Gestational Diabetes & Macrosomia: Understanding Your Risk During Pregnancy

Question
Hi, I am 31 years old and 32 weeks pregnant.

I passed my one hour glucose tolerance test at 28 weeks.  I am overweight by quite a bit so I don't see how this is possible.  Don't all or most overweight pregnant women have gestational diabetes?  I've never had diabetes, I just assumed since I am 45 pounds overweight that I would have it.  Also, my first baby was born by planned c-section at 39 weeks.  She was 7 lbs 14 ounces.  Does this mean if she would have been born at 40+ weeks she would have had macrosomia?

Thanks

Answer
Gestational Diabetes is seen in pregnancies where there is not enough insulin formed by the pancreas. Inculin is the hormone that regulates and controls the amount of glucose coming into your cells. If you do not have enough insulin, the glucose can enter the cells of the body (and the baby) and can cause it to grow to a very large size (macrosomia) greater than 9lbs. The fact that you are overweight does not mean that you will get gestational diabetes, as long as you are making enough insulin. That is why we check your sugar at 28 weeks. Since you passed the test, you should not worry. I do not know why you had a planned cesarean section with your first baby. Of course, if you waited another week it would have been around a pound larger, but maybe only 1/2 lb larger.