Pregnancy is an exciting, yet complicated time.
There is so much to learn and sooooo many questions.
Understanding how much weight you should gain during pregnancy might be one of the questions that comes into your head. Let’s have a look at the real answer to this question (and ignore the old wives’ tales).
There is no one-size-fits-all to pregnancy weight gain
All women are different and each pregnancy is different.
There is no “ideal” weight gain during pregnancy. The recommendations even vary depending on where in the world you live.
In fact, the same woman can gain weight in a different way in their first pregnancy to their second pregnancy, so you can’t even use your own experience as a definitive guide!
The amount of weight you should gain while pregnant is dependent on various factors. Your Body Mass Index (BMI) before pregnancy (or at the very start of your pregnancy) is one of the most important factors.
BMI Calculation
To find out what your BMI is, plug your details into the calculator below and it will calculate it for you.
Or if you want to geek out and do the calculation yourself, here is the equation:
BMI = weight (kg) / height (m)2
For example: Mary weighs 60kg and is 1.7m tall. Her calculation would be:
60kg / (1.7m x 1.7m) = 20.7
You can then check your BMI against the below BMI chart.
In the above example, Mary falls within the “normal” BMI range: 18.5 – 24.9
Weight gain during pregnancy BMI chart
Once you know your starting BMI you can use the charts below to determine how much weight the Institute for Medicine recommends you should gain during your pregnancy.
Single Pregnancy
Twin Pregnancy
If you are pregnant with triplets or more, talk to your health care provider about your weight gain goals.
Please be aware that these numbers are just recommendations and have come under some criticism for being on the high side. Also, depending where you in the world you live, the recommendations seem to vary.
I, for example, started my pregnancy with a normal BMI and gained 10kg during my pregnancy. The recommendation from the Institute of Medicine is to gain between 11.5 – 16 kg. However if you look at the NHS website from the UK, you’ll see that my weight gain actually falls within their general pregnancy weight gain recommendations.
So I guess what I want to say is don’t cling onto the numbers in the above chart. Every body and every pregnancy will be different. Work with your health care provider and don’t get too obsessed with the exact numbers.
If you’re wondering when the weight gain happens, below you will find links to articles with details on weight gain during each trimester.
Where does the extra weight during pregnancy come from?
It may feel like all the weight is in your watermelon-sized belly, but there are actually many factors that lead to the overall weight gain during pregnancy.
Below is a very rough breakdown of where the extra weight comes from (based on weight gain for women who start pregnancy with a normal BMI)
| Baby | 2.5 – 4.5 kg | 5.5 – 10 pounds |
| Placenta | 0.7 kg | 1.5 pounds |
| Uterus | 1 kg | 2 pounds |
| Amniotic fluid | 1 kg | 2 pounds |
| Breast tissue | 1 kg | 2 pounds |
| Fluid volume | 2 kg | 4 pounds |
| Blood volume | 2 kg | 4 pounds |
| Stores of fat for breastfeeding | 2.2 – 4kg | 5 – 9 pounds |
| TOTAL | 12.4 – 16.2 kg | 26 – 34.5 pounds |
How to monitor your weight gain during pregnancy
If you have scales at home it is easy to monitor your own weight.
Below are some guidelines to use if you want to track your own weight:
- Use the same scales each time
- Weigh yourself at the same time of day every time
- Wear the same clothes (or weight yourself when you are naked)
- Only weigh yourself once a week every 2 weeks. Do not weigh yourself every day – changes in fluid levels cause your weight to fluctuate and will probably cause more stress than needed!
How to gain the “right” amount of weight during pregnancy
How much weight you should gain while pregnant will be different for every single individual.
The best way to ensure you gain weight in a safe and sustainable way during pregnancy is:
- Eat a nutritious, well-balanced diet, rich in fruit and vegetables, wholegrain foods, legumes, lean meat and fish
- Avoid highly processed junk and snack foods
- Exercise regularly
- Drink plenty of water
More on nutrition
One day I will write a lot more about nutrition during pregnancy. For now there are a few links below to some resources to get you started.
If you are interested to dig into the details of nutrition during pregnancy, the “Your Pregnancy Nutrition Guide” by Henrietta Norton is a good option.
If you just want to read a short blog post with more details about the different food groups, this post on tommys.org gives a concise overview. There is also a short article with some specific details for special diets.
This whattoexpect.com article also has some excellent tips on foods to focus on during pregnancy.
…and don’t forget, you can find more information on trimester-by-trimester weight gain in these posts:
More on exercise
In time I will write a lot more on the topic of exercise during pregnancy (and once the baby arrives).
For now here are links to some good information to get you started:
whattoexpect.com – exercises to avoid
If you enjoy group fitness, you could consider joining a class offering pregnancy specific workouts (such as www.mominbalance.com).
Or you may be able to continue with your current group fitness class. Just be sure to discuss it with the instructor – they may need to adapt some exercises for you.
If you prefer to workout on your own at home, my friend and bootcamp partner, Amparo, developed an app-based training program for during pregnancy which I can highly recommend! Check out her website here.
Why excessive pregnancy weight gain isn’t a good idea
Gaining too much weight during pregnancy may increase the risks of:
- Having a large baby
- Caesarean section
- Gestational diabetes
- Pregnancy related high-blood pressure (preeclampsia)
- Difficulty in losing the excess weight postpartum
An important note: if you experience sudden weight gain during pregnancy, and it doesn’t seem to be related to overeating, you should contact your healthcare provider. It could be a sign of preeclampsia.
Conclusion
There is no one size fits all when it comes to how much weight to gain while pregnant.
Your starting BMI (Body Mass Index) will be a big factor when it comes to how much weight you need to gain: if you start off underweight, you will need to gain more weight during pregnancy than someone who is obese when they conceive.
Weight gain during pregnancy is inevitable and healthy. It is just important to keep it at a reasonable level and not buy into the myth that you can “eat for two”.
You don’t need to get hung up on every single kg or pound, but if the number on the scale suddenly sky rockets (or doesn’t move at all for several weeks), then it’s time to check in with the doctor.
How is your pregnancy weight gain going? Do you have any other questions about how much weight you should gain while pregnant?