Diabetes Could Affect Fetal Brain Development

The placenta diverts blood flow away from the brain in fetuses of mothers with diabetes.

A new study found that more blood typically flows to the placenta rather than the brain of developing fetuses in mothers with diabetes. Findings from this study were presented at the European Association of Cardiovascular Imaging annual meeting.

"We know that maternal diabetes mellitus affects the fetal organs," said lead author Aparna Kulkarni, MD. "Babies born to mothers with diabetes are sometimes bigger, especially if the diabetes is uncontrolled, and the placenta is larger. There is data to suggest that some other organs such as the pancreas and the kidneys in the fetus might be affected."

Previous findings from this research team indicated there are subclinical alterations in the heart muscle of fetuses from mothers with diabetes. The current study examined whether these fetuses also had alterations in circulation.

Included in the study were 14 fetuses of mothers with type 1 or 2 diabetes, and 16 fetuses in the control group. Of the mothers with diabetes, 9 took insulin, 3 took oral drugs, and 2 used diet to manage their blood glucose levels during pregnancy, according to the study.

The investigators used fetal Doppler echocardiography to determine blood flow to the brain, heart, aorta, and placenta, and then entered this data into a computerized model of fetal circulation.

The researchers discovered that fetuses of mothers with diabetes had more blood flow to the placenta, diverting more blood from the brain compared with fetuses in the control group. Fetuses of diabetic mothers were seen to have lower placental resistance and compliance, lower blood flow to the arteries in the brain, reduced flow to the brain, and a lower cardiac output, according to the study.

“The computational model equivalent of the fetal circulation is an electrical circuit where there are resistances and compliances,” Dr Kulkarni said. “It is easier for blood to flow to the placenta, and harder for blood to flow to the brain.”

The placenta in fetuses of mothers with diabetes are known to have changes in the blood vessels that make them larger, therefore, making the organ more likely to receive additional blood supply. However, the discovery that blood flow is diverted from the brain could potentially have many implications, according to the study.

"The placenta gets taken away after a baby is born so it's no longer a part of the circulation," Dr Kulkarni said. "But it's possible that the reduced circulation to the brain in utero could affect the baby through life. We don't know enough about why this redistribution of blood flow occurs or the implications it might have. More research is needed to find out if this has any long-term impact on the health of the baby and whether anything can be done to prevent it."

Additional information regarding the underlying mechanisms of these changes, and how it may affect the child later in life could potentially change how women with diabetes are treated during pregnancy. However, until these findings are available, the investigators advise against changing current management methods.

"At the present time, I don't think any changes should be made in management of pregnant women with diabetes mellitus based on these findings,” Dr Kulkarni concluded. “Standard obstetric recommendations for strict glucose control and healthy lifestyle should be continued."