Holding 4

Staying Healthy During Pregnancy

Concerned about pregnancy weight gain? We look at the logistics and importance of maintaining a healthy weight during pregnancy.

Most women gain 11 to 16kg during pregnancy, and what’s surprising to many of them is that the baby typically accounts for little more than one-third of the weight gained.

Pregnancy is a unique time in which your body changes to meet the needs of your growing baby, and this also affects weight. Your body is now storing nutrients and more blood and other fluids. For example, uterine growth accounts for nearly 1kg, and the placenta, which provides nutrition for the baby, is about 0.7kg.

Here’s a Breakdown Of  Kilograms at Full Term for the Average Woman:

  • Baby: 3.5kg
  • Amniotic fluid: 0.9kg
  • Placenta: 0.7kg
  • Growth of uterus: 0.9kg
  • Growth of breasts: 1.1kg
  • Increased amount of blood: 1.5kg
  • Increased amount of other body fluids: 1.1kg
  • Nutrient stores (fat and protein): 3.1kg

What’s the Right Weight Gain for Me?

To work out a healthy target for weight gain in pregnancy, you’ll need to know your body mass index (BMI), which is calculated on your pre-pregnancy weight. The BMI measures your weight in relation to your height, and accurately indicates whether you’re in a healthy weight range.

To calculate your BMI, divide your weight in kilograms by your height in metres, squared.

A normal BMI is 20 to 24.9. A BMI of 25 to 29.9 means you’re overweight, while 30 or more represents obesity. Generally, if you’re underweight, it’s better to gain a bit more, while if you’re overweight, try to curb the weight gain a little during pregnancy. Here’s a guide, based on your BMI:

Weight status    BMI      Gain (kg)

Underweight      < 18.5      12.5 to 18
Normal          18.5-24.9      11.5 to 16
Overweight        25-29.9     7 to 11.5
Obese               > 30           5 to 9
Carrying twins   18.5-24.9   16 to 24
25-29.9     14 to 23
> 30            11 to 19

What Happens If I Put on Too Much Weight, or Not Enough?

Gaining a lot of weight isn’t good for you or the baby, and it can increase your risk of complications such as high blood pressure or gestational diabetes, and the baby is more likely to experience metabolic diseases such as diabetes. Women who put on too much extra weight during pregnancy will also find it harder to lose that weight after giving birth.

That said, this isn’t the time to go on a weight-loss diet. Speak with your midwife or doctor about ways to safely control your weight gain while ensuring you enjoy a healthy dietary regime.

If you’re worried about not putting on enough weight, talk to your midwife or doctor about ways to enhance your diet in a healthy way.

Underweight mums have a higher likelihood of premature or low-birth-weight babies.

How Can I Gain a Healthy Amount of Weight?

Pregnant women only need an extra 420kj per day, which is the equivalent of about two slices of bread or one egg.

Focus on the quality of your food, rather than the quantity.

Having a balanced, healthy diet is important throughout life, but during pregnancy it’s one of the best things you can do for yourself and your baby. Talk with your midwife or doctor about healthy eating and exercise during pregnancy.


Associate Professor Andrew Bisits is an obstetrician and medical co-director of the Maternity Services Division at the Royal Hospital for Women in Sydney.

Words By Andrew Bisits

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