Healthy weight gain during pregnancy

RosemaryM 17By Rosemary Marchese

Editor, B.A. Applied Sci (Physiotherapist)

Ecstatic. Nauseous. Exhausted. There are so many variations to what a pregnant woman may experience at any one time; however, one experience that remains common among all pregnant women is weight gain. And that is normal. But how much weight is healthy during pregnancy?

There are still differing worldwide opinions on ‘how much’ weight a woman should gain during pregnancy. To put it down to exact figures is really not appropriate because there are too many variables that can affect weight gain. On the flip side there is also the concern that some women naturally don’t tend to put on much weight at all. Is there a weight gain that is too little, then?

Women who are underweight before pregnancy may need to gain a few more kilos than others, but that’s not an excuse to binge on donuts! It’s important to nourish your body by adopting a healthy eating plan. Pregnant women who do not put on enough weight during pregnancy may be at higher risk of:

  • premature birth
  • lower birth weight of baby
  • birth defects.

One of the ways you can gauge how much weight you should put on is through the use of your body mass index (BMI). This gives you a relationship between your weight and your height, giving you some indication of whether you are in a healthy weight range. However, be warned that there are problems with this method. Body weight is made up of more than just fat. There is water, muscle, organs and so much more. Muscle weighs more than fat, too, so if you’re really healthy, and quite lean and toned, then your weight may indeed put you in the ‘overweight’ category for BMI when you are actually not overweight at all. It’s important to discuss this with your obstetrician.

How much weight to gain during pregnancy

Pre-pregnancy weight= ____kg

Height = _____m (e.g. 156cm is 1.56m)

BMI = weight/(height x height) = _____kg/m2

We use the National Health and Medical Research Council recommendations for weight gain below. So if your BMI was:

  • Less than 18.5 (underweight), you should gain between 12.5 kg and 18 kg
  • 18.5 to 24.9 (normal weight), you should gain between 11.5 kg and 16 kg
  • 25 to 29.9 (overweight), you should gain between 7 kg and 11.5 kg
  • 30 or more (obese), you should gain between 5 kg and 9 kg.

Of course, the weight gain will differ if you’re carrying more than one baby! Talk to your obstetrician about your individual circumstances.

When you gain too much

If you gain excessive weight during pregnancy and you don’t lose the weight after the baby is born, then the extra weight may increase your lifelong health risks. Excessive weight gain during pregnancy also increases the risk of health problems for the baby at birth and childhood obesity as well.

Where does the pregnancy weight go?

Let’s say that your baby weighs about 3 to 3.6 kg. That weight may account for only a small amount of the weight gained during pregnancy. So where does all the rest come from? Let’s take a look (these are approximate values only):

  • baby: 3 to 3.6 kg
  • larger breasts: 1 kg
  • uterus: 1 kg
  • placenta: 0.7 kg
  • amniotic fluid: 1 kg
  • increased blood volume: 1.4 to 1.8 kg
  • increased fluid volume: 1.4 to 1.8 kg
  • fat stores: 2.7 to 3.6 kg.

First trimester weight gains

The reality is that women don’t need to put on much weight at all during the first three months of pregnancy. This is great news for those suffering from morning sickness and worrying about weight loss (although see your doctor if you are concerned). For women who start out at a normal weight, you need to gain only about 2 kg in the first few months of pregnancy. The ‘eating for two’ catchphrase is a myth . So, don’t double your food intake whatever you do! If you were underweight before pregnancy, then the approach you take needs to be discussed in more detail with your obstetrician.

Unfortunately, some women suffer from constant nausea during pregnancy, especially so during the first trimester, and this can be eased by regular snacking. Just take care to ensure the snacks are healthy and try to not overindulge in processed and unhealthy snacks. Most are loaded with sugars and eating them will exacerbate weight gain!

Second and third trimester weight gains

Steady weight gain is more important during trimesters two and three. It will generally mean gaining about 1.4 to 1.8 kg per month until delivery. This gain is especially important if you start off at a healthy weight or are underweight. It roughly equates to consuming about an extra 300 calories per day – but it’s not an excuse to binge! A half-sandwich and a glass of milk can help you meet this goal. For those who started pregnancy underweight, it’s wise to talk to your obstetrician for further advice about these trimesters.

Swap crappy food for nourishment

So, what can be on your menu? It’s really easy to add the extra calories required during pregnancy by eating junk food. A donut would more than do the trick, right? But it won’t nourish your body or the baby. The healthiest approach is to avoid overeating and choose nutrient-rich options. Suggestions include:

  • swapping white bread and pasta for wholegrain varieties
  • eat an apple instead of a purchased muffin
  • make your own salads with legumes for lunch rather than buying a fried takeaway meal.

The National Health and Medical Research Council has published the Dietary Guidelines for Australian Adults and this includes some recommendations for pregnant women. Take a look at the table below.

FoodsRecommended serves per dayExamples of one serve
Cereals, breads, rice, pasta, noodles8.51 slice of bread

½ cup cooked rice

Pasta or noodles

Fruit21 medium apple

2 small plums

½ cup of fruit juice

Vegetables and legumes5-6½ cup cooked spinach

1 cup raw leafy greens

½ medium potato

Lean meat, fish, poultry, eggs, nuts and legumes3.590-100 gm raw lean meat or chicken

2 small eggs

Milk, yoghurt and cheese2.51 cup low-fat milk

2 slices or 4 x 3×2 cm pieces of hard cheese

Drink plenty of water

Keeping fit and active during pregnancy

As long as your pregnancy is progressing normally and your obstetrician is happy for you to exercise, then regular exercise is a great way to control your weight. It also will provide you with so many other benefits including:

  • improved sleep
  • easier labour
  • quicker return to healthy weight after birth.

Once you have the okay from your doctor to exercise then aim for at least 30 minutes of moderate-intensity exercise on most, if not all days of the week. Moderate-intensity exercise means you should be able to hold a conversation while exercising, without being short of breath. You may like to try one or more of the following:

  • swimming
  • walking
  • cycling
  • yoga
  • pilates
  • dancing
  • water aerobics
  • pregnancy exercise classes.

While strength training was once considered to be almost taboo during pregnancy, with only ‘light weights’ at the most recommended, opinions are starting to change. The benefits of resistance training during pregnancy are now being more and more realised. Resistance training is a great way to ensure that your body is lean because the muscle will use the energy during your training and also after your workout is finished. People who have more muscle on them have a higher metabolic rate, which means they will use more energy, even during sleep, than someone with a lower metabolic rate.

There’s no one-size-fits-all approach to a healthy pregnancy. Regular exercise and healthy eating, however, is an essential point of discussion with your obstetrician.



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