2. The Control Group (n=40 women), in whom the belt was inflated with minimal pressures (from 10 to 20 mm/Hg) During Labor and Delivery To test whether differences between experimental groups are statistically significant, the sample-size should be calculated "a priori". To do this, a primary end-point has been identified: incidence of perineal-cervical lacerations. The sample-size (n > 62 subjects for two groups) will be obtained using STATA program by a two-tailed test [alpha level of 0.05 and 90% of statistical power (1-Beta)], to detect statistically significant reduction from 50% to 10% or less with respect the primary end-point. Therefore a randomized sample size of 40 pregnant women per group was chosen to allow for possible refusals or withdrawals.