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Healthy eating

While we know the old adage of ‘eating for two’ is a myth, what about weight gain in pregnancy or exercise? Here’s what you need to know.

As well as the small human you’re growing, other things will be contributing to your pregnancy weight gain. They include:

  • the placenta
  • amniotic fluid
  • extra water in the body
  • growing breasts.

(IQWiG, 2018)

"As all women are different, there is no ‘ideal’ weight gain in pregnancy. Instead, what you put on will be based on you as an individual."

BMI calculator

Your BMI (Body Mass Index) can show what weight range you’re in at the start of pregnancy.

If you divide your weight in kilograms by the square of your height in metres, you’ll get your BMI. Here’s what it means:

  • Under 18.5 = underweight
  • Between 18.5 and 25 = ‘normal’ weight
  • Between 25 and 30 = overweight
  • Over 30 = obese.

(NICE, 2010; IQWiG, 2018)

Normal weight gain in pregnancy based on BMI

Here’s what weight gain you might expect:

  • If you were underweight before pregnancy, you should put on 12.4kg to 17.9kg (1st 13lb to 2st 11lb).
  • If you were a ‘normal weight’ before pregnancy, you should put on 11.5kg to 15.8kg (1st 11lb to 2st 6lb).
  • If you were overweight before pregnancy, you should put on 7kg to 11.5kg (1st 1lb to 1st 11lb).
  • If you were obese before pregnancy, you should put on 5kg to 9kg (11lb to 20lb).

(IOM, 2009)

Putting on too much or too little weight

If you’re pregnant and overweight, you’ll have a bigger risk of:

(Sebire, 2001a; Weiss, 2004)

Being underweight can cause:

  • premature births
  • low birth weight.

(Sebire, 2001b)

Putting on a lot of weight very quickly when you’re pregnant (e.g. 1kg in a week) can also be a sign of health problems like pre-eclampsia (IQWiG, 2018). See our article about pre-eclampsia and if you notice the symptoms, call your midwife, GP or NHS 111.

Gestational diabetes: symptoms, signs and risks

Putting on a lot of weight while you’re pregnant can increase your risk of diabetes – or be a sign that you’ve developed it.

Gestational diabetes is where blood sugar levels increase in women who didn’t have diabetes before pregnancy. It increases the risk of pre-eclampsia, and can mean your baby has a high birth weight too (IQWiG, 2018).

Pregnancy weight gain: how to manage it

When you’re pregnant, you could try the following tips to eating a balanced diet:

  • Base your meals on starchy foods like potatoes, bread, rice and pasta, and pick wholegrain options where possible.
  • Eat fibre-rich foods like oats, seeds, peas, beans, grains and lentils.
  • Eat a variety of and at least five portions of fruit and veg every day, replacing fatty and calorific foods with them.
  • Eat a low-fat diet (because fat is high in calories) and don’t increase your fat and/or calorie intake.
  • Avoid fried, high-fat or high-sugar food and drinks.
  • Eat a balanced breakfast.
  • Be careful with how much food you’re putting on your plate and how often you’re snacking.
  • Do plenty of walking, cycling, swimming, aerobics (if approved by your midwife) or gardening – try building it into your day.
  • Minimise the time you spend in front of the TV* or at a laptop. (*Don’t worry, we’re not saying never.)

(NICE, 2010)

Exercise during pregnancy: what’s ok in each trimester?

It’s actually ok to keep up your normal exercise routine for as long as you feel comfortable. In fact, active women are less likely to experience problems in later pregnancy and labour (NHS, 2017b).

Just bear in mind that:

  • You might need to slow down as your pregnancy progresses or if your maternity team advises you to.
  • You should be able to hold a conversation as you exercise.
  • If you weren't active before pregnancy, don't suddenly get hardcore.
  • Avoid contact sports where your bump could get hit.
  • If you start any aerobic exercise, tell the instructor that you're pregnant.
  • Start with no more than 15 minutes of continuous exercise, three times a week and build up gradually to at least four 30-minute sessions a week.

(NHS, 2017b)

Body image during pregnancy: feeling ‘fat’ or unattractive

In pregnancy, you’ll see your breasts and stomach growing, and you might have stretch marks, acne, skin pigmentation and varicose veins (WHO, 2015). There’s no doubting that your body is going through a lot right now.

You might feel brilliant when you’re pregnant but you might not. What’s more, you might not be feeling like yourself, and this can make you think you look unattractive. You might even get down or depressed. That can be dangerous if it leads to unhealthy eating habits – whether that’s eating too much, or too little (WHO, 2015).

To have more of a positive relationship with your pregnant body, try to:

  • Remember the great things your body is doing – it’s changing so your baby can grow.
  • Keep in mind that it’s only temporary.
  • Be honest with your partner, family or friends about how you’re feeling.
  • Get out for a swim or walk to clear your mind whenever you feel down.
  • Take up prenatal yoga.
  • Practice self-massage or go for a massage if your midwife says that’s fine.
  • Learn loads about pregnancy to give you that feeling of being in control.

(Office on Women’s Health, 2016)

If you’re concerned about the way you feel, speak to your midwife or GP.

This page was last reviewed in September 2018.

Further information

Our support line offers practical and emotional support with feeding your baby and general enquiries for parents, members and volunteers: 0300 330 0700.

We also offer antenatal courses which are a great way to find out more about birth, labour and life with a new baby.

Check to see if there are any NCT Yoga for pregnancy classes in your area.

IOM (The U.S. Institute of Medicine) (2009) Weight gain during pregnancy: reexamining the guidelines. Available from: [Accessed 18th March 2018].

IQWiG (Institute for Quality and Efficiency in Health Care). (2018) Pregnancy and birth: weight gain in pregnancy. Available from: [Accessed 18th March 2018].

NHS. (2017a) Have a healthy diet in pregnancy. Available from: [Accessed 18th March 2018].

NHS. (2017b) Exercise in pregnancy. Available from: [Accessed 18th March 2018].

NHS. (2018) Pre-eclampsia. Available from: [Accessed 18th March 2018].

NICE. (2010) Weight management before, during and after pregnancy. Available from: [Accessed 18th March 2018].

Sebire NJ, Jolly M, Harris J, Regan L and Robinson S. (2001a) Is maternal underweight really a risk factor for adverse pregnancy outcome? A population‐based study in London. BJOG: an international journal of obstetrics & gynaecology. 108(1):61-66. Available from:… [Accessed 18th March 2018].

Sebire NJ, Jolly M, Harris JP, Wadsworth J, Joffe M, Beard RW, Regan L, Robinson S. (2001b) Maternal obesity and pregnancy outcome: a study of 287 213 pregnancies in London. International journal of obesity. 25(8):1175. Available from: [Accessed 18th March 2018].

Weiss JL, Malone FD, Emig D, Ball RH, Nyberg DA, Comstock CH and Carr SR. (2004). Obesity, obstetric complications and caesarean delivery rate–a population-based screening study. American Journal of Obstetrics & Gynecology. 190(4):1091-1097. Available from: [Accessed 18th March 2018].

WHO (World Health Organisation). (2015) Body image and pregnancy. Available from:  [Accessed 18th March 2018].

Office on Women’s Health. (2018) Pregnancy and body image. Available from: [Accessed 18th March 2018].

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