Hi Michele! I'm a fellow mom and 2nd time mom-to-be, certified fitness instructor, personal trainer and HealthyMOMs certified. From a medical perspective (re: your pregnancy and baby), there aren't any real limitations to running during regnancy. From a FITNESS perspective, I wouldn't necessarily recommmend it due to the relaxin in your joints. Running, while seemingly an easy exercise to perform, may result in many "quirks" for the unpregnant runner whose form is not impeccable, has poor quality shoes, etc. Add to that, you now have soft joints (less protection for ligaments, tendons, cartilage, etc.), added weight, change in center of gravity and so on. I am an avid runner as well but I want to run well into my old age so I have forgone running for the second time due to pregnancy because I believe that in the long run (LOL) the 10 months without is worth a lifetime of continued enjoyment for this type of exercise.
All that being said, I can understand the boredom of the limited types of cardiovascular exercise. I continue to do elliptical, stationary cycling and power-walking, all of which require you to maintain form, and keep my eye on my due date. I've also done really well with strength training in a group format for more fun and variety.
Hope this is helpful and not a downer;-) Congratulations on your pregnancy and desire to be a fit-mommy!
jeni - Mommy to Olivia Rose (9/14/02) and baby?? due 7/20/05
Healthy Moms Certfied Fitness Instructor