The aim of the study will be to compare the role of Dexmedetomidine, Nalbuphine and fentanyl as additives to epidural bupivacaine in painless vaginal delivery as regard of effectiveness analgesia and maternal safety.

Labor pain often causes a strong stress response. Several inhalation and parenteral anesthetics, sedatives, tranquilizers, and analgesics have been used for pain relief during labor, while over the last decade, lumbar epidural analgesia has greatly increased .

Recently, it was concerned by most mothers and doctors that how to alleviate the pain during delivery. The ideal labor analgesia should be based on maternal and child safety and should have a fast acting good analgesic effect and less adverse reaction .

Epidural anesthesia is convenient and has a less adverse reaction and obvious effect in the commonly used analgesic methods, which are widely used in the current way of analgesia .

Studies have confirmed the efficacy of dexmedetomidine in prolonging the duration of perineural nerve blocks. Specifically, perineural dexmedetomidine enhances sensory, motor, and analgesic block characteristics.

Dexmedetomidine is a selective α₂ receptor agonist and has a sympatholytic, sedative, and opioid sparing effect. It does not cause respiratory depression and can therefore be used as an adjuvant in certain clinical settings .

It has also been proved that dexmedetomidine would not increase the risk of side effects, such as nausea, headache, vomiting, shivering, and hypotension .

Nalbuphine is a synthetic agonist-antagonist opioid that has the characteristics of Mu-antagonist and Kappa-agonist activities. Nalbuphine has gained parenteral analgesia for intraoperative, postoperative, and obstetrical uses .

The analgesic potency of nalbuphine has been found to be equal to morphine, but unlike morphine, it shows a ceiling effect on respiratory depression. It has the potential to provide effective postoperative analgesia with no risk of respiratory depression .

Inclusion Criteria:

• >/= 18 years of age
• American Society of Anesthesiologists (ASA) Physical Status 2 or 3
• Full term pregnancy (>37 gestational weeks)
• Planning vaginal delivery
• Planning epidural labor analgesia
• Vertex presentation

Exclusion Criteria:

• Patient refusal to epidural analgesia,
• Contraindications of epidural analgesia (coagulopathy, local infection, vertebral deformity)
• Allergy to study agents (hypersensitivity to bupivacaine, Nalbuphine, fentanyl or dexmedetomidine)
• hemodynamic instability, severe aortic or mitral stenosis)
• Severe pre-eclampsia,
• Breech presentations
• Antepartum hemorrhage
• Cephalopelvic disproportion
• Body mass index ≥40 kg/m2.
• Uncontrolled systemic comorbidities [i.e., diabetes, hepatic, renal or cardiac]
• Known or suspected fetal abnormalities
• Inability to communicate or participate in study procedures