Thanoversary 

the date on which a negative event took place in a previous year.

"the 50th thanoversary of the start of World War II"

Thanoversary by RobN January 27, 2021

transversary

The date on which an embryo was transferred to a womb.

Happy Transversary to my daughter, created by IVF and implanted on this date one year ago!

transversary by Rainbowmomma August 29, 2019