It may not be comfortable. And as you get further along in the pregnancy you'll probably want to go to a lower heel, because your center of gravity will be constantly changing and walking in heels will be harder to manage. Usually at about 25 weeks I recommend going to a lower heel, especially if you're having a lot of back pain.
Wearing high heels (even wide-based, clunky ones) is not a good idea during pregnancy. That's because your weight increases and your body shape and center of gravity change, making you walk differently (and less steadily). A fall during pregnancy could hurt you and possibly your baby, so think twice before adding height to your growing girth.