Earlier it was recommended that transferring multiple embryos improves the chances of fertility since knowing which embryo was viable was hard to determine.
This sometimes led to multiple births. However, new advances like extended blastocyst culture and PGS/CCS have created this less necessary.
Due to the potential health risks associated with multiple births, most fertility specialists don’t suggest implanting more than one embryo at a time unless indicated.
Instead, viable embryos are often frozen and kept safe for future use.
It's always recommended to take a second opinion with the experts.