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Healthy weight gain during pregnancy

14 April 2021 Blog
A common concern from women during their pregnancy is how much weight they should gain. Obstetrician and Gynaecologist Dr Debby Utama explains the optimal weight gain for a healthy mum and baby.

The reality is that weight gain is healthy and expected during pregnancy but the old adage that you are ‘eating for two’ now no longer applies.

Striking this balance is important as we know that women who are underweight during their pregnancy risk a miscarriage, low birth weight for baby and preterm birth. 

Alternatively, women who are overweight (a pre pregnancy BMI of 30 or more) during pregnancy have increased health risks to both mother and baby such as gestational diabetes, pre-eclampsia and stillbirth. The baby also tends to be a larger size and this can result in complications during birth or increased risk of requiring an emergency caesarean. 

Everyone is different and your care provider will be able to advise on your optimal weight as you progress through the stages of pregnancy based on your pre-pregnancy body mass index (BMI). 

As a general rule, the smaller your pre-pregnancy BMI the more weight you need to gain and the larger your BMI you need to gain less. Visit the RACGP BMI chart for more information. 

Weight gain to expect for a single pregnancy 

Please note that this will differ if you are expecting multiple babies.

First Trimester: 
Gain around 1.5 kg over the whole three month period.

Second Trimester: 
Gain around 1 to 1.5kg per month during this trimester. 

Third Trimester: 
While it may feel like you are gaining more, generally you should continue to gain 1 to 1.5kg per month until birth. 

Fourth Trimester:
After the birth of your baby you will lose the weight of the baby, placenta, blood and amniotic fluid which amounts to around 6 kg. It may take six to 12 months to lose additional weight gained during pregnancy and this is normal. Getting back to healthy weight post pregnancy can be important for any future pregnancies and long term health.

Read some of our recent blogs about a healthy diet and exercise for conception and pregnancy.

Dr Debby Utama - Obstetrician and gynaecologist
Debby is a qualified Obstetrician and Gynaecologist at St John of God Berwick Hospital. She believes in holistic care and empowering her patients to achieve individualised evidence based care.