Growth charts for the premature baby

Which growth chart should I use for my premature baby?

There are separate growth charts for premature babies. One that is commonly used is called the Fenton preterm growth chart. It’s used until the baby reaches between term (40 weeks after conception) and 50 weeks. After that, a regular growth chart can be used but the baby’s age should be adjusted to compensate for the early birth. The Fenton growth chart is available online.

A) The Fenton growth chart for premature babies

This baby boy was born at 34 weeks and 5 days. He is growing well.

A separate growth chart is used for premature babies. One example is called the Fenton preterm growth chart (Olsen 2010; Fenton 2013). This chart is used until the baby reaches between term (40 weeks) and 50 weeks after conception. From then on, the baby’s weight is followed on growth charts for term babies (those that are born at 40 weeks after conception).

The more premature a baby, the more important it is to use the Fenton chart for the early weeks.

The Fenton growth chart is available online University of Calgary and described as:

  • Girls: Fenton preterm growth chart - girls
  • Boys: Fenton preterm growth chart - boys

B) Using the term growth charts for premature babies

This baby boy was born at 34 weeks and 5 days. However, using a regular growth chart instead of one for premature babies makes his weight gain harder to assess.

If a term growth chart is used for a slightly premature baby (for example, a baby born at 37 weeks instead of 40 weeks), the baby will appear to be on a relatively low curve, even if the baby is of normal weight for its age.

This baby’s age should be corrected for the early birth. For example, at five weeks after delivery, this baby’s actual age from conception is 42 weeks (37 weeks plus 5 weeks) and its corrected age is two weeks. This correction should always be used. It becomes progressively less significant as the baby ages.

References

Fenton TR, Nasser R, Eliasziw M, et al. Validating the weight gain of preterm infants between the reference growth curve of the fetus and the term infant. BMC Pediatr. 2013 Jun 11;13:92

Olsen IE, Groveman SA, Lawson ML, et al. New intrauterine growth curves based on United States data. Pediatrics. 2010 Feb;125(2):e214-24
 
University of Calgary [Internet]. Calgary: University of Calgary; [date unknown]. Welcome To the Fenton Preterm Growth Chart webpage, 2013 Growth Chart; [date unknown] [cited 2017 Aug 29]