A key development in the murder case of Irish nanny Aisling McCarthy Brady is anticipated later this week at a pre-trial hearing in the US.

McCarthy Brady, 35, from Lavey in Co. Cavan, is facing first degree murder charges over the death of one-year-old Rehma Sabir, who died in her care in Boston in January last year.

Two weeks ago, following an application by the Cavan woman's defence team, a Massachussetts court gave the green light to the office of the Chief Medical Officer to carry out a series of examinations on the body of baby Sabir to determine if the tot had suffered abuse prior to her death.

Defense lawyers have been pressing to gain access to the baby's remains from prosecutors for the past 18 months, arguing that evidence could be found from a post-autopsy procedure which could exonerate their client.

The latest ruling by Middlesex Superior Court allows for a defense expert to be present when the procedure takes place.

An initial autopsy, conducted last year, ruled the baby's cause of death as "blunt force head injuries", adding that it was "homicide" and "not accidental.”

However, a skeletal survey also revealed "multiple old and healing fractures" to her spine, left forearm and left leg - with some of the injuries thought to be as old as two months.

McCarthy Brady, an illegal immigrant at the time of the baby's death, is currently being detained at Framington State Prison near Boston.

Her trial is not expected to take place until October this year.

But next Wednesday a further pre-trial hearing will focus on her legal team's motion to suppress evidence in the case.