Pregnancy Weight Gain: What’s Average?

During pregnancy, it’s perfectly normal and healthy to put on a few extra kilos. We can’t tell you exactly how much weight you need to gain – this depends on factors like your starting weight and whether you’re having a single baby or multiples.

We can, however, tell you how to achieve healthy weight gain during pregnancy, what makes up those extra pounds you’re gaining, and how many extra calories you may need now that you’re pregnant. Scroll down to find out more.

How Much Weight Should You Gain During Pregnancy?

No two mums-to-be are the same, which is why your recommended weight gain during pregnancy will mostly depend on whether you had a normal weight, or were underweight or overweight, before you became pregnant. This is determined by your pre-pregnancy BMI.

The general rule of thumb is that if you have a low BMI, then your recommended weight gain will be more than for someone with a higher BMI. If you’re uncertain about what’s right for you, talk to your doctor or midwife about the healthy amount of weight for you to gain during your pregnancy.

What Is BMI?

BMI is short for body mass index, which is a ratio derived by calculating your weight (in kilograms) divided by your height (in metres), squared. It offers an estimate for measuring body fat.

Search online for a BMI calculator or chart help you find your pre-pregnancy result and use it – along with the chart below – to find out what’s a healthy average pregnancy weight gain for someone of your build and height.

What if You’re Pregnant With Twins?

If you’re pregnant with twins or triplets, you might gain a bit more weight than a mum-to-be who’s carrying a single baby. This is perfectly normal.

You don’t need to eat much more though. In fact, the advice from experts is more or less the same whether you’re pregnant with one or more babies. That is, avoid sugary drinks and snacks and stick to a healthy diet that includes

  • plenty of fruit, vegetables and whole grains

  • some high-protein foods like lean red meat, nuts, seeds and (well-cooked) eggs

  • dairy foods like milk, cheese and yoghurt (or dairy substitutes).

If you’re pregnant with multiples, you might have a slightly higher risk of anaemia (iron deficiency), so your doctor may offer you iron supplements. You can also try and boost your iron intake by eating more foods that are rich in this mineral, such as lean red meat, leafy green vegetables, beans and iron-fortified breakfast cereals.

Staying active with gentle exercise is also beneficial – in more ways than one. For example, besides helping to keep your weight gain under control (by using up any unneeded calories), it also tones the muscles and helps prevent aches and pains caused by the extra kilos you put on during pregnancy.

Activities that are easy on the joints are best, like swimming or prenatal yoga.

What Is Considered Normal Pregnancy Weight Gain?

To get an idea of what’s considered to be normal weight gain during pregnancy, first work out your starting BMI (or use an online calculator) and check it against the table below to find your approximate recommended weight gain during pregnancy.

Recommended Weight Gain Depending on Your BMI Before Pregnancy
BMIUnderweight or Overweight?Recommended Weight Gain During Pregnancy
Below 18.5Underweight12.5-18 kg
18.5 to 24.9Normal11.5-16 kg
25 to 29.9Overweight7-11.5 kg
30 or aboveObese5-9 kg

If your weight isn’t in the normal range, don’t panic: Your midwife can advise you on how to maintain a healthy diet.

Most mums-to-be who are above the average weight range for their BMI, will give birth to a healthy baby. However, being overweight can increase the risk of complications during your pregnancy, including gestational diabetes or the rare but serious blood pressure condition preeclampsia.

Dieting to lose weight during pregnancy is not safe for your foetus, but you may be able to lower the risks by switching to a healthier diet or taking steps not to gain any more weight than necessary.

Attending all your antenatal appointments is a good way of ensuring that any problems are spotted and dealt with in good time, as your weight will be monitored at these visits.

If you have a BMI of more than 30, your midwife may recommend a different schedule of antenatal care, with extra tests and monitoring to manage the higher risks.

Related pregnancy tool

Pregnancy Weight Gain Calculator

Follow the expected weight gain during your pregnancy week by week.

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Where Does the Extra Weight in Pregnancy Come From?

Typically, only a small portion of the weight you gain during pregnancy is actually fat. The average weight gained during pregnancy is 10 to 12.5 kg. Here is a breakdown of what that’s made up of:

  • Your baby (around 3-3.5 kg)

  • Uterus (around 1kg)

  • Amniotic fluid (around 1kg)

  • Placenta (around 700 g)

  • Larger breasts (around 2kg)

  • Increased blood and fluid volume (up to 2kg)

  • Extra fat stores (around 3kg).

Why Do You Gain Weight During Pregnancy?

Much of the extra weight you normally gain during pregnancy is to provide your growing foetus with the nourishment and protection he or she needs to develop and grow inside your uterus.

The extra blood and fluid circulating around your body, for example, is needed to carry oxygen and nutrients to your little one via the placenta (which itself adds around a kilogram to your weight while you’re pregnant).

The amniotic fluid helps keep your foetus at the right temperature and cushions him or her from any knocks or bumps.

In fact, most of this extra weight amounts to a complete life support system for your little one – how amazing is that?

Of course, you’ll lose most of the pregnancy weight when your baby is born, but you will still need those extra fat stores to fuel breast milk production.

How Many Extra Calories Do You Need?

During the first trimester your body probably won’t need any extra calories to support your growing baby. If you struggle with morning sickness, you might even find it difficult to keep down some of the food you eat during the early stages of pregnancy.

Based on the baseline recommendation of eating 2000 calories a day when not pregnant, this is a rough breakdown of how many extra calories you should take in for gradual, healthy weight gain by trimester:

  • First trimester: No extra calories needed.

  • Second trimester: No extra calories needed.

  • Third trimester: Around 200 extra calories per day.

How to Eat Healthily While Pregnant

Do not diet while you’re pregnant but be mindful of the foods you consume. Make sure you eat a variety of nutritious, healthy food like fruits, vegetables, proteins, wholegrain or high fibre carbohydrates and dairy products.

If you have food intolerances or you follow a special diet, your doctor will be able to help you tailor your diet to ensure you’re getting the nutrients you need. In some cases, your doctor may recommend you take extra prenatal vitamins if you’re not getting enough of certain vitamins or minerals through diet alone.

Resist the temptation to ‘eat for two’. You definitely don’t need to indulge in double portions of chocolate and ice cream to nourish your growing baby. Your GP or midwife can help you follow a healthy pregnancy nutrition plan and give you advice on a target weight based on your starting weight.

If you’re overweight or underweight, your midwife may give you some extra nutrition advice so both you and your little one stay healthy throughout the duration of your pregnancy.

By the way, there are some foods you should avoid eating while pregnant, so read up on them too!


You put on most of the extra weight you gain in pregnancy after 20 weeks, so you’re likely to see the biggest increase in weight in the second half of the second trimester and the third trimester.

The most important thing during your pregnancy is your health and that of your baby. Each mum-to-be is different, so listen to your body and don't be afraid to ask for help from your doctor or midwife about what rate of pregnancy weight gain is best for you.

How we wrote this article
The information in this article is based on the expert advice found in trusted medical and government sources, such as the National Health Service (NHS). You can find a full list of sources used for this article below.
The content on this page should not replace professional medical advice. Always consult medical professionals for full diagnosis and treatment.

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