods from the Eatwell plate. This will help keep you healthy and prevent too much weight gain.
Talk to your doctor or midwife if you have an obese BMI. You should be referred to a dietitian or ask what weight-management programmes are available for pregnant women in your area.
It's also important to stay active during your pregnancy. This will boost your and your baby’s health, as well as helping with managing your weight.
NICE Guidelines (2010) Weight management before, during and after pregnancy National Institute for Health and Care Excellence https://www.nice.org.uk/guidance/ph27
Royal College of Obstetricians and Gynaecologists Why your weight matters during pregnancy and after birth (Page last reviewed: Nov 2011) www.rcog.org.uk/globalassets/documents/patients/patient-information-leaflets/pregnancy/pi-why-your-weight-matters-during-pregnancy-and-after-birth.pdf
Clinical Knowledge Summaries (Aug 2017) Pre-conception advice and management https://cks.nice.org.uk/pre-conception-advice-and-management
Review dates
Last reviewed: 25 October, 2018
Last review: 25 October, 2021
Read more about weight management in pregnancy
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Overweight and pregnant
If you are classed as overweight or obese in pregnancy based on your BMI, it's important to manage your weight as best you can. -
Weight management in pregnancy
Although you will be putting on weight in pregnancy as your baby grows, limiting the amount of extra weight gain in pregnancy will improve your health and your baby's, both now and in the future. -
Pregnant after weight-loss surgery
Most women who get pregnant after weight-loss surgery have an uncomplicated pregnancy and birth.
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4 tips for managing your weight in pregnancy
There is plenty of support available to help you manage your weight during your pregnancy and after your baby is born. -
Staying active in pregnancy
Keeping active in pregnancy is great for you and your baby. -
Healthy eating tips
Eating a healthy, balanced diet can help you have a healthier pregnancy and manage your weight gain. -
Underweight during pregnancy
If your BMI is classed as underweight, you should get advice on how to increase and vary your diet in pregnancy. -
How much weight should I gain in pregnancy?
Everyone is different, but the amount of weight you should may depend on how much you weighed before you became pregnant.