Weight gain in pregnancy

Pregnant woman on scalesOne thing is for certain: you're going to gain some weight when you are pregnant. For some women this can be a blessed relief, taking it as an excuse to eat what they want, playing the old 'eating for two' card. Others may find the weight gain alarming and feel out of control of their bodies.

Whichever way you feel about it, weight gain is necessary during pregnancy to help your baby grow and your body will store more fat than usual in preparation for being able to produce milk to feed your baby after birth.

How much weight gain can you expect?

There are many factors that will determine how much weight you will put on during pregnancy - your pre-pregnancy weight, the amount you eat and your genetic make-up being some of them.

According to NHS Choices, most women put on between 8kg to 14kg (17.5lb to 30lb) and most of this is after week 20. About a third of this will be your baby, placenta and the amniotic fluid surrounding your baby. The rest of the weight gain will be:

  • Your boobs, alone can put on over 1kg (3lbs) as they prepare for breastfeeding
  • Blood volume
  • Extra fluid in the body
  • An increase in the muscle layer of the uterus
  • Increased fat stores.

What happens if you are overweight or underweight during pregnancy?

Being underweight or overweight can be harmful to the development of your baby. Women who are malnourished before they become pregnant are more prone to miscarriage, premature birth or having babies with a low birth-weight.

Those who are overweight before they get pregnant run the risk of complications such as:

The NHS says if women who are the recommended weight for their height before they're pregnant gain between 10 and 12.5kg (22-28lb) they'll have a lower risk of complications. If you were underweight before, with a BMI less than 18.5 you should put on a bit more (13kg–18kg) and if you are overweight (BMI 25–29.9), put on a little less (7Kg–11kg). Obese women (BMI more than 30) should only put on 5kg–9kg.

You should put on weight steadily throughout your pregnancy and rapid weight gain can signify a problem such as pre-eclampsia. It used to be that women were weighed at every antenatal appointment but this is unlikely to happen now, your midwife will measure your bump though and keep an eye out for any unusual weight gain.

Your midwife or GP will be able to give you advice if you are either underweight or overweight. Try to eat sensibly and healthily and on no account try to lose weight when you're pregnant.

How you can control your weight in pregnancy

The best thing to do is to eat sensibly choosing a good selection of fresh healthy foods. You know the sort of thing: fruit, veg, carbs, protein, lean meats, fish and not too much red meat, sugars and excessively fatty or over-processed foods.

Try to stay active, drink lots of water and take cues from your body about when and how much to eat. As a rough guide you should aim to take in about 2,000 calories a day with an extra 200 in the last trimester.

The eating for two thing, while being a good excuse to indulge, should really be discarded. You need to eat a bit more, yes, but don't go mad.

Most women lose about two-thirds of the weight they have put on within a month of giving birth but the rest can be difficult to shift post-pregnancy and can cause self esteem and confidence issues. Some women find it easier to lose weight when they stop breastfeeding. Try to lay off the empty calories and be sensible in your approach to food and choose the best building blocks to create your baby.

What Mumsnetters say about weight gain during pregnancy 

  • I don't know anyone who only managed to put on a mere 2 stone. I put on at least four. I just think some of us are destined to put on more weight and there really isn't that much you can do about it. aloha
  • I thought I would feel beautiful - I just felt really, really fat. Mind you, I've had an issue most of my life with weight (even though I am now at a healthy weight) so for me it was a very psychological battle. SittingBull
  • I was constantly hungry when pregnant with my son and although I ate healthy foods and snacked on raw veg etc I gained 4 stone. I gave up reading the 'what you should have gained by now' guidelines as I found it can vary so much from woman to woman and my son turned out just fine. PussinJimmyChoos
  • I've found the weight doesn't go on uniformly like the charts suggest - it doesn't have to be 70% in the second half of pregnancy. You'll know if you're eating well (and as far as I'm concerned that does include a compulsory cake each day). Remember a lot of that weight is in your breasts and for me that was a bonus. Ninja
  • I'm a large lady and was a bit concerned - I'd put on close to a stone by 20 weeks and another 4lb by 30 weeks. But I have not been weighed at any appointments and if the professionals aren't worried, I'm not going to get hung up on it. AliP
  • Judging by my jeans, a lot of the weight is in my thighs! Monkey


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Last updated: about 2 months ago