There is lower plasma insulin at 48 h after FGR in a well-defined (corrected for gestational age) study from Bazaes in Chile (2003 Pediatrics 111:804-9), but none of the studies from this group report plasma insulin prior to 48 h after birth. I agree that many of the studies have been restricted in sample size whilst not all have corrected for factors such as gestational eg and ethnicity when using birth size as a marker. There is one Indian study (Setia et al 2006 Pathology 38:236-8) that reports more than a 50% reduction in insulin in cord blood from IUGR defined as

Thanks Kathy. Yes it is interesting is it not. We certainly see the presentation of measured HYPERinsulinaemia in some of the IUGR infants presenting with hypoglycaemia. So looking at it the other way.....if the " usual" IUGR response is a low insulin then what is it that defines those at risk of hyperinsulinaemic hypoglycaemia?

What an interesting question. My fellow just reviewed the FGR last week but I am still relatively confusing about the role of insulin in fetal growth. Judging from different animal models it seems insulin plays different role in different species when I looked into the slide my fellow presented. I have looked into IGF1 in monochorionic twins almost 20 years ago, but not insulin levels, and was amazed that though the weights were so different their IGF1 levels were very similar. Maybe study the cord insulin levels in TTTS will provide more useful information to your question.