The news was conveyed by two Democratic politicians, Andi Arief and Rachland Nashidik through his Twitter account.
"Please pray for Ms. Ani's recovery. This morning, I have to go back to the NUH Singapore ICU," Arief wrote on his Twitter.
"This morning, Ms. Ani's condition in the ICU was deteriorating slightly. Please pray," Nashidik mentioned on his account.
Ani Yudhoyono had earlier been allowed to leave the National University Hospital, Singapore, after months of being in a treatment room.
Ani was undergoing treatment for blood cancer in Singapore since early February.
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