A mother accused of killing her two babies was too ill to appear at the Old Bailey.
Felicia Boots, 34, is believed to be suffering from post-natal depression.
Boots was due to appear by videolink from Holloway prison for her to be formally remanded after first appearing before magistrates. But Judge Christopher Moss was told the prison's medical centre considered she was not well enough to take part.
He said Boots is due to be transferred to a psychiatric hospital under the Mental Health Act. No bail application was made during the brief hearing and Boots was further remanded in custody to a hearing on August 10.
Judge Moss said: "I confirm that this defendant be remanded in custody with the intention that she be transferred to hospital under the Mental Health Act. That is a matter for the Secretary of State and not for this court."
Julian Evans, for the Crown, had asked for Boots to be remanded in custody. He said: "The position is that the Crown say the defendant should be remanded in custody primarily for her own safety because of her condition."
Boots was accused of murdering 10-week-old Mason and his 14-month-old sister Lily at their upmarket family home. The children were found unconscious by their father, Jeff Boots, when he returned home from work on Wednesday last week.
Emergency services were unable to revive the children. A formal cause of death has not been confirmed but the children are thought to have been suffocated.
Mrs Boots, who trained as a hairdresser, was arrested at the semi-detached home in Killarney Road, Wandsworth, south-west London. Mr Boots, an investment banker, and his wife were said to have moved to the UK in the last few years from Canada.