Weight gain and other changes to your body

If you’ve always watched your weight, it can feel strange to keep putting weight on. Even though, logically, you know your weight should increase, you can still feel funny about it. The fact is that slow, gradual weight gain is the sign of a healthy pregnancy.

Healthy weight gain

There is not a 'right' amount of weight to put on but somewhere between 9 and 16kg (19 and 35 pounds) is normal if you are expecting one baby. It will vary from woman to woman. 

About half of women now go into pregnancy and are already overweight or obese and a small number are underweight. It is damaging to the baby's health to diet in pregnancy. If you are overweight you should not lose weight but aim to gain at least 5 kg during the pregnancy. It is even more important not to 'eat for two' or gain weight excessively.

How the weight is made up:

  • baby: 2.5-4kg (5 to 9 pounds)
  • placenta: 0.5-1kg (1 to 2 pounds)
  • amniotic fluid: 1.5-2.5kg (3 to 5 pounds)
  • increased blood volume and fluids (yours): 2-4kg (4 to 9 pounds)
  • extra weight of uterus, breasts and fat and protein stores: 2-5kg (4 to 11 pounds).

You'll be weighed at the beginning of your pregnancy so that the midwives or obstetricians have something to compare your weight to as the pregnancy develops. Most weight gain is in the middle part of the pregnancy (four to seven months), although you may find you put on a fair bit near the start because of fluid retention. Some women don't gain any weight at all in the last two to three weeks.

Only about a third of the extra weight is due to the baby, amniotic fluid and placenta. The rest is the extra weight you need to support the pregnancy and prepare for breastfeeding afterwards. Breastfeeding your baby for as long as possible will help you to lose weight and this will help you get healthy for your next pregnancy.

Your midwife will be keeping an eye out for rapid weight gain in the last ten weeks of pregnancy as this can be one of the signs of pre-eclampsia.

Healthy eating

As you move through your pregnancy, you may find you get hungrier, especially between meals, so it can be tempting to reach for the crisps and chocolate. Now and again this is fine, but you may find it useful to carry healthy snacks around with you to satisfy your food cravings and avoid temptation. It’s important to eat well during pregnancy to give your baby the best start in life. For further information, visit our Eating well section.

You should aim to have about eight glasses of water a day, jazz it up with ice and a slice of lemon. Or try diluted fruit juice or very weak cordial.

Pelvic floor exercises

Around now you may begin to realise why you should be doing pelvic-floor exercises (in other words, you may have a little leak of urine). Doing them now is important to get those vital muscles in shape for the rest of pregnancy and beyond.

Stretch marks

You may develop stretch marks, thin lines on the skin caused by collagen (the thing that makes our skin elastic and stretchy) tearing as your body expands to cope with pregnancy. These can look quite red but will fade to become faint, silvery lines afterwards. A healthy diet and not putting on weight too quickly may help.

Other physical changes

  • Your skin may show some changes. You may find you develop skin tags, which are little bits of extra skin, particularly at points where your clothing is rubbing. These are nothing to worry about.
  • You may suffer from rashes or spots. Wearing cotton clothing may ease heat rashes.
  • You may find your nipples, freckles and moles get darker.
Last Updated: 31 January 2018
We use cookies to help improve this website. You can change your cookie settings at any time. Otherwise, we'll assume you're OK to continue. Don't show this message again