Can you have two unsuccessful pregnancies and go on to have a healthy baby?

My husband and I have been trying for two years to have a baby, in which we have gotten pregnant twice. Unfortunately, neither pregnancy made it. The first pregnancy which was with a little boy we named Zane, at 19 weeks, we found out that he had a sever brain disease known as semi-lobar holoprosensephly. This means that he was born without the front part of his brain. Our doctors said that more than likely he would die within the first 30 hours of his life and that if he got the slim chance to live, he would be a vegetable for the rest of his life, completely reliant on tubes with no emotion or sense of anything. He was blind and deaf as well. We were advised to abort the pregnancy due to everything that was wrong not to mention the complications that it would cause with me. With the second pregnancy,  at 18 weeks, we went to our specialist to make sure that what happened last time, didn't happen again. We discovered that it had not, but that something else had went wrong, the baby had no heartbeat. We had went to my regular doctor's on July 2nd and everything was fine. By July 9th when we went to the specialist, he had died. We named him Sylar. When I delivered him, his cord was wrapped around his body and neck. Currently, this is the known cause of death but because of what happened previously and then this, my husband and I are going through all kinds of genetic testing. No results have been given yet. I was curious if this had happened to anyone else, mainly the holoprosenphly. There is not much information on this particular disease that I have been able to find.