"The Messenger of Allaah (may Allaah raise his rank and grant him peace) would pray holding Umaamah bint Zaynab bint Rasoolillaah.   He would put her down when he prostrated, and then pick her up again when he stood up." This hadeeth was collected by al-Bukhaaree (516) and Muslim (543).  In another wording collected by al-Bukhaaree (5996)