Good fertilization but no blasts

For years the husband’s infertility remained undiagnosed because he had normal semen analysis but later we found it was excessive sperm DNA fragmentation. We had miscarriages, and failed IVFs due to poor embryos for years before the actual reason was diagnosed. Once a doctor found the actual reason (which was sperm DNA fragmentation), he gave us supplements and lifestyle changes for 3-4 months before doing IVF again. Finally, healthy embryos that made day 5 blastocysts.