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What preterm growth charts are typically used in your part of the world?


Joe

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I'm curious what preterm (or infant) growth charts are in typical use in your part of the world?

I'm a neonatologist in the U.S. and my personal observation is that local U.S. East coast practice seems to use primarily the Fenton 2013 and Olsen 2010 intrauterine growth charts as targets for extrauterine growth. (For infants and children, it's a mixture of WHO and U.S. CDC charts.)

I maintain a set of freely accessible web-based growth chart calculators (PediTools) which have been generally popular (~600,000+ page views per month) but have noticed that my primary traffic is from North America.

This leads me to wonder whether other parts of the world use different growth charts for their preterm babies, and what tools they use to determine percentiles / Z-scores? And if there aren't satisfactory tools already available, whether I should look into making available other growth charts?

Anyone care to share their thoughts?

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This is a question that has been on my mind for a long time!

I am not a neonatologist, but a clinical researcher who has worked for the last 3 decades in NICUs with preemie populations in the US.  My focus was on their ability to transition readily, or not, from tube to independent oral feeding.

As proper “growth” of the infant was an important clinical outcome, particularly when gauged as a weight gain of 15g/kg body weight/day, I have come to realize that some of these infants do not necessarily meet the above criterion despite proper nutritive sucking skills.  Due to the broad spectrum of racial/ethnic backgrounds that make up the “melting pot” of the US population, i.e., White/African-American/Hispanic/Asian-Pacific Islander/recent immigrants, I began to speculate whether parental genetics and dietary characteristics may impact on the offspring growth/development. Along this line, as a non-clinician, my concern is whether supplementing a baby’s diet to meet the 15g/kg body weight/day is a proper approach across the board.

I was told that in the 1950’s, as growth charts were based on White American babies, Asian babies regularly fell below the “normal” growth curve and were clinically of concern.

As such, I personally use the WHO data to monitor my subjects.

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As with many things in Sweden, we do it our own way* :) so we use a reference curve based on the births in the Swedish Medical Birth Register. So population-specific.

You find the publication here and the growth curves for girls and boys, here and here.

*I mean this a bit ironically, as many Swedes think about Sweden as the Center of the World. BTW, the Center of the World is Karolinska Institutet in Stockholm 😎

Skärmavbild 2022-08-19 kl. 11.00.05.png

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53 minutes ago, Stefan Johansson said:

As with many things in Sweden, we do it our own way* :) so we use a reference curve based on the births in the Swedish Medical Birth Register. So population-specific.

Very nice! Ahh, the benefits of having a proper national registry... I'm quite envious, especially with the ability to smoothly follow from extreme prematurity through 24 months on a single chart.

Do you need to use the visual chart to estimate percentiles / Z-scores of measurements, or is there a way to calculate precise numbers?

Some other growth charts use parameterization (e.g., Cole's "lambda mu sigma (LMS)" parameterization, or the INTERGROWTH-21's use of the "skew t-distribution") to allow calculations. I didn't see equations in the Swedish growth reference to facilitate those calculations.

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Thanks @Joe , but the back side of this coin is that the curve is population-specific, so less great to use in research. For example, I was just engaged in a small study where we categorized growth per Fenton Z-scores than using our own reference curve.

There should be a formula for calculating exact SD/Z-score, the graph must be drawn up from a formula. The formula for the previous curve was published, but I am not sure about this one. There are some fancy mathematical formulas in the paper (here), but nothing that can be simply added to XLS (as I understand the Appendix).

I am sure you can email to the first author Aimon Niklasson in Gothenborg (aimon.niklasson@vgregion.se) and ask about a formula.

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Re-addressing the varied growth curves  used, as a clinical researcher the protocol of 15g/kg/day instituted by a service compels caregivers to adapt new dietary intakes when a baby falls below the "curve". My concern is that it may not be appropriate for certain patients if such gain does not take into account their racial/ background. 

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(If anyone has noticed me posting and deleting things, it's because I should not try to do calculations post-call. Apologies for any confusion.)

After several mistakes on my part, this should be the correct shape of the smoothed "g/kg/day" weight gain of a male preterm infant maintaining the 50th percentile on the Fenton 2013 preterm growth charts.

Screen Shot 2022-08-22 at 4.38.37 PM.png

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We use electronic software (Badger) that calculates growth curves using WHO/UK dataset.

More importantly than the specific growth chart used is how you interpret and what you do! Of course all growth charts differ based on reference populations and none are a true standard. Growth rates in g/kg/d vary between 24-40 weeks so charting is always best. But ... what to do if growth is slow? Is there any evidence that increasing weight gain is beneficial for an individual infant?

Growth is a measure or a marker of nutritional status, not an outcome in itself. Useful for audit and research, but perhaps less useful on it's own for clinical management. Growth is one element of Nutritional status. Aim of nutrition and feeding is to improve Nutritional Status not to achieve weight gain per se. Embleton_ADC_15mins_NutrAssessment_May2021.pdfEmbleton_ADC_15mins_NutrAssessment_May2021.pdfEmbleton_ADC_15mins_NutrAssessment_May2021.pdfDOI: 10.1136/archdischild-2020-320928 

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