The case of the toddler, who by law cannot be named, has caused outrage in the country. Campaigners have given her the name "Victoria".
Police say the attack took place on 16 May. A school employee is under arrest and charged with raping her.
But DNA evidence has been inconclusive and nursery staff dispute it was him.
He has yet to give evidence in court or enter a plea, the lawyer defending him told the BBC Burmese service.