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Maternal Diabetes and the Risk of Autism in Offspring: ADA

Jul 13, 2019
 
Editor: David L. Joffe, BSPharm, CDE, FACA

Author: Maya Rudolph, Florida A&M University, College of Pharmacy & Pharmaceutical Sciences, PharmD Candidate

A new study on maternal diabetes and autism examines the influence of diabetes during pregnancy and the risk of autism in children.

Maternal pre-existing type 1, type 2, or gestational diabetes diagnosed in pregnancy are linked to an increased risk of autism. Previous studies have developed the connection between maternal diabetes before and during pregnancy to the risk of autism in offspring. A study recently presented at the American Diabetes Association (ADA’s) 79th Scientific Sessions in San Francisco examined the association between maternal HbA1c levels during pregnancy and risk of autism in offspring. According to the lead speaker at the Scientific Session, children born to mothers with an HbA1c of at least 6.5% were nearly twice as likely to be diagnosed with autism within the first 4 years of life vs. children of mothers with an HbA1c less than 5.7%.

 

Autism spectrum disorders (ASD) are characterized as a group of developmental disabilities resulting in deficits in socialization, communication, and repetitive or unusual behaviors. Recently, there has been an increase in the number of cases in children in the United States. Although the mechanism of autism still remains unclear, evidence suggests factors affecting brain development may be the cause. Researchers have been focused on identifying the early life determinants for ASD risk. Maternal diabetes can be categorized as gestational diabetes, pre-existing type 1 diabetes, or pre-existing type 2 diabetes. Researchers have explained that maternal diabetes increases the uterine inflammation, oxidative stress, and hypoxia which may alter gene expression in utero. This disruption of fetal brain development can increase the risk for autism.

In the retrospective cohort study, researchers examined data records from 35,819 mother-infant pairs born in Kaiser Permanente Southern California hospitals from 2012 to 2013. The mean baseline characteristics of the pairs were as following: 51% infants born were boys; maternal age of 31 years old; pre-pregnancy BMI of 27.2 kg/m2; 51% Hispanic. Screening was conducted early in the prenatal period of all pregnancies. Median gestational age at HbA1c testing was 9 weeks and a mean HbA1c of 5.4 % during the first trimester. Researchers evaluated children until they were diagnosed with autism or till December 31, 2017. Using the Cox regression analyses, the last maternal HbA1c level in the first two trimesters estimated the hazard ratios for autism diagnosis.

A total of 84.9% of mothers had an HbA1c less than 5.7%; 11.7% had an HbA1c between 5.7% and 5.9%; 2.4% had an HbA1c between 6% and 6.5%; and 1% greater than 6.5%. There were 2% (n=707) of the children diagnosed with autism during the mean follow-up of 4.5 years. Results summed that children born to mothers with an HbA1c greater than 6.5% were nearly twice as likely to be diagnosed with autism during follow-up (HR= 1.70; 95% CI 1.06-3). The risk associated with HbA1c levels did not vary by gestational age during HbA1c testing.  (P > 0.19).

Anny Xiang, PhD, lead researcher and director of biostatistics research in the department of research and evaluation at Kaiser Permanente Southern California, stated how the first trimester seems to be critical in looking for windows of vulnerability in risk for autism. The studies found that gestational, pre-existing type 1, or pre-existing type 2 diabetes or having a high HbA1c in the first two trimesters can be associated with a higher risk of autism. The third trimester was not observed in the study. Dr. Xiang strongly  suggested for women planning to become pregnant or who are already pregnant, to make sure their blood glucose levels are monitored regularly throughout the pregnancy. In closing, Dr. Xiang also added that further studies should be focussed on researching the degree of hyperglycemia and the timing of exposure, and how it affects the severity of autism and other serious developmental disorders, such as ADHD.

Practice Pearls:

  • Maternal diabetes has led to the increased risk of poor fetal neurodevelopment outcomes, which can be a positive association to autism risk in offspring.
  • This study showed that the offspring of a mother with an HbA1c of at least 6.5% is twice as likely to be diagnosed with autism in the first 4 years of life.
  • It is critical for women who are planning to become pregnant or who are already pregnant to check blood glucose levels regularly.

 

Xu, Guifeng, et al. “Maternal Diabetes and the Risk of Autism Spectrum Disorders in the Offspring: a Systematic Review and Meta-Analysis.” Journal of Autism and Developmental Disorders, U.S. National Library of Medicine, Apr. 2014, www.ncbi.nlm.nih.gov/pmc/articles/PMC4181720/.

 

Maya Rudolph, Florida A&M University, College of Pharmacy & Pharmaceutical Sciences, PharmD Candidate