IRCT20201219049769N1 IRCT 2021-01-03 Islamic Azad University Evaluation of the effects of Entonox and local anesthesia in painless delivery Comparison of the effects of ENTONOX inhalation and regional anesthesia on labor pain reduction in vaginal delivery 2020-01-23 anticipated 60 Complete https://irct.ir/trial/53144 interventional Randomization: Not randomized, Blinding: Not blinded, Placebo: Not used, Assignment: Parallel, Purpose: Supportive. 3 Painless delivery. Intervention 1: Intervention group 1: Patients in this group were instructed to apply the Entonox mask firmly on the face and breathe in it as soon as uterine contractions begin, and continue to do so until the end of uterine contractions, leaving the uterine contractions in between. This continues from 5 to 4 cm dilatation of the cervix to complete dilatation. Entonox gas is a mixture of 50% oxygen + 50% N2O. Intervention group 2: Patients in this group will be injected with 25 micrograms of fentanyl with needle number 27 for local anesthesia in the L3-L4 or L4-L5 area. Intervention 2: Intervention group 2: Patients in this group will be injected with 25 micrograms of fentanyl with needle number 27 for local anesthesia in the L3-L4 or L4-L5 area. Intervention 3: Control group: In this group,no anesthetic will be used and patients will give birth naturally. Undecided - It is not yet known if there will be a plan to make this available Justification or reason for indecision in sharing IPD is There is no further information