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What is GDM?

What is GDM?

GDM stands for gestational diabetes mellitus.  It affects around 9% of pregnancies in the US and up to 15% globally.  It is one of the most common pregnancy complications.  During pregnancy, it’s common for your body to have an imbalance in insulin release or your body’s response to insulin.  This results in higher blood sugars leading to gestational diabetes.  GDM can have a range of pregnancy complications including a baby’s that larger than normal, preterm birth, and preeclampsia – a condition where your high blood pressure becomes too high and causes even more complications.  Having a baby that’s too large can result in significant shoulder injuries to the baby during delivery, more bleeding during vaginal delivery, and a higher risk of needing a C-section.

Long-term complications of GDM?

As the name implies, gestational diabetes is diabetes that occurs only in pregnancy.  However, about 50% of women who develop GDM go on to develop type 2 diabetes.  Women with GDM also have a higher risk of post-partum depression, metabolic diseases, and cardiovascular disease.  GDM has also been associated with a higher rate of cancers later in life, such as ovarian, endometrial, and breast cancer.

For the infant, having a mother with GDM has a higher risk of diabetes, obesity, and neurologic or psychiatric diseases.

What are the risk factors for GDM?

Studies indicate that being overweight, having had a prior pregnancy with GDM, pre-diabetes, having an immediate family member with diabetes, polycystic ovarian syndrome, and having a prior baby over 9 pounds may increase your risk of GDM.  However, studies have shown that a significant number of women who develop GDM have no risk factors.

How is GDM diagnosed and what are the limitations?

The diagnosis happens in the late 2nd trimester around 24-28 weeks of pregnancy.  Currently, the “gold standard” test is something called an oral glucose challenge test.  This test involves going to a doctor’s office and drinking a sugary drink.  Either a nurse or lab technician will measure your blood sugar levels in response to the sugary drink.  Too high a number indicates gestational diabetes.

While this is a well-vetted test, the current way GDM is diagnosed is fairly late in the pregnancy.  Furthermore, you can only be diagnosed with gestational diabetes after the disease has occurred.  There are currently no accepted tests to better identify patients who are at higher risk of developing GDM and avoid it altogether.

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