When it comes to pregnancy, your doctor will recommend a weight gain target that’s right for you. So, regardless of what answer we give you here, make sure you stick with that guideline.
Every pregnant body is different and the amount you gain is heavily influenced by your pre-pregnancy weight. Whether you’re carrying more than one baby, craving more food than usual, or being struck down by morning sickness, these are all things that can change what your expected weight will be.
That said, based on general guidelines, you can expect a weight gain of between 11.5kg and 16kg — but of course, things are not always black and white.
Pregnancy weight gain: where does it go?
New York Times best-seller, ‘What to Expect When You’re Expecting’ breaks down the weight gain like this:
- Baby - 3.4kg
- Placenta - 0.7kg
- Amniotic fluid - 0.9kg
- Uterine enlargement - 0.9kg
- Mum’s breast tissue - 0.9kg
- Mum’s blood volume - 1.8kg
- Fluid in mum’s tissue - 1.8kg
- Mum’s fat stores - 3.17kg
This equals a weight gain average of 13.6kg, but again, take this with a grain of salt. Everyone is different.
What's a normal weight gain in pregnancy?
Well, 13.6kg is a good start, and if you’re having twins or triplets, you can expect 11-24kg .
There are also useful guidelines that give pregnant women an idea of how much weight they can expect to gain throughout pregnancy, which has something to do with their body mass index (BMI) — and we'll get to that shortly.
According to Diabetes Australia, about 1 in 3 women start their pregnancy overweight, which can cause problems for both the mother and the baby. It’s recommended to start your pregnancy when you are within the healthy weight range, which means a BMI of 18.5-24.9.
How much can I gain based on my current weight?
According to What to Expect When You’re Expecting, the recommended amount of weight you should gain during pregnancy is based on your BMI before you become pregnant. Again, if you have questions about this, it’s best to talk to your doctor, but generally:
- If your pre-pregnancy BMI is less than 18.5, your recommended weight gain is 12.5-18kg;
- If your pre-pregnancy BMI is 18.5 to 24.9, your recommended weight gain is 11.5-16kg;
- If your pre-pregnancy BMI is 25 to 29.9, your recommended weight gain is 7-11.5kg;
- If your pre-pregnancy BMI is above 30, your recommended weight gain is 5-9kg.
If you're unsure what your BMI is, you can simply use an online calculator like Juniper's. All you need to do is input your weight and height, and you'll get your result.
How much weight is normal to put on during each trimester?
It is normal and healthy to gradually gain weight during pregnancy, with 'gradually' being the keyword here.
The weight gain doesn't happen at the same pace throughout the entire 9 months. In the beginning, when the baby is still tiny, it will likely be slow and, as the baby grows, it will speed up.
- First trimester (up to 3 months): All women can expect to gain 1-2kg 
- Second and third trimesters (3-9months): The rate of weight gain is dependent on your BMI before becoming pregnant :
- BMI <18.5: 500g per week;
- BMI 18.5 to 24.9: 400g per week;
- BMI above 25: less than 300g per week
Apart from your BMI, other factors may influence how much weight you put on, including your dietary habits, how much exercise you do during pregnancy, any food cravings or aversions, and fluid retention.
What are the dangers of putting on too much weight during pregnancy?
Gaining too much weight can affect not only your health but your baby's health as well.
It increases your risk of several complications including gestational diabetes, which can put you at a higher risk of high blood pressure, low blood sugar, and developing type 2 diabetes later on . It also increases your baby's odds of having diabetes and breathing difficulties, and in some cases, it can lead to preterm birth .
Those who gain too much weight during pregnancy are also more likely to need to have a C-section.
How can I manage weight gain during pregnancy?
Much like when you're not pregnant, achieving a healthy weight gain when you're expecting is about maintaining healthy lifestyle habits:
- Eat a healthy diet full of whole grains, fresh fruits and vegetables, healthy fats like nuts, avocado, and olive oil, and high-protein foods like lean meat, eggs, and tofu.
- Limit your intake of fast food, unhealthy snacks like chips, cake or cookies, and soft drinks.
- Eat smaller, but more regular meals and snacks. This way you'll keep your hunger levels in check without overeating.
- Check with your doctor how many calories you should be eating (which will change from trimester to trimester).
- Drink plenty of water.
- Go on a daily walk — even if just for 10 minutes.
- Aim for 150 minutes of moderate exercise a week (but make sure to check with your doctor what is and isn't safe for you and the bub) .
What if I'm not gaining enough weight?
Not gaining enough weight isn't healthy either. If it's something you've been struggling with for more than 2 weeks in a row between the 4-8 month mark of your pregnancy — and unless your doctor has you on a schedule to lose weight — we recommend you get professional help.
Again, leading a healthy, nutritious diet is essential for healthy weight gain but in this scenario, supplementing may also be helpful to make sure you're still getting all the essential nutrients and vitamins you need.
Kin's Prenatal Vitamin is packed with 12 highly bioavailable ingredients, including methylated folate, omega-3, iron, and iodine, to give your baby the best possible start.
If it is morning sickness that's affecting your appetite and causing you to skip meals, give Kin's Morning Sickness Tea a try. Made with organic ginger, peppermint, and subtle aromatics, it will help curb nausea so you can go back to eating your regular diet.
When to speak to your doctor
If you feel like you're experiencing increased weight gain, particularly in the second and third trimesters, check in with your doctor — especially if you notice severe swelling in the legs and feet, or puffiness in your face and hands. Same thing if you're not gaining enough or even losing weight.
Gaining weight during pregnancy is normal and necessary, but remember: keeping it in check will help you grow a healthy baby — and what's more important than that?