regrettable
This military action very regrettably included losses of innocent lives.
During her childhood, her father was regrettably absent.
"Regrettably, two of the patients died," the statement added.

SMART Vocabulary: related words and phrases

Good luck and bad luck
align
bad/hard/tough luck!idiom
be bad luck on someoneidiom
be down on your luckidiom
be in/out of luckidiom
blessing
fortune cookie
fortune smiles on someoneidiom
get the short end of the stickidiom
godsend
grace
merciful
mercifully
mercy
miracle
misadventure
streak
voodoo
with any luckidiom
your luck's in!idiom