What references are you currently using to monitor fetal growth in your clinical research?
In New zealand we are currently using customised GROW charts as gold standard for assessing fetal growth from 26-28 weeks. Population based charts have been shown to miss many SGA babies. Your study uses femur lenth and head circumference as markers for growth but surely these are the last bits to stop growing, what about the AC and babies birth weight?
Is your study sugesting that we abondon assessment of fetal growth antenatally, and that as long as the population is well educated and well norished then we no nonger need to measure fundal height?
The INTERGROWTH-21st study is certainly not suggesting that you abandon the measurement of fetal growth antenatally, indeed the opposite is true.
The concept to understand is that the INTERGROWTH charts are NOT population charts, because as you say, these could miss a large proportion of abnormal babies. The INTERGROWTH study demonstrated that growth around the world is remarkably similar if conditions for pregnancy are optimal. The resulting charts are thus references that can be thought of as the 'gold standard' of growth for all babies regardless of ethnicity. This can be thought of as the closest thing to physiological growth that we know, and whilst will not be immediately achievable in all pregnancies, does give a benchmark against which all babies can be compared. The concept is exactly the same as what was demonstrated in growth in children in 2006, and the WHO growth charts are now adopted in over 130 countries.
For us obstetricians, this is a new way of thinking about growth: i.e to compare to optimal growth rather than a population or subpopulation.
Being well nourishes and educated is obviously not enough to achieve optimal growth, and we certainly are not suggesting in any way to abandon growth measurement. I am sure you well know there are a myriad of pregnancy, medical and other factors affecting growth.
INTERGROWTH-21st provides femur, HC and AC measurements, but not yet EFW. Given that all US measurements will have some degree of observer error, combining results in a formula for EFW could compound this. We are working on what measurements (or combinations) best identify the fetus at risk.
I hope this helps.
When we get to know about EFW charts....
Amongst given HC, AC, FL .. which one gives a better idea about small babies?
Traditional teaching is that AC gives better idea... reflects liver size..