A randomized, single blind, controlled, prospective study was performed. Subjects were nulliparous women who delivered at a community setting hospital (U.O.C. Obstetrics and Gynecology, "San Giuseppe" Hospital, Empoli, Italy) between January 24, 2011 and March 24, 2011. Vaginal deliveries were eligible. Patients were therefore divided into two groups by randomly numbered envelopes upon full dilatation of the cervix, and allocated to the following two groups: