Slower auditory stimulation in fetuses of mothers with gestational diabetes suggests that the condition could affect fetal brain function, according to research published in the Journal of Clinical Endocrinology and Metabolism.
Gestational diabetes can have adverse effects after birth for the mother and child including macrosomia, perinatal mortality, and cesarean delivery. There is also a greater chance of the child developing type 2 diabetes or obesity later in life. Fetuses are exposed to higher glucose levels if their mothers have diabetes, which could have a direct effect on the development of the fetal central nervous system.
“This is the first time a study has shown that the mother’s gestational diabetes can affect how quickly her fetus reacts to stimuli after a meal,” said Hubert Preissl, PhD, from the University Hospital Tübingen, the German Center for Diabetes Research, and the Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, said in a press release. “The findings provide important insights into how the mother’s gestational diabetes diagnosis can affect her child’s brain activity.”
The study included 12 women with gestational diabetes and 28 pregnant women with normal glucose tolerance. After an overnight fast, the participants drank a glucose solution as part of an oral glucose tolerance test (OGTT).
The researchers measured blood sugar at 0, 60, and 120 minutes to evaluate maternal metabolism. When the mother’s blood sugar was tested, the researchers also recorded fetal auditory evoked fields with a noninvasive fetal magnetoencephalographic device to measure fetal brain activity.
The data showed that in the fetuses of women with normal glucose tolerance, the responses to sound decreased between 0 and 60 minutes from approximately 260 to 206 milliseconds, and remained stable until 120 minutes. In women with gestational diabetes, the fetuses had no change in response in the latencies during the OGTT.
The researchers performed a linear regression analysis to determine which metabolic parameters of the mother are associated with the response latency at 60 minutes. There was an independent significant correlation between the maternal blood glucose (P=.041) and maternal insulin levels (P=.037) with the response latencies of the fetuses after 60 minutes of glucose ingestion.
Latencies are considered a measurement of fetal brain functionality and maturation, and the slower responses of fetuses of women with gestational diabetes suggest that the condition directly affects brain development of the fetus and could lead to central nervous insulin resistance.
The researchers noted that insulin action in the adult brain can increase peripheral glucose metabolism through hypothalamic activation and the autonomic nervous system. It does not have the same effect on obese adults, however, which suggests insulin resistance in the brain, they wrote.
“It may be assumed that if brain insulin resistance is already induced in the fetal human brain, this may have consequences for the glucose metabolism of the offspring in later life,” the researchers concluded.