Gestational diabetes (GD) is the term used to describe diabetes that develops during pregnancy, and it's a big problem, as Rick and I discuss on PodMed this week. According to these new recommendations from the United States Preventive Services Task Force, or USPSTF, published in Annals of Internal Medicine, about 240,000 pregnant women are affected by gestational diabetes each year in the United States, or about 7% of all births. Okay, so what's the harm in a little elevated blood sugar during pregnancy? Turns out that preeclampsia, macrosomia and consequent difficulties during delivery, and low blood sugar in the infant all occur much more frequently in women with GD. Longer term risks are also present; our former colleague and diabetes expert Christopher Saudek, here at Johns Hopkins, was fond of identifying GD as "diabetes unmasked," referring to the probability that a woman who developed GD was much more likely to manifest frank diabetes later in life. Indeed, the USPSTF places that probability at 15 to 60% within five to fifteen years of delivery. And of course we are well aware of the many negative health consequences of long term diabetes.
As is their wont, the USPSTF took a look at all of the literature relative to GD, crunched the numbers and came up with these modified recommendations, which haven't been updated since 2008. All pregnant women are now recommended to undergo screening for the condition after 24 weeks of gestation. This does not apply to women previously diagnosed with either type 1 or type 2 diabetes. The panel concluded that there is insufficient evidence to recommend screening before 24 weeks, and that the risk of harm to mother or fetus from screening is minimal.
The type of screening recommended is the oral glucose challenge test, to which I respond, yuck! Women are not required to fast prior to consuming 50g of glucose in a very sugary drink. Blood is taken at 1 hour following consumption and plasma glucose levels measured. If this generally exceeds 130mg/dL a second test is advised where a bit more glucose is consumed and more than one assessment of plasma glucose made, the so-called oral glucose tolerance test. The diagnosis of gestational diabetes is made when 2 or more of these values fall above the threshold.
What then? First recommendations, as for almost anyone with a new diagnosis of diabetes, involve diet and lifestyle, including increased moderate exercise. Diabetes educators and nutritionists should be brought in and monitoring of blood glucose employed. If these interventions prove inadequate then medications may be added. Clearly the fetus must be monitored and delivery plans considered if fetal growth is accelerated. And finally, women who develop GD should be educated that they've received a red flag with regard to their risk for developing frank diabetes and should consider interventions such as weight loss and increased exercise as well as dietary modifications to avoid this or at least stave it off as long as possible.
Other topics this week include a new medication for genital herpes simplex in NEJM, and two from the BMJ: a small risk for pulmonary hypertension in the infant for women who take SSRIs in late pregnancy, and endovascular versus open repair for ruptured abdominal aortic aneurysm. Until next week, y'all live well.