Question from New Orleans, Louisiana, USA:

I am 21 years old, and was diagnosed with type 1 diabetes at the age of 16. My 25 year old fiance also has type 1 diabetes, diagnosed at the age of 2, and we are both in semi-tight control. His sugars stay around 120-140 mg/dl [6.7-7.8 mmol/L], while mine are generally higher, around 180-200 mg/dl [10-11.1 mmol/L]. About three months ago, I found out that I was a month pregnant that, due to my elevated sugar and high caffeine intake (I am in my last year of college and drink 3-4 cups a coffee a day), I had only a 50/50 chance of making it through the first trimester. So, from about a month into my pregnancy I drove myself crazy, testing sometimes over 12 times a day, taking Humalog to keep my sugars normal after meals and Ultralente for long-acting insulin. I also ate much healthier and did very low impact aerobics and walking for exercise. My sugar was the best it has been in years staying around 110-120 mg/dl [6.1-6.7 mmol/L]. I really became proud of myself and excited at the thought of having a child, but, after over a month and a half of strict control and two and a half months of pregnancy, I began having really bad cramping pains and lost the baby. My finance and I are still emotionally devastated.

My doctor feels that the miscarriage was caused by elevated blood sugars before conception and for the first month that I was unaware of my pregnancy. What is the chance of that being the reason? Can the fact that I was taking increased doses of Humalog (about 28 units throughout the day) have contributed? Could the fact that both my fiance and I have diabetes have made a difference? Could that inhibit us from conceiving again in the future? Could the excess coffee drinking combined with high sugar have contributed?