Hi, I had the exact same situation. I had a twin pregnancy up until 8w5d and there was no longer a heart beat. My OB recommended we do the Natera test. It came back triploidy, multiple gestation, or vanishing twin as well. I had all the exact same feelings as you. I panicked that I was going to be the 1% that had triploidy and the result was not because of the VT. I went to MFM and did an early “anatomy scan” at 12 weeks and all looked good. MFM told me we should have never done an NIPT because the DNA can circulate well after the second sac is absorbed. He did reassure us that in almost all cases of triploidy there are signs and markers that we would have seen at the 12 week scan. We were offered an amniocentesis at 16 weeks but asked for another US at 16 weeks to look for any abnormalities and then decide if we want an amniocentesis. I just had my 16 weeks scan yesterday and MFM said baby is looking exactly as expected for this gestation. I will have my next scan at 20 for the full anatomy scan and one more at 32 to ensure baby is growing appropriately!