Newborn weight gain

newborn baby weight

Many things will influence how your baby grows, apart from how much milk they drink.

For example:


Girls are born with more fat, while boys are born longer and heavier, and boys begin by growing faster.


Genetic factors are important. If both you and your partner are taller than average, for example, your baby is likely to be taller, too.

Racial background

You or your partner’s racial background will also affect your baby’s growth. For instance, Asian babies in Britain tend to be significantly shorter than non-Asian babies by age five.

Breast or bottle

Breastfed babies grow at different rates to formula-fed babies; often they tend to put on more weight at first than formula-fed babies, but then become leaner and lighter, appearing to ‘dip’ on the charts at around four months, falling below formula-fed babies at around six to 12 months. However, what is really happening is that formula-fed babies are simply accumulating more fat at this point.

Growth charts

If you’re a parent, the ‘red book’ (your child’s Personal Health Record Book by any other name) is likely to be part and parcel of your life. The growth charts in the book will be well thumbed and marked as your baby grows. But what are they all about?

Growth charts are used to show whether your child is growing and developing as expected. The charts are based on the measurements of a number of children and are made up of lines, called centile lines. Your child’s growth is plotted along the lines.

The charts are based on measurements collected by the World Health Organisation (WHO) from healthy breast fed babies in 6 different countries and show the best growth rate for a child on a particular centile, wherever they are from and however they are fed.

The charts can also help you predict how tall your child will grow, and calculate how much body fat they have.  Growth charts:

  • are for anyone with a new born baby or child aged from 2 weeks to 4 years.
  • start measurements at 2 weeks, not birth, as most babies’ weight goes up and down at first
  • have separate measurements for premature babies
  • feature an adult height predictor to give you an idea of how tall your child will be
  • allow you to calculate your child’s body mass index (BMI), once they are over 2 years old 

Find out more from the attached Fact Sheet for Parents.