Print this topic

HealthInfo Waitaha Canterbury

Healthy weight gain in pregnancy

Keeping track of how much weight you gain in pregnancy is important for your health and your baby's health. This is especially important if you were underweight or overweight at the start of your pregnancy.

The hormones produced in pregnancy can make some women feel more hungry. So, it's important to keep an eye on the size of the portions you're eating.

Gaining too much weight in pregnancy increases your risk of:

It can also make it more difficult to get your weight back down after childbirth.

To work out how much weight you should gain, you need to know what your body mass index (BMI) was at the start of your pregnancy.

This table is a guide to how much weight you should gain based on your pre-pregnancy BMI.

Pre-pregnancy or early pregnancy (less than 10 weeks) BMI

Total weight gain range

Underweight (less than 18.5)

12.5 to 18 kg

Healthy weight (18.5 to 24.9)

11.5 to 16 kg

Slightly unhealthy weight (25 to 29.9)

7 to 11.5 kg

Very unhealthy weight: (30 and over)

5 to 9 kg

This table is a guide to how much weight you should gain if you're having twins.

Pre-pregnancy or early pregnancy (less than 10 weeks) BMI

Total weight gain range

Underweight (less than 18.5)

At least 17 kg

Healthy weight (18.5 to 24.9)

17 to 25 kg

Slightly unhealthy weight (25 to 29.9)

14 to 23 kg

Very unhealthy weight (30 and over)

9 to 11 kg

There are no recommendations for how much weight you should gain if you're having triplets, but doctors suggest that you gain at least 23 kg.

If you're concerned you're not gaining enough weight or too much weight talk to your LMC or GP.

The Healthy weight gain in pregnancy poster provides information about healthy levels of weight gain in pregnancy.

Health professionals recommend that you keep track of your weight while you're pregnant. If you like, you can use the table in the Healthy weight gain in pregnancy record to do this.

Your midwife or LMC may weigh you at intervals through your pregnancy or you may weigh yourself. If you have any concerns about your weight or nutrition, speak to your midwife, LMC or GP.

If you meet certain criteria, your LMC may give you information about Support for getting active or refer you to a healthy food and lifestyle education session. Christchurch Women's Hospital dietitians run the education sessions.

Written by HealthInfo clinical advisers. Last reviewed December 2021.

Page reference: 71335

Review key: HIPRC-41255