Diabetes in Pregnancy - 7 - Self-Monitoring of Blood Glucose Levels

After discussing the basics and importance of diet, the next step in counseling for the newly diagnosed woman with gestational diabetes mellitus (GDM) revolves around the means of assessing her ‘diabetic control’. The mainstay of management is frequent self-monitoring of blood glucose levels. The equipment (“glucometers”) currently available to perform self-testing is highly reliable, relatively inexpensive, and simple to use. Furthermore, the better units available on the market have built in memory from which can be downloaded the dates, times and values of blood sugar determinations (not that we don’t ever trust our patients with what they tell us!). It is the rare patient over the years that I have found who cannot learn, or is unwilling, to do this testing herself and in those few circumstances, there is usually a close family member (sometimes even children) who step up to help out. Self-testing actively involves the patient in her own care and allows a great deal of flexibility in diet and medical management that could (in the days of my training) only be accomplished in a hospital setting at great expense.

The patient is informed that the test is done on whole (capillary) blood obtained by fingerstick and that the glucose values we want to achieve are < 95 mg/dL on fasting values and < 120 mg/dL on values obtained two hours after meals. These correspond to venous plasma values of < 105 mg/dL and 130 mg/dL respectively. Initially, we ask the patient to obtain at least 4 blood sugar determinations each day, a fasting value and two hours after every major meal, breakfast, lunch, and supper. An example to show how this is worked into the diet routine of 3 meals and 3 snacks is as follows:

_Check fasting blood sugar within 30 minutes before breakfast; eat breakfast

_Check blood sugar two hours after breakfast; then eat snack

_Eat lunch

_Check blood sugar two hours after lunch; then eat snack

_Eat supper

_Check blood sugar two hours after supper; then eat snack before bedtime

If it possible, the patient is asked to establish a ‘routine’, trying to eat her meals and snacks and check her blood sugars on a regular time schedule each day. She is asked to record all her blood sugars on a weekly log sheet with which we provide her, recording the date, time, and blood sugar levels. This log sheet is then faxed to our office (or called to our staff) and reviewed by a physician on a weekly basis and more often if necessary. I generally will give our patients with GDM (who have never had it before) a week of diet and blood sugar determinations before deciding if medical therapy is necessary unless the levels are so high that it is clear that treatment is needed sooner. If a woman had GDM with a previous pregnancy and required medical therapy (oral agent or insulin) I will usually offer her the opportunity to resume that therapy at the time of the initial consultation since there is a very high likelihood it will be necessary again.

I think it is valuable to have the patient return to the office a week after her initial visit to review the blood sugars face-to-face, answer questions regarding her concerns and course to that point, and discuss thresholds and options for therapy, even if therapy is not yet necessary, as well as indications and methods of fetal surveillance for the rest of her pregnancy. If the blood sugar control is not adequate, we have a very low threshold for starting medical therapy and approaches to that will be the subject of our next post…

Labels: blood glucose self-monitoring, gestational diabetes

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