Gestational Diabetes: What You Need to Know

November is National Diabetes Month, an opportunity for organizations like the American Diabetes Association and the National Institutes of Health to spread awareness about the disease, share insight into risk factors and give tips for prevention. Gestational diabetes is a form of the disease that occurs during pregnancy, at around the 24th week or near the beginning of the third trimester. It typically affects between 5-6% of pregnant women, though according to a 2014 analysis by the Centers for Disease Control & Prevention, prevalence can be as high as 9.2% and even higher in certain at-risk populations.

Risk Factors

Gestational diabetes is becoming more common because of increased rates of obesity, so maintaining a healthy weight is one of the most basic ways to help lower your risk. Some ethnic groups—notably African-American, Hispanic, Native American and Pacific Islander women develop the condition at higher rates, as do women with a strong family history of Type 2 diabetes and those with a previous personal history of gestational diabetes. Poor diet and a sedentary lifestyle are also factors, however, it is important to note that a significant number of women who are diagnosed have no identifiable risk factors.

Cause

The cause or causes of gestational diabetes are not well understood, though there is a belief that hormonal effects originating in the placenta are at least partially responsible for blocking the efficacy of insulin in some pregnant women, a condition known as insulin resistance. When these hormones prevent insulin from doing its job, glucose (blood sugar) builds up to hyperglycemic levels.

Prevention and Management

What can you do to lower your risk of gestational diabetes, or to help manage it if you’ve already been diagnosed? The answers are largely the same for both questions: If you engaged in moderate exercise before pregnancy, make sure you continue to do so. Limit your intake of carbohydrates—especially simple sugars like those found in candy or soda, but which are also fairly abundant in less obvious dietary suspects like rice or pasta. Try to substitute food choices that are higher in protein and “good” fats like nuts or beans, or complex carbohydrates found in foods with a low glycemic index like vegetables, whole grains, some fruits and even some starchy items like potatoes. Foods that are high in fiber are also good.

For those already diagnosed with gestational diabetes, a low-glucose diet and exercise are also good prescriptions, but medications may be necessary as well. These can include subcutaneous insulin injections or oral anti-diabetic medicines like Glyburide and Metformin. The latter, a member of the biguanide class of antidiabetic drugs, is originally derived from Galega officinalis (French lilac), a plant used for several centuries in folk medicine, and has so far been observed to have no adverse effects on mother or child when used to treat gestational diabetes. It may even lead to better outcomes for both than treatment with insulin, though some debate continues over its use due to a lack of long-term data.

Prognosis 

Uncontrolled gestational diabetes can lead to problems with the development and delivery of your baby. Babies can be at risk for neonatal hypoglycemia, a condition at birth which can result in neurologic and cardiovascular damage. Respiratory problems can also develop.

Mothers and their babies can also both be at risk for birth trauma if gestational diabetes is poorly treated, including birth injury to infant shoulders if they are born macrosomic (significantly larger than average). Mothers carrying significantly larger babies also typically have higher rates of birth by C-Section due to the difficulty of delivering them by vaginal birth. In addition, women who have gestational diabetes have about a 50% chance of developing type 2 diabetes later in life.

Testing

Women on a standard path of prenatal care are commonly tested for gestational diabetes between 24 and 28 weeks, at the time the disease is most likely to present, and around the same time that we check for anemia. For women who’ve previously had gestational diabetes, we may screen them earlier. The test consists of drinking a sugary drink, followed by a blood test about an hour later at the lab.

Even with the increase in the incidence of gestational diabetes, women should understand that the condition is highly treatable, and that many if not most of the serious effects of the disease can be managed with diet, exercise and less commonly an ever-increasing pharmacopeia of new and better medications. A diagnosis of gestational diabetes, in the proper course of standardized care, almost always comes early enough to address with treatment and behavior modification, before complications ensue.

Erin Eppsteiner, MD is an Obstetrician Gynecologist at the Cooley Dickinson Hospital Childbirth Center. Women with questions about gestational diabetes can call the Women’s Health department at Cooley Dickinson Hospital at 413-586-9866, or the Cooley Dickinson Diabetes Center at 413-586-1601.

For more information on gestational diabetes and diabetes in general, visit www.diabetes.org or www.niddk.nih.gov.