Baby Percentile During Pregnancy Chart

A Guide to Understanding Baby Percentiles During Pregnancy

One of the most exciting parts of pregnancy is learning about the progress of your developing baby. One key measure of your baby’s progress is the baby percentile. This is a measure of the size of your baby compared to 100 similar size babies. This guide will provide you with the important information you need to understand and track the baby percentile during pregnancy.

What is a Percentile?

In statistics, a percentile is a measure of a value in relation to all other values. Percentiles are also known as centiles and are expressed as a percentage. A percentile of 50 means that 50% of babies are smaller than the baby, and 50% are larger.

What do my Baby’s Percentiles Tell me?

Monitoring the percentile of your baby during pregnancy lets you know if the baby is growing and developing as expected. Percentiles provide information about birth weight, and the length, head circumference, and abdominal circumference of your baby.

What if My Baby is Above or Below the Average?

When a baby’s percentile is lower than the average, there may be a concern about under nutrition. If it’s higher than the average, it may be a sign that the baby is over consuming calories and they may be born larger than average. If a baby is significantly lower or higher than the average, your doctor may need to perform more tests or suggest a change in nutrition and lifestyle.

Replacement Fertility Level

Baby Percentiles Chart During Pregnancy

Gestational AgeWeight (g)
24 – 29 weeks900 – 2,300g
30 – 33 weeks2,200 – 2,800g
34 – 36 weeks2,400 – 3,100
37 – 39 weeks2,800 – 3,400

The World Health Organization (WHO) also provides a detailed set of percentiles for your baby’s growth measurements that can be found here World Health Organization – Growth Standards.

How to Discuss with my Doctor?

When you are discussing your baby’s percentile with your doctor, there are a few key points you should be aware of:

  • Percentiles compare your baby to others of the same gestational age.
  • Growth charts should not be used as a diagnostic tool, but instead serve to monitor your baby’s growth pattern.
  • If your baby is at or over the 95th percentile, testing may be recommended to determine if there are any underlying medical conditions.
  • Nutrition is important, as your baby’s growth is largely influenced by the quality of your diet.

It’s also important to discuss any concerns you may have with your doctor, as they can provide information and advice tailored to your baby’s development.


Monitoring your baby’s percentile is an important part of pregnancy. By understanding what a percentile is and tracking your baby’s percentile during pregnancy, you can ensure that your baby is growing and developing as expected.

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