3 miscarriages, any one had this and still went on to carry successfully?

I have PCOS and ovulate about 2x's a year,literally. For this reason and 7 years of not conceiving, we have been with a fertility specialist and/or gyno fertility treatments for 3 years. We have had everything from Clomid to 3 IUI's and now 1 round of invitro and about to start a frozen egg transfer from that cycle in another month. The dilemma is, with their help, I do get pregnant. 3 times now actually. But I have also miscarried 3 times, so no baby for us so far. I know that it still can be nature taking its course, but I was just looking for others that have had similiar experiences and ended up with succes? Any help or thoughts would be greatly appreciates. Thanks in advance!