Kimberley Hainey, who was jailed for life for killing son Declan but later released, wanted to come off the heroin substitute, an inquiry at Paisley Sheriff Court heard.
But experts told her to keep taking methadone over fears that coming off it would be detrimental to Declan.
Drug worker Hazel Martin said Ms Hainey asked to come off methadone in May 2008 - a month after Declan was born. But Ms Martin and others advised against this because it takes a woman's body up to 10 weeks to return to normal.
The inquiry continues.