Episode Details

Episode 193: Gestational Diabetes Intro

Jesica Mendoza (OMSIII) describes the pathophysiology of gestational diabetes and the right timing and method of screening for it. Dr. Arreaza adds insight into the need for culturally-appropriate foods, such as vegetables in Mexican cuisine.    

Written by Jesica Mendoza, OMSIII, Western University of Health Sciences, College of Osteopathic Medicine of the Pacific. Editing by Hector Arreaza, MD.

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Definition

Gestational diabetes mellitus (GDM) is a condition that occurs to previously non-diabetic pregnant women, caused by glucose intolerance at around the 24th week of gestation. 

Pathophysiology

GDM arises due to an underlying pancreatic beta cell dysfunction in the mother which leads to a decrease in the amount of insulin produced and thus leads to higher blood sugar levels during pregnancy. 

The placenta of the fetus will produce hPL (human placental lactogen) to ensure a steady supply of sugars to the fetus, creating an anti-insulin effect. However, hPL readily crosses the placental barrier causing the mothers insulin requirement to increase, when the mother’s pancreas cannot increase production of insulin to that level needed to counter the effect of hPL they become diabetic, and this leads to gestational diabetes. So, basically the placenta is asking for more glucose for the baby and the mother’s pancreas struggles to keep the glucose level within normal limits in the body of the mother. If left untreated, high levels of glucose in the mother can cause glucotoxicity in the mother.

“Glucotoxicity” refers to the toxic effect of glucose. Glucose is the main fuel for cell functions, but when it is high in the bloodstream, it causes toxicity to organs. 

Prevalence of GDM.

The CDC reports mean prevenance of GDM is 6.9%. In U.S. mothers the prevenance increased from 6.0% in 2016 to 8.3% in 2021. Many different factors have played a role in increasing gestational diabetes in American mothers, some of those being the ongoing obesity epidemic with excess body weight being a known risk factor for insulin resistance. 

Another being advanced maternal age (AMA) as more American women have children later in life their body becomes less sensitive to insulin and requires a higher insulin output on top of the insulin that is required for the fetus. 

The “American diet” is also something that has a big effect in diabetes development. With the increase of high-carb foods that are readily available, the diet of Americans has declined and is affecting the metabolic health of mothers as they carry and deliver their children. 

Despite ongoing awareness of GDM, 6% to 9% of pregnant women in the United States are diagnosed with gestational diabetes, and the prevalence continues to increase worldwide. It is estimated that in 2017 18.4 million pregnancies were affected by GDM in the world, which then continued to increase to 1 in 6 births to women with GDM in 2019. 

It was also found that women living in low-income communities were disproportionately affected due to limited healthcare access. Additionally, women with GDM had a 1.4-fold increase in likelihood of undergoing a c-section, with 15% increase in risk of requiring blood transfusion. 

Screening for GDM

Gestational diabetes is screened between the 24th to 28th week of gestation in all women without known pregestational diabetes. 

In women who have high-risk for GDM the screenin