Hi Shannon,
When going through FS I was advised to take Cardiprin (low dose asprin) to increase the blood supply to the endemetrium lining by having a heathy thick lining increases implantation. Heprin is a more concentrated blood thinning agent, maybe when your levels came back after a cycle it showed a slight beta and this will assist the implantation and a healthy embie. Injection sting alittle and tend to leave bruises but all worth it
Good luck