Fetal Hyperinsulinaemia and Epigenetic Change:The risk of lasting health effects from diabetes in pregnancy

I’ve mentioned a few times now how one of the principal risks of diabetes to the developing fetus is macrosomia  which in turn is mainly a problem for delivery. In truth, however, this is a simplification of the situation – a situation about which thought is rapidly evolving in line with the emerging area of developmental biology known as epigenetics.

I’ve touched on epigenetics before. Essentially it’s the study of changes in the way that genes are expressed which are caused by factors other than changes in the structure of the DNA itself. Amongst these factors are environmental conditions to which we exposed throughout our lives, and as far back as during fetal development. Epigenetics looks at how what we do during our lives may affect our genes and therefore our offspring, which is in direct contrast to the long held beliefs surrounding genetic inheritance that essentially suggested that no matter what choices you made in your lifetime, your genes would remain unaltered and so your children unaffected.

The specific environmental factor which is unique to babies born to mothers with diabetes is hyperinsulinaemia – production of a high level of endogenous insulin in response to hyperglycaemia caused by glucose crossing the placenta from the mother. There appears to be some evidence emerging that hyperinsulinaemia may be the factor which connects maternal diabetes to an increased risk of obesity in later life. An interesting article in far more depth can be found here.

Or, to cut a long and complex story short, failing to maintain normal blood glucose levels during pregnancy may lead to genetic changes for our children which alter their metabolism and predispose them to obesity, and all its potential sequelae, later in life.

I’ve not really written about this up until now, partly because it’s still an new area of investigation and scientific understanding is still rapidly evolving. But also, it doesn’t make easy thinking for a pregnant type 1 diabetic. There are enough well established risks to think about such as macrosomia and increased risk of stillbirth or birth defects. There is a lot of focus on getting the pregnancy safely concluded and a healthy baby delivered. You know by now that I’m doing my absolute utmost to minimise these risks and reach that goal.

When I start to think beyond that, about whether my health conditions and the things that I am able to achieve during pregnancy might have a more far reaching effect in terms of lasting heath risks, it becomes overwhelming. I’ve pushed aside the thought that our child may already have a slightly increased risk of developing diabetes. If I start to dwell on the fact that I may cause them to face life long metabolic disruption – to start three steps behind in the race to avoid obesity – then it goes beyond motivating and becomes just plain scary. I know these risks are very present, but the path to minimising them is the same as the path to minimising the more immediate effects.

I have to keep on keeping on. Because the baby’s birth won’t be the end of the story. I don’t just want a healthy baby, I want a healthy child who will grow in to a healthy adult capable of having healthy children of their own. Helping them to do that starts now.


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