What is gestational diabetes?
Gestational diabetes mellitus (GDM) is a condition that happens when a pregnant woman – not formerly diagnosed with diabetes – develops high blood sugar levels during pregnancy. Normally, insulin, a hormone, is secreted by the pancreas to help get blood sugar inside your cells to be used as energy. However, during pregnancy, rising hormone levels that serve to help grow baby also impair the action of insulin, which means that blood sugar rises too.
Why is gestational diabetes a concern during pregnancy?
Gestational diabetes carries a number of risks for both mother and baby. For mom, there is an increased risk for preeclampsia and cesarean section. For baby, macrosomia (large birth weight), shoulder dystocia and birth injury, and low blood sugar shortly after birth may result. Babies born to moms with gestational diabetes are at a greater risk for childhood obesity, and the mother is at a greater risk for developing type 2 diabetes later in life.(4)
Despite this, moms with gestational diabetes and their babies can indeed go on to lead healthy, active, and vibrant lives. So fellow mommas, if you’re reading this and have or are concerned about gestational diabetes, please know that the future is still bright 🙂
What is the prevalence of gestational diabetes in the US?
Gestational diabetes is a fairly common pregnancy concern in the United States, estimated to affect between 4.6% and 9.2% of pregnancies. (2)
What can I do to avoid gestational diabetes?
There are some factors that increase a woman’s risk for developing gestational diabetes, including an age > 30 years, body mass index (BMI) > 25, having a first-degree relative with diabetes, and being a woman of Hispanic, African American, Native American, South or East Asian, or Pacific Island descent – and, clearly, not many of these factors can be adjusted! (4)
However, no matter a woman’s size or presence of other risk factors, eating well and exercising often prior to and during pregnancy can help a woman achieve better health during pregnancy.
Between the 1-hour glucose test (that I failed!) and my upcoming 3-hour test, I had to remind myself that even though I was doing the best that I could with eating and exercise, perhaps pregnancy could change my body in ways that I and others may not yet understand. Maybe my blood sugar regulating hormones just couldn’t keep up, maybe my body was an overachiever at pumping out other hormones that impaired insulin’s action, or maybe there was a metabolic framework or genetic code that I couldn’t control even with a healthy, balanced eating pattern! As challenging as it was, I had to give myself grace that I and some of my former choices – like the ice cream I had on my birthday and the candy I ate on a family vacation while pregnant – were not to blame or acknowledge in shame. So, I breathed. And I researched more…
Is the 1-hour glucose screening test for gestational diabetes accurate?
Turns out, the 1-hour glucose screening test is able to detect, with a 80-90% specificity, those who have gestational diabetes. (1)
But, keep in mind that the 1-hour screening test is simply that: a screening test. It is rarely used as a diagnostic test alone, especially if results are <200mg/dL. If results come back outside of normal limits, the 1-hour test is routinely coupled with a more extensive 3-hour glucose tolerance test.
In fact, one study published in 2017 demonstrated that of pregnant moms who test between 135-143 mg/dL on their 1-hour test, the positive predictive value (or the chance that they truly have the condition) for gestational diabetes is just 20%. And, of those who test between 174-199 mg/dL on their 1-hour test, their positive predictive value of having gestational diabetes is 61%. (3)
For me, it seemed as though I had around a 6 in 10 probability of being diagnosed with gestational diabetes and a 4 in 10 chance of not. Though my 1-hour glucose test came back high and a gestational diabetes diagnosis could indeed result, that 1-hour test alone was not indicative of gestational diabetes.
What blood glucose values are considered abnormal during the 3-hour oral glucose tolerance test?
Gestational diabetes is diagnosed when there are 2 or more abnormal values demonstrated during the 3-hour oral glucose tolerance test (OGTT):
Fasting ≥95 mg/dL
1-hour ≥180 mg/dL
2-hour ≥155 mg/dL
3-hr ≥140 mg/dL (1)
What can you do about a gestational diabetes diagnosis during pregnancy?
If a mom-to-be is diagnosed with gestational diabetes, a medical nutrition therapy and physical activity is considered the first-line of treatment! (4) Mom can and should work with a Registered Dietitian Nutritionist (RDN) to put a plan in place to help achieve better blood sugar balance, to gain a healthy amount of weight during pregnancy, and to make sure mom and baby get a steady supply of essential nutrients during pregnancy. Mom should also monitor her blood sugar daily to better understand if normal blood sugar is maintained or if further treatment – like insulin therapy – is needed.
The great news about all this is that research demonstrates that women with gestational diabetes who receive individualized medical nutrition therapy from a Registered Dietitian Nutritionist (RDN) works! Working with an RDN can improve control of mom’s blood sugar, and lead to reductions in the incidence of macrosomia (large birth weight babies), hypertensive disorders of pregnancy, NICU admissions, and more.(4)
What can i eat if i have gestational diabetes?
Your eating pattern may change a lot (or just a little bit!) if you have gestational diabetes. In your appointments with your RDN, you’ll be asked about all things related to food and nutrition including the foods you eat, any recent changes in appetite, where/how you eat, your access to food, how you prepare food, and your readiness to change. Your RDN will then work with you to put a plan in place for you moving forward – which will include eating a balanced amount of carbohydrates, proteins, healthy fats, and fiber. Yep, you read that right…gestational diabetes does not mean that you have to give up all carbs! In fact, many carbs deliver important components to growing a healthy baby. Your RDN will work with you to help optimize all aspects of your eating plan – including carbohydrates.