Katie,
I am a diagnosed Celiac, so any questions, concerns etc. - ask away! I have been Gluten Free for over 3 years and have learned to navigate around a lot. Warning: LONG POST! I would research your GI am make sure they are familiar with Celiac. There are a lot of myths in the medical world involving it and sometimes hard to find a Dr. that is up to date.
1) There are very, very few false positives on the blood test. Most GI's will tell you the small bowel biopsy is the gold standard, BUT most people will tell you that if you have a positive blood test and have positive dietary response, that is also a Gold standard. Biopsies are hit or miss - if the lab doesn't know what they are looking for or the GI happens to biopsy an area that is not blunted, OR you go gluten free prior to the biopsy and start to heal, then you will get a negative biopsy result. And Missed Diagnosis.
2) If you feel it is important to have the biopsy, then you must continue to eat gluten - daily. It sux.
3) Generally, it is believed that undiagnosed Celiac causes miscarriages because of malabsorption. Once your intestines start to heal and you start absorbing nutrients again, your risk of m/c is only slightly elevated. Complete healing can take 6-24 months, depending on the extent of the damage. I had no villi left in the small intestine (My stupid GI that missed it told me I had the smoothest small intestine he had ever seen). It took me the full 2 years to heal. In the meantime, switch to sublingual vitamins (dissolve under the tongue) - it will get you the nutrients you need and help you heal.
The diet can be overwhelming at first. It is a lot to take in, but you get accustomed to it and you learn to plan ahead - especially when traveling or visiting people or attending parties. It is much easier than it was 3 years ago because now wheat is required by law on the food labels in the US (Barley and Rye are not, but they are not as common). You can still have Italian food - There are gluten free pastas and depending on where you live - gluten free resturants and even GF pizza places.
I have a ton more info and recipes, but I will start with this for now.
Kat.