Healthy Weight Gain

Healthy Weight Gain

What is a healthy rate of weight gain?

It is normal and healthy to gain weight during pregnancy.

In the 1^st trimester, you should expect to gain about 3-5 lbs.  During the 2^nd and 3^rd trimesters, you should expect to gain between ½ and 1 lb each week.  The picture below shows you how much weight you may gain in each part of your body.  Click here to see a print version.

Source: Health Canada.  Reproduced with the permission of the Minister of Public Works and Government Services Canada, 2010^©

The total amount of weight gain depends on your pre-pregnancy weight.  If you are underweight, you will need to gain more weight compared to someone who is overweight.  Read the next section on BMI to figure out which weight category you fall into.

What is BMI?

There is a calculation called the BMI (or body mass index) that can help you figure out how much weight you should gain during pregnancy.  The calculation is shown below:

For example, if you are 165 cm tall (or 1.65 m) and weigh 130 lbs (59 kg), your BMI would be equal to:

BMI = 59/(1.65 x 1.65) = 21.7.

If you look on the chart below, you can see that if your BMI is 21.7, you are considered to be normal weight, so for your pregnancy your total weight gain should be between 25 to 35 lbs (11.5 and 16.0 kg).  Talk to your doctor, nurse, or regional CPNP nutritionist if you would like to calculate your pre-pregnancy BMI or have questions about how to use it.

(Source: Health Canada Canadian Gestational Weight Gain Recommendations 2010)

 If you are a teenager…

Because your own body has not finished growing, you should try to aim to gain an amount of weight at the higher range of each weight group so that you have enough energy for yourself and your baby.  For example if you are underweight, you should aim to gain about 40 lbs by the end of your pregnancy; if you are obese, you should aim to gain about 20 lbs at the end of your pregnancy.  Do not use BMI to determine how much weight you should gain because BMI is not used for teenagers.

If you are having twins…

If you are having twins, you will need to gain more weight compared to someone who is only having a single baby.  In the 1^st trimester, you should aim to gain 2-3 kg (4-6 lbs).  In the 2^nd and 3^rd trimesters, you should aim to gain about 0.75 kg (1.5 lbs) per week.  It is also a good idea to see your Regional CPNP nutritionist to make sure you and your baby are getting enough nutrition.

(adapted from Health Canada: 2009 Institute of Medicine (IOM) Weight Gain for Twins)

If you are expecting triplets…

Your rate of weight gain throughout pregnancy should be about 0.75 kg (1.5 lbs) each week.  Your overall weight gain for the pregnancy should be about 23 kg (50 lbs).  If you are having triplets, you should see your Regional CPNP nutritionist to make sure you and your baby are getting enough nutrition.

Gaining too much or too little weight…

Gaining too much weight increases the risk of having a high birth weight baby.  This is linked to

• A long a difficult labour and birth
• More chance of a Caesarian delivery
• Increased risk of the baby dying
• Increased risk of the mother developing gestational diabetes
• Increased risk of the baby getting diabetes later in life

Not gaining enough weight increases the risk of having a low birth weight baby.  This is linked to

• The baby being born too early
• The baby not growing and developing properly
• The baby being sick and developing health problems that can last a lifetime
• The baby dying
• Problems with the mental and behavioural development of the baby

Source: Health Canada.  Reproduced with the permission of the Minister of Public Works and Government Services Canada, 2010^©

Questions

What can I do if I am gaining too much weight?

If you are gaining too much weight, choose more fruits and vegetables, lower fat milk products, leaner cuts of meat, poultry, and fish.  You can also eat less high fat foods (like butter, deep fried foods, and pastries), and foods high in sugar (like pop, candy, chocolate, pies and cakes).  Including physical activity daily is also important.  Talk to your doctor or nurse to determine how much and what type of exercise is most appropriate for you.  A healthy weight gain is best for you and your baby.

What are some reasons why I am not gaining enough weight?

You may not be gaining enough weight for a number of reasons.  Now that you are pregnant, your body needs more energy to support you and your growing baby.  If you are still unsure or have questions, contact your Regional CPNP nutritionist.

1. Not eating enough is most likely the reason you aren't gaining enough weight. Are you not eating enough because...

• Of the high cost of food?  If so, there are many ways to still get the proper nutrition on a smaller budget.  See Are You Getting Enough?.  You can also check with the CPNP program in your community because many of them will provide information on how to eat healthy when you are pregnant and provide food vouchers for healthy foods at a local store.
• You are feeling too nauseous to eat, not hungry, or are throwing up?  If so, try eating smaller, more frequent meals.  Also see what you can do to reduce nausea.
• You have been diagnosed with gestational diabetes and don't know what you can eat?  If so, talk to your Regional CPNP nutritionist.
• You are afraid to gain too much weight?  Weight gain is normal and healthy when you are pregnant.  If you are not getting enough, neither is your baby.  Pregnancy is not the time to think about weight loss.  See Healthy Weight Gain to see how much you should aim to gain. 
• You just don't know what to eat?  If so, talk to your CPNP worker, or Regional CPNP nutritionist for more information.  Also see Healthy Eating for more information.

2. Another common reason is smoking.  Smoking can also cause you to not gain enough weight because it affects your baby's growth.  Your baby may be growing more slowly because he or she is getting less oxygen and nutrients.  See Smoking and Pregnancy or How to Quit Smoking.  You can also talk to your doctor or nurse at your health center if you are thinking about quitting or cutting down.