It is narrated from Umm Atiyyah (may Allah be pleased with her) that when the Messenger of Allah (peace and blessings be upon him) instructed her to wash his daughter, he (peace and blessings be upon him) also said: "Begin with her right side and with the parts washed in ablution."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 6630