What would you think of someone who has had three miscarriages and believes she is a loser and a failure?

My wife and I have been married a year and a half, and during that time she has experienced three unexplained miscarriages. Needless to say, these losses have been devastating to us and our relationship.
However, my wife has taken it far worse than I have. She is consumed by the notion that she is a loser and a failure. She firmly believes that anyone (particularly biological mothers) see her as nothing but a loser and a failure. I have obviously told her words to the contrary, but she never listens to me. I have long since given up trying to convince her otherwise. She, however, is determined to make me concede to her convictions, often stalking me from room to room as I try to withdraw myself from another relentless arguement, badgering me with questions about why she's such a loser, then dismissing my answers when they don't support her opinion and repeating the question over again.
I guess what I really want to know is, is there anyone out there who would support my wife's opinion that she is a loser and a failure?
Also, anyone got any advice for future arguements?