<prompt> Pressure created in vacuum is -12 kgs0.2 kgcm20.8 kgcm218 kgs  <response>: Ans. is c i.e., 0.8 kgcm2 When using rigid cups, it is recommended that the vacuum be created gradually by increasing the suction by 0.2 kgcm2 every 2 min until a negative pressure of 0.8 kgcm2 600 mm Hg is reached. With soft cups, negative pressure can be increased to 0.8 kgcm2 within 1 min.Differences between forceps and vacuumForcepsVacuumTraction force 18 kg for primi, 13 kg for multiNegative pressure 0.8 kgcm2 600 mm HgCervix should be fully dilatedMinimum 7 cm dilationLess fetal but more maternal complicationsMore fetal but less maternal complicationsPreferred in fetal distressLess preferred as vacuum takes time to build upRotation forceps not applied nowadaysVacuum causes rotation and extractionCan be applied on face presentation and after-coming head of breechCannot be applied on face presentation and after coming head of breechCan be applied on preterm fetusContraindicated on preterm fetus increased risk of intraventricular hemorrhageCan be applied in cases of fetal coagulopathy and if recent scalp blood sampling has been doneContraindicated in cases of fetal coagulopathy and if recent scalp blood sampling has been doneCan be applied in cases of IUFDShould not be applied as chignon formation will not occur in IUFD 