Hallow Dear,
For successful conception, three factors are essential - A healthy matured egg, healthy motile sperm and a good lining of the womb in which the fertilized egg can get implanted and grow.
You had successful fertilization. However, if there are chromosomal defects in the baby which are not compatible to continue the
pregnancy, it will abort. However, repeating the same faults suggests that the egg donor and/or sperms could be having such a fault that even after the successful fertilization, the pregnancy cannot continue. You better take opinion of Foetal medicine specialist.
Was the thickness of uterine lining (Endometrium) monitored at the time of embryo transfer? At least 10 mm thick endometrium is required for healthy
implantation. Moreover, after the implantation is successful, enough
hormonal back up, particularly Progesterone is needed. The levels of Progesterone can be measured in the blood and monitored accordingly. If there is
Progesterone deficiency, it can be reinforced by external Progesterone. At this age, it is very likely that your endometrium may not be conducive to continue the pregnancy.
At this age, I would suggest you adoption of a needy baby.
I hope this gives you some direction before you attempt your next IVF.
Dr. Nishikant Shrotri