Premature babies
Most health professionals monitoring the growth and development of newborn babies will use special growth charts. These may be part of the child's personal health record, or kept as a file at the clinic. The charts are used to plot your baby's changing weight, length (or height), and head circumference, and are often referred to as 'percentile charts'. Percentile charts aim to give you a visual indication about how your baby is progressing over time, as well as illustrating the wide range of measurements that can be 'normal'. They identify normal variations of the baby's 'vital statistics' by graphing them into a percentage order, depending on where they fall in relation to the rest of the population average, for either girls or boys.
The percentile graphs are marked with curved lines that represent the different percentiles. The main percentile bands are the 10th, 50th and 90th percentiles, but they may also have the 5th, 25th, 75th and 95th percentiles. To gain an understanding of the percentage order system, an example is:
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If your baby is on the '10th percentile' for weight, it means that 90% of other babies their age are heavier than he or she is, and 10% of other babies weigh less. Or |
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If your baby is on the 95th percentile, only 5% of other babies of the same age are heavier than your baby, and 95% weigh less. |
Both of these measurements, even though they are at different ends of the charts, are still within the normal range. The vast majority of babies tend to fall somewhere between the 5th and 95th percentile for weight, length and head circumference. The 'average' baby will be on (or close to) the '50th percentile' line.
Image 12-01 illustrates the various percentile lines on a weight chart for baby boys.
Premature babies. If your baby was born premature, their growth rate will be different to that of a full