All too often for some the announcement of a pregnancy is also interpreted as an invitation to eat for two! But remember, that second person doesn’t need as much food as you considering they will only weigh an average of 3.5kg when born.

Too much weight gain in pregnancy puts women at risk of high blood pressure, gestational diabetes and the need for a caesarean. It also puts the baby at risk of birth defects, having a high birth weight and developing obesity and heart disease later in life.

So what’s normal weight gain?
First calculate your pre-pregnancy Body Mass Index (BMI)
Your BMI is calculated by dividing weight in kilograms by height in metres squared.

As a guide:

  • If your BMI was less than 18.5 (considered underweight), you should gain 12.5 to 18kg during your pregnancy.
  • If your BMI was 18.5 to 24.9kg (considered normal weight), you should gain 11.5 to 16kg.
  • If your BMI was 25 to 29.9kg (considered overweight), you should gain 7 to 11.5kg.
  • If your BMI was above 30 (considered obese), you should gain 5 to 9kg.

Where is the weight coming from?

At term you will be carrying about:

  • 3.5kg of baby
  • Just over 1kg of placenta
  • Just over 1kg of extra breast tissue
  • 1.8kg in extra blood (to supply bub)
  • 1.3kg in amniotic fluid
  • Up to an extra 2kg of uterus!
  • The rest is extra fat stores… which your body needs for breastfeeding.

How much or how little extra weight is gained, depends on a woman’s eating and exercise levels and to a certain extent her genes too!

The information provided is a guide only. Please consult your healthcare provider for any questions or clarifications.

Source: Dr Ginni Mansberg, Practical Parenting Magazine – Nov 2010