ASD with pregnancy?

Has anyone ever experience an ASD (atrial septal defect) a.k.a. a hole in your heart while pregnant? I'm 26 weeks and my doctor just discovered I had one. I've been having really bad dizziness, shortness of breath (I can't even walk from one room to another without being out of breath) and chest pains. My doc ordered some tests and discovered I had that. My question is... has anyone else ever experienced this? I'm meeting with a cardiologist this week but have questions now. Has anyone actually went into labor with this? I just don't see how I can do it... I can't hardly breathe now with little exhertion, how's my heart going to handle going through labor? Just curious of personal experiences.