Lovenox before or after transfer

Hi all!! I appreciate any input from this community. In summary, i have all PGT tested embryos…I did a mock cycle (ERA) in September. Transfer in September which worked until I had a spontaneous miscarriage in October at 6 weeks. My next transfer we added lovenox to decrease miscarriage risk and this time the transfer completely failed. I’m getting ready for transfer 3 and wondering… should I avoid lovenox before transfer in case it’s messing with the implantation? Or keep it ahead to help blood flow to uterus/it seems like typically it “doesn’t hurt”