Healthy weight gain during pregnancy

It is normal to gain weight during your pregnancy. This is due to the growth of the baby and placenta (afterbirth).

A healthy weight gain helps your uterus (womb), placenta and baby to grow. But you should avoid gaining too much weight during pregnancy.

If you are a healthy weight before you become pregnant, expect to gain 0.5kg per week in the second and third trimesters.

If you are underweight, you may need to gain more weight. If you are overweight, you may need to gain less. Your doctor or midwife will tell you.

Why a healthy weight gain is important

You and your baby will both benefit if you maintain a healthy weight.

Benefits for your baby

Benefits for your baby of a healthy weight gain:

  • Supply of oxygen and nutrients.
  • Lower risk of complications at birth.
  • More likely to be born at a healthy weight.
  • Less risk of medical problems such as diabetes in later life.

Benefits for you

Benefits of a healthy weight gain for you:

  • You will feel healthier and have more energy.
  • Be a healthier weight after your baby is born.
  • Reduce the risk of complications during pregnancy and birth.
  • It helps to prepare your body for breastfeeding.

How many calories you need

Most women don't need extra calories during the first trimester of pregnancy. You will need an extra 200 calories a day in the second and third trimester. This is roughly the same as 2 slices of bread.

Extra food servings

You can include an extra 2 to 3 servings a day from the food pyramid in the second and third trimester. This is to allow for the slight increase in energy needed.

This could include a serving of fruit, baked beans, a glass of milk or 20g of almonds. Other examples include a slice of bread, a tin of salmon, yogurt or 2 rye crackers with light cheese.

Healthy eating during pregnancy

Pregnancy weight gain

Most pregnancy weight gain happens in the second and third trimesters. A healthy weight gain depends on your weight before you became pregnant. If you were a healthy weight before, expect to gain 0.5kg per week in the second and third trimesters.


Don't try to lose weight by going on a diet. Instead, focus on healthy eating and staying active.

If you are underweight

Being underweight increases the chances of a premature birth for your baby. It also increases the chances of your baby having a low-weight at birth.

You may also suffer from anaemia (low amount of iron in the blood). You may need to gain more weight to bring you to a healthy weight.

Your midwife or GP will check your weight. They will tell you how much weight you should gain for a healthy pregnancy.

If you are overweight or obese

If you are overweight or obese, you have a greater risk of developing gestational diabetes. You are also at a greater risk of high blood pressure during pregnancy.

There are also some risks to your baby. These include excessive birth weight. Your baby may be born with low blood sugars or breathing problems.

Losing weight is not recommended when you are pregnant.

If you are worried that you are overweight or obese:

  • talk to your GP, midwife or obstetrician about ways to reduce the risk to you and your baby
  • make healthy changes to what you eat
  • exercise
  • talk with your obstetrician or midwife about the safest way, and place, for you to give birth.

Page last reviewed: 26 March 2018
Next review due: 26 March 2021