Fetal testing

Kay2021

I had a missed miscarriage (didn't feel a thing so had no idea whatsoever) recently, and got my D&C procedure done a few days back. They sent the fetal tissue to the lab to get it checked. Has anyone gotten it done? What could be the reason of a missed miscarriage after getting a perfect heartbeat/growth size at 8 weeks. Found out at 10 weeks that I had miscarried. Didn't bleed due to extra progesterone that I was on I think.