YG Entertainment has released official statements about why Ahjeon will not debut with BABYMONSTER.
"Ahjeon, who was preparing to debut with BABYMONSTER, has decided to focus on her health and rest for the time being due to health reasons. This decision was made following careful discussion.
We are sorry that we could not introduce Ahyeon as a member of BABYMONSTER, but this decision was made in consideration of the health of the artist. We will spare no support so that Ahyeon can fully recover and return in good health."
— YG Entertainment