I had my j-pouch for 3 1/2 years before going to a perm ileo. Had the pouch removed 18 months later. At age 34, we pursued IVF. In MA treatment is covered by insurance, but you must do 6 rounds of IUI first. Due to my situation and the fact that the IVF drs did not believe IUI would work for me and they did not want me to carry more than 2 (and avoiding high order multiples is much harder with IUI) we got approval to skip 4 of those cycles.
First IVF cycle we transferred 2 3 day 8 cell embryos. We believe I was pregnant with twins initially, but at 8 weeks only one survived - now my 10 year old son. We had 3 frozen embryos and did a frozen transfer about 20 months later. I did get pregnant but it was shaky from the start. I miscarried at 8 weeks. Second fresh cycle I had OHSS and because of the miscarriage we decided to do a 5 day blast transfer - just one. The OHSS was still not great on day 5 so we waited an extra day. So we transferred a 6 day hatching embryo - now my 8 year old daughter.
For me, it appears that egg meeting sperm was the issue, and once that was addressed, the embryos implanted with no problem and I was able to carry full term (with the one miscarriage in between).