Your weight gain will include your placenta, your womb and the amniotic fluid as well as your growing baby. Some fat will also be stored for making milk when your baby is born.
Every pregnant woman gains weight differently, so you will probably not be weighed at each antenatal visit. However, your doctor or midwife might want to keep a closer eye on your weight gain if they think this will help to reduce the risks to you or your baby.
Doctors find it hard to say how much women should gain in pregnancy in general because everyone is different. Some women may even lose weight during the first few months, especially if they have morning sickness. Women should not try to diet at this time or any time in pregnancy but weight loss might happen from sickness.
Most women put on between 10kg (22lb) and 12.5kg (28lb) during their pregnancy.
Your healthy pregnancy weight gain may depend on the weight you were before you became pregnant. There are no official guidelines in the UK but in the US, guidelines suggest that
- women who are underweight (BMI under 18.5) should put on between 28-40 lbs (13-18kg)
- women in the normal weight range (BMI of 18.5-24.9) should put on between 25-35lbs (11-16kg)
- women who are overweight (BMI between 25 and 29.9) should put on between 15-25lbs (7-11kg)
- women who are obese (BMI of 30 or more), should put on between 11-20 lbs (5-9kg).
Dieting during pregnancy is not recommended as it may harm your unborn baby. But if you are obese and make healthy changes to your diet you might not gain any weight in pregnancy, and you might even lose a small amount. The Royal College of Obstetricians and Gynaecologists says that this is not harmful.
The most important thing is to keep your weight gain to a safe and healthy level for you and your baby. Talk to your doctor or midwife if you're worried about how much weight you should be putting on and they will be able to advise and reassure you about what is right for you. If you are underweight or overweight, you are likely to get extra care and support during your pregnancy.
How can I manage how much weight I put on during my pregnancy?
Pregnancy is not the time to make lots of sudden big changes but neither is it a time to sit back and 'eat for two'.
Staying active is safe and healthy for you and your baby, and you do not need extra calories until the third trimester (at which point you only need an extra 200 calories).
Instead of starting a tough exercise regime you can incorporate more activity into your normal life. There are lots of ideas in this section and in our section about being active in pregnancy.
You can also find out about healthy eating and get some great tips for easy meals and snacks in our section about eating well in pregnancy.
Most types of exercise are fine even if you are overweight. Being active during your pregnancy is safe and healthy for you and your baby.
Your questions about how being an unhealthy effects your pregnancy.
It's important to look after yourself and start managing your weight as early as possible in your pregnancy to get the most benefit. Having some goals and planning what you're going to do will help.
Most women who get pregnant after weight-loss surgery have an uncomplicated pregnancy and birth. The risks to you and your baby are lower after surgery than if you kept a very high body mass index (BMI).
There is plenty of support available to help you manage your weight during your pregnancy and after your baby is born.
Keeping active is great for you and your baby.
- Institute of Medicine (2009) Weight Gain During Pregnancy: Re-examining the Guidelines
- NICE (2010) Dietary interventions and physical activity interventions for weight management before, during and after pregnancy, Public health guidance 27, 2010
- RCOG (2011) Why your weight matters during pregnancy and after birth
ℹLast reviewed on April 1st, 2014. Next review date April 1st, 2017.