The recommended weight gain in pregnancy ranges between 5-18kg. It depends on your ethnicity and pre-pregnancy body mass index (BMI).
How do I calculate
my body mass index (BMI)?
Your body mass index is calculated by dividing your pre-pregnancy weight (kg) by height (in metres squared). For example: if your pre-pregnancy weight is 80 kg and your height is 1.65m, your BMI is:
80 ÷ 1.62 ÷ 1.62 = 30.4
Alternatively, you can use an online calculator: https://www.healthdirect.gov.au/bmi-calculator
What weight range am I in?
Below are the medical definitions of weight ranges based on your pre-pregnancy BMI.
If you are of Caucasian descent:
- If your BMI is below 18.5, you are ‘underweight.’
- If your BMI is 18.5 to 24.9, you are in the ‘healthy weight range.’
- If your BMI is 25 to 29.9, you are ‘overweight.’
- If your BMI is more than 30, you are ‘obese.’
If you are of Asian descent:
- If your BMI is below 18.5, you are ‘underweight.’
- If your BMI is between 18.5 and 23, you are in the ‘healthy weight range.’
- If your BMI is between 23 and 27.5, you are ‘overweight.’
- If your BMI is greater than 27.5, you are ‘obese.’
How much weight should I gain during pregnancy?
Your recommended weight gain in pregnancy is linked to the weight range you were in before falling pregnant and your ethnicity:
Caucasian women
Pre-pregnancy BMI
Recommended weight gain
- BMI less than 18.5
12.5 to 18 kg - BMI between 18.5 and 25
11.5 and 16 kg - BMI between 25 and 30
7 to 11.5 kg - BMI of 30 or more
5 to 9 kg
Asian women
Pre-pregnancy BMI
Recommended weight gain
- BMI less than 18.5
12.5 to 18 kg - BMI between 18.5 and 23
11.5 and 16 kg - BMI between 23 and 27.5
7 to 11.5 kg - BMI greater than 27.5
5 to 9 kg
Alternatively, you can use this online calculator to see your recommended weight gain in pregnancy: https://www.gethealthynsw.com.au/healthier-you/healthy-in-pregnancy/pregnancy-weight-gain-calculator/
In which trimester do you gain the most weight?
You will put on the most weight during the third trimester, as this is when your baby gains the most weight. This is also the trimester in which your uterus, breasts, and placenta are growing at their most rapid rates. In the third trimester, your body accumulates extra fluid (most noticeably seen around your ankles) in preparation for labour.
What happens if I put on more weight than recommended in pregnancy?
Up to 50% of women exceed the recommended weight in pregnancy. If you exceed the recommended ranges, you are at a higher risk of developing conditions like high blood pressure, gestational diabetes, and pre-eclampsia. Your baby’s growth may also be affected. Larger babies can lead to potential complications at delivery, such as increased cesarean section rates, instrumental delivery rates, vaginal tearing, and shoulder dystocia (‘stuck shoulders’). If weight gain is an issue in your pregnancy, Dr. Porter will help you manage it and monitor your baby’s growth with ultrasound scans.
What happens if I put on less weight than recommended during pregnancy?
If you are not putting on the recommended minimum weight during pregnancy, but you are eating regular meals and maintaining a balanced diet, it is unlikely you will have any problems. The concern if you are not gaining the recommended minimum weight in pregnancy is the possibility of not delivering the required nutrients to your baby. This may lead to your baby being small, potentially leading to complications in labour and later life. If you are not gaining or losing weight, Dr. Porter will check on your baby’s growth with ultrasound scans.
How can I control my weight gain during pregnancy?
The best way to control your weight gain during pregnancy is with diet (eat healthy, regular meals) and exercise (regular and moderate intensity). Dr. Porter has specific fact sheets about diet and exercise in pregnancy.
How much weight will I lose when the baby is born?
The average Weight loss for mothers after childbirth is approximately 6 kg. This is a combination of the amniotic fluid, placenta, and your baby’s weight.
