Neuraxial analgesia has shown to be the gold standard for effective labor pain relief, offering numerous benefits including enhanced pain control and maternal satisfaction. The methods to achieve neuraxial analgesia include lumbar epidural (LE), and combined spinal epidural (CSE). While LE may not consistently provide optimal pain relief, leading to frequent maternal requests for supplemental analgesics, CSE presents a promising advancement. This is due to the rapid onset of pain relief from intrathecal components, complemented by the longer-lasting effects of epidural medications. Intrathecal drugs have demonstrated the ability to offer more symmetrical blockades compared to epidurally administered medications. Nonetheless, some clinicians remain cautious about CSE due to the potential for increased pain when transitioning from spinal to less effective epidural analgesia. Long-acting opioids like morphine in the intrathecal space may mitigate this problem by providing transitional analgesia to the laboring parturient.
The primary aim of this randomized controlled trial is to provide evidence of whether the addition of 100 mcg of morphine in the intrathecal (spinal) component of CSE reduces the rate of breakthrough pain during labor.
Adult (≥18 years) term primiparous (≥37 weeks) patients with live singleton pregnancy
Patients who request labour analgesia and do not have any contraindications for neuraxial analgesia.
Less than or equal to 6 cm cervical dilation during the last vaginal examination.
Patients who are expected to be discharged within 24 hours of delivery.
Patients with chronic pain conditions, opioid use disorder, pre-gestational diabetes, obstructive sleep apnea, morbid obesity (BMI >40 kg/m2), or fetal abnormalities.
Patients who have intramuscular morphine within 12 hours or fentanyl >200 mcg in the preceding 4 hours.
Participants will be excluded from further analysis in case of spinal analgesic failure