Multiple studies showed the numerous advantages of implementing programmed epidural bolus (PIEB) technique, where a fixed volume of local anesthetic is automatically administrated at a set time interval compared to the continuous epidural infusion technique (CEI). The advantages were improved maternal satisfaction, decreased local anesthetic consumption, and decreased second stage of labor.The theory behind PIEB is that to attain a more uniform spread of local anesthetic in the epidural space a higher volume of injectate and a higher pressure is needed.Different approaches using different timings and volumes for PIEB have been proposed to achieve the optimal regimen. Many studies showed evidence that 10 mL boluses of bupivacaine 0.0625% with fentanyl 2 μg/mL delivered every 40 min, named effective programed intermittent epidural bolus interval 90 (EI90), produced effective analgesia without breakthrough pain in 90% of nulliparous women during the first stage of labor.

Inclusion Criteria:

• Patients of ASA physical status 2-3 with a singleton pregnancy
• gestational age > 37 weeks
• regular uterine contractions occurring at least every 5 min;
• cervical dilation 2-5 cm
• pain > 5 (Visual analogue score (VAS) 0-10) at the time of request for epidural analgesia .

Exclusion Criteria:

• Refusal to concent
• Contraindication to epidural analgesia as allergy or hypersensitivity to bupivacaine or fentanyl
• Patients who had opioids or sedatives within 4 h preceding epidural insertion.
• Unintentional dural puncture.
• Patient who deliver within 1 h after initiation of epidural clinician bolus.
• The inability to achieve as VAS score ≤2 after the initial loading dose will be considered as a failure and will be excluded from the study.

Nulliparous and multiparous women