Naomi Izevbekhai, aged seven, and her sister Jemima, aged six, are at threat of being deported from Ireland to Nigeria, where their mother Pamela says that her busband's family is likely to force them to submit to genital mutilation.
Pamela Izevbekhai has said she left Nigeria in January 2005 due to her husband's family's practice of genital mutilation.
The High Court in Dublin is due to give a decision on her appeal on Tuesday 18 November.
Her first daughter Elizabeth died at 17 months from blood loss, which the attending doctor described as being possibly the result of female circumcision performed on the baby.
Ms Izevbekhai's in-laws are a very powerful family within Nigeria and insist on genital mutilation a "rite of passage".
Her lawyer referred to a report by Amnesty International stating there were inadequate protections against female genital mutilation in Nigeria. But official bodies in Ireland have repeatedly said that state protections in Nigeria are adequate.