How Type 2 Diabetes Complicates Pregnancy
With respect to the glucose threshold that will minimize adverse perinatal outcome, studies have shown that glucose levels of pre- and postprandial and fasting blood glucose under 140 mg/dL will be sufficient to achieve rates of congenital anomalies, spontaneous abortion, and perinatal mortality comparable with those seen in nondiabetic populations.
The target glucose threshold for the prevention of macrosomia and its accompanying complications, however, is significantly lower. Studies suggest that we need to achieve mean blood glucose levels of less than 100 mg/dL to prevent macrosomia (J. Matern. Fetal Neonatal Med. 2000:9;35–41). Fortunately, we have a bit more time to impact the rates of macrosomia since this complication develops later in pregnancy, in contrast to the development of congenital anomalies so early.
We still have much to learn about the exact levels of glycemia that are necessary to reduce complications, but our current knowledge that different glucose thresholds exist for different types of complications enables us to keep patients motivated to improve glycemic control.
Even when it's not possible to achieve optimal glycemic control, any improvement should be beneficial because it will reduce the rate of complications for a given glucose threshold.
As obstetricians work together to improve care for pregnant patients with type 2 diabetes, it is also important that we develop criteria for blood glucose measurement and monitoring. Should we all measure fasting blood glucose? Postprandial blood glucose? Right now, our approaches vary. We need consistency and clear definitions if we are to compare outcomes effectively.
I always tell patients that if we work together, we will be able to improve outcomes, and I tell them never to give up. In the preconception phase, we aim for an FBG of less than 140 mg/dL, then we work on continuously lowering this level until, at around 20 weeks' gestation, we tighten glycemic control to prevent stillbirth, macrosomia, and metabolic complications.
We need to remember that diabetes in pregnancy is a chronic disease that is extremely demanding, requiring frequent blood glucose tests throughout the day, insulin injections or ingestion of oral hypoglycemic agents, frequent fetal testing, and adherence to a diet protocol. This all requires patient-physician cooperation.
Compliance in these patients should comprise all the above demands so that if a patient fails to adhere to the diabetic protocol, we can ask whether her failure to comply is based on her needs and expectations, or her physician's needs and expectations. In the end, we as obstetricians treat two patients whose needs sometimes coincide and sometimes collide. Our goal is to develop management protocols that maximize the mutual needs of both.
Source CDC
