The murder charge against Co Cavan nanny Aisling Brady McCarthy, who had been accused of murdering a one-year-old baby in her care, has been dropped.

It comes after the medical examiner’s office reversed an earlier statement and concluded that the death was not a homicide.

The examiner ruled, "while I do not agree with all of the conclusions that are drawn by the various experts they do present a significant amount of additional information that was not available to me prior to reaching my original conclusion about the cause and manner of death in this case."

The child's manner of death has now been classified as "undetermined".

In particular the overall state of one-year-old baby Rehma Sabir's health and her past medical issues raised the possibility that she had some type of disorder that was not able to be completely diagnosed prior to her death.

District Attorney Marian Ryan said "based on an assessment of the present state of the evidence, including the amended ruling from the Medical Examiner who performed the autopsy, the Commonwealth cannot meet its burden of proof.”

Aisling Brady McCarthy (37) was facing a first degree murder charge and has already spent almost two-and-a-half years in jail before being freed on bail earlier this year.

The nanny was arrested in January 2013, five days after Rehma Sabir was pronounced dead at Boston Children’s Hospital. 

Defence lawyers claimed prosecutors did not have enough evidence to charge Ms McCarthy, and accused them of presenting "false and deceptive" information to a grand jury.

She pleaded not guilty and was granted provisional release on bail and ordered to wear a GPS monitor in May of this year.