Researchers at the Kaiser Permanente Southern California Department of Research & Evaluation, led by Anny H. Xiang, PhD, have concluded that gestational diabetes poses an increased risk of autism to the fetus compared to other maternal complications. This report was published in the recent issue of the Journal of American Medical Association (JAMA, April 14, 2015).
This research comes after recent studies that have revealed an increased risk of metabolic and developmental disorders in children whose mothers were affected by diabetes prior to their pregnancies or during their first diagnosis of gestational diabetes. Experimenting with increased blood-sugar levels on the neurological and behavioral development of the fetus prior to this new study, however, was previously unexplored.
Gestational diabetes affects the mother normally in the third trimester of pregnancy (from the 26th week), mostly as a result of dysfunctional insulin receptors. The main reason behind this is the elevation of human placental lactogen (HPL), which causes an aberration in the sensitivity of insulin receptors of the mother, leading to increased blood-sugar levels. Gestational diabetes affects 3 to 10% of pregnancies.
The study population of the researchers included 322,323 children of all ethnicities born between 1995-2009 at Kaiser Permanente Southern California (KPSC) hospitals. Data were recorded for these children from birth until the first date of clinical diagnosis of autism, last date of continuous KPSC health plan membership, death due to any cause, or December 31, 2012. The study showed that 7.8% of the children were exposed to risks of autism where the mothers had gestational diabetes, as compared to only 2% of those with pre-gestational, type II diabetes. The rest were unexposed to any such risk.
Other maternity related complications like smoking, weight gain during pregnancy, anti-diabetic medication and body mass index prior to pregnancy were all ruled out as factors, which could have contributed to development of autistic fetuses, strengthening the researchers’ reasoning. Factors like hypoxia (a lower-than-normal concentration of oxygen in the blood) in the fetus, oxidative stress in cord blood and placental tissue, chronic inflammation, and other genetic changes brought about by environmental factors (epigenetics) were linked to the increased risk of autism among these children.
Dr. Xiang stated that the early months of pregnancy were crucial to the mental and behavioral development of the fetus and exposure to excessive blood sugar in the early months could play a crucial role in these autistic children. Researchers believe that this is why children of mothers who had already been prescribed type II diabetic medication prior to pregnancy did not have an increased risk of autism.
“Future studies should address whether early diagnosis and treatment of gestational diabetes can reduce the risk of autism” Dr. Xiang concluded.