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 womb, placenta and baby to grow. But it's important to manage your weight during pregnancy.
If you have a healthy weight before you become pregnant, expect to gain 0.5kg per week in the second and third trimesters.
If you had underweight before you were pregnant, you may need to gain more weight. If you are pregnant with more than 1 baby, such as a twin pregnancy, then you may also need to gain more weight.
If you have excess weight before you become pregnant, you may need to discuss healthy weight changes with your midwife, GP or obstetrician.
Why healthy weight gain is important
You and your baby will both benefit if you maintain a healthy weight gain.
Benefits for your baby of a healthy weight gain
- Better 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 of a healthy weight gain for you
- You will feel healthier and have more energy.
- You will have a healthier weight after your baby is born.
- You will have a lower risk of complications during pregnancy and birth.
- It helps to prepare your body for breastfeeding.
Calories and dieting during pregnancy
Most women do not need extra calories during the first trimester of pregnancy.
Most women will need:
- around 250 extra calories in the second trimester
- up to 500 extra calories in the third trimester
Most weight gain happens in the second and third trimester. The amount of weight gain that is healthy for you will depend on your weight before your pregnancy.
Do not try to lose weight by going on a diet. Instead, focus on healthy eating and staying active.
Extra food servings
In the second and third trimester you can include an extra 2 to 3 servings a day of nourishing foods from the food pyramid. This will give you a small increase in energy and the nutrients you need.
This could include:
- a serving of fruit
- baked beans
- a glass of milk
- 20g of almonds
- a slice of bread
- a tin of salmon
- 125g of yoghurt
- 2 rye crackers with light cheese
If you have underweight
Having 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 be at risk of not having enough of some nutrients.
In this case, you may need to gain more weight to:
- increase your weight to a healthy weight
- make sure you are getting the nutrition you and your baby need during pregnancy
Your midwife, GP or obstetrician will ask to check your weight. They will tell you how much weight to gain for a healthy pregnancy.
If you have excess weight
If you have excess weight, you have a greater risk of developing:
There are also some risks to your baby. These include a high birth weight, or your baby being born with low blood sugar or breathing problems.
Dieting to lose weight is not recommended when pregnant. Focus instead on healthy eating and moderate physical activity.
If you are worried about your weight affecting your health, and that of your baby:
- talk with your GP, midwife or obstetrician - they may be able to support you with advice, or refer you to a dietitian or physiotherapist for extra support
- eat well - which means eating regular nutritious meals and snacks
- stay physically active
- talk with your obstetrician or midwife about the safest way and place for you to give birth