How elevated does your blood sugar have to be before you’re diagnosed with gestational diabetes? Not near as elevated as we used to think, according to the findings of the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study.
A diagnosis of gestational diabetes used to be made at the point where the mother was likely to develop type 2 diabetes in the future. But according to HAPO’s recent findings, it should be defined by the point at which elevated blood sugar begins to cause problems for the baby.
Gestational diabetes is pregnancy-induced insulin resistance that results in high blood sugar levels in the pregnant mom. When it’s left untreated, that excess glucose floods across the placenta to the fetus. In response, the fetus makes extra insulin to get rid of the glucose.
Furthermore, since the fetus is getting all that extra glucose, it gets big and fat. An extra-big baby is hard to deliver safely, and the baby’s extra insulin can cause it to have low blood glucose at birth. Worse still, fat babies with extra insulin have increased risk of obesity in childhood and type 2 diabetes in adulthood.
HAPO, a seven-year international study involving 23,325 pregnant women, examined how much excess blood sugar a pregnant mom could have before her increased sugar levels began to increase the baby’s risk of problems. And the answer was – just about none. The study found that the baby’s risk increases continuously as the mother’s blood glucose level goes up, even if her glucose levels are only mildly elevated and never even reach the currently used cut-off for gestational diabetes.
The HAPO study found that as the mother’s blood glucose rose, there were associated increases in the size of the baby, the need for a Cesarean delivery, and low blood glucose and high insulin levels in the newborn.
It is likely that the level of maternal blood glucose that triggers a diagnosis of gestational diabetes will soon be lowered, but an exact cut-off could not be ascertained from the HAPO study. A new conference to do just that is in the planning stages.
Source: 67th Scientific Sessions of the ADA