April 5, 2006
Gestational Diabetes
Question from Manchester, New Hampshire, USA:
I was diagnosed with gestational diabetes with my first and second pregnancies, around 24 weeks. I was on insulin shots by 30 weeks each time. After both of these pregnancies I was tested at my six week postpartum appointment with a two hour glucose tolerance test and received results of 155 mg/dl [8.6 mmol/L] and 170 mg/dl [9.4 mmol/L] with fasting levels around 80 mg/dl [4.4 mmol/L]. I was told I was insulin resistant and at high risk for developing type 2 diabetes. I am 26 years old, 5 feet, 4 inches and around 100 pounds when I am not pregnant. I have no trouble with blood pressure and my cholesterol is within normal limits. I was surprised that I was having such an issue with my blood sugars since I am not a typical type 2 diabetic.
This past summer, I became pregnant again and had fasting blood sugars of 120 to 140 mg/dl [6.7 to 7.8 mmol/L] and post-prandial blood sugars of 120 to 200 mg/dl [6.7 to 11.1 mmol/L] at six weeks pregnant. I began insulin shots and had a very hard time controlling my blood sugars. My A1c at five weeks pregnant was 5.1. Three weeks later, I had a miscarriage. Two weeks later, my A1c was accidentally retested and found to be 6.1. After the miscarriage, I had a two hour glucose tolerance test and the result was 169 mg/dl [9.4 mmol/L] with a fasting level of 90 mg/dl [5.0 mmol/L].
I am now pregnant again. During early pregnancy, I tested at home and found my blood sugars to be within normal range. At 10 weeks pregnant, I passed a one hour test glucose test with a result of 138 mg/dl [7.7 mmol/L]. At 16 weeks, I failed both the one hour and three hour tests. At 18 weeks pregnant, I began insulin shots and now, at 23 weeks, I am requiring as much insulin as I did at the end of my first two pregnancies. My primary care physician is concerned that I may have more going on than just gestational diabetes. He referred me to an endocrinologist, but I was denied an appointment since the endocrinologists in my area are not taking non-diabetic patients at this time. I have also has some abnormal/borderline thyroid test results. Can you offer any advice on my situation?
Answer:
At this point, I would still go with the diagnosis of gestational diabetes. The reason is that you have a history of a normal hemoglobin A1c and you started the pregnancy with normal glucose values. In addition, your body size is not typical for type 2 diabetes. Yet, you do exhibit insulin resistance with all your pregnancies and this is a predisposing factor for type 2 diabetes later in life. I would suggest repeating the thyroid studies later in the pregnancy. Due to cross reaction between some of the thyroid hormones and the hormones of pregnancy one can have the appearance of hypothyroidism. This would have to be confirmed. Ultimately, I would suggest repeat glucose testing after you deliver and perhaps on an annual basis.
OWJ
