Narrated Al-Mughirah ibn Shu'bah:
(I think that the people of Ziyad informed me that he reported on the authority of the Prophet (peace_be_upon_him): A rider should go behind the bier, and those on foot should walk behind it, in front of it, on its right and on its left keeping near it. Prayer should be offered over an abortion and forgiveness and mercy supplicated for its parents.