Weight gain during pregnancy

Putting on weight is a normal and unavoidable part of pregnancy. ‘Eating for two’ has become an often-repeated mantra that seems to have followed pregnant women around for decades, but while it sounds like it might make sense, it couldn’t be further from the truth.

Every woman is different, and there are many factors that affect how much weight you put on, but it’s true for all pregnant women that uncontrolled eating and weight gain can cause real problems down the track. Here's how to keep it in check.

What’s the ideal amount?

The ideal amount of weight gain during pregnancy very much depends on your pre-pregnancy weight. It’s usually calculated based on your body mass index (BMI), but as a guide, women within the healthy weight range (BMI 18.5-24.9) should aim to gain somewhere between 11.5 and 16 kg. It’s recommended that women who are overweight or obese gain between 5 and 11.5 kg, whereas women who are underweight should look to gain between 12.5 and 18 kg.

How much weight should you gain during pregnancy?

Use our healthy weight gain during pregnancy calculator to check that you're on track, from conception to delivery.

Try the calculator

How much more do you need to eat?

In the first trimester, there’s no need to increase how much you eat — just make sure you eat plenty of foods from the five different food groups, especially those that are rich in folate, iodine, protein, iron and zinc.

After you pass the 12-week mark you will need to eat a bit more. If you are in the healthy weight range, you’ll need about the same amount of extra calories that you’d find in a cheese and tomato sandwich on whole grain bread—or peanut-butter and banana on whole grain, if that’s more your style. If your body mass index fell into the obese range before pregnancy, you’d need to eat about as much energy/kilojoules as you’d find in one slice of bread or two apples—according to the New Zealand guidelines for healthy weight gain in pregnancy, which were published in 2014 and are referred to on the Royal Australian and New Zealand College of Obstetricians and Gynaecologists website.

Stay active during pregnancy

Staying fit and active is important throughout your life, and almost all women can and should exercise throughout their pregnancy. As well as helping you to maintain a healthy weight, which will make it easier for you to return to your pre-pregnancy weight, regular exercise also means you’re less likely to develop gestational diabetes. For more tips on how to stay active and healthy during pregnancy, read the article 'How to exercise safely during pregnancy'.