In this study, it was aimed to evaluate the effects of intrathecal morphine and posterior quadratus lumborum block (QLB2) on postoperative acute pain scores and opioid consumption in the first 24 hours after cesarean section.

Postoperative acute pain following a cesarean section is sharp, well-localized, and highly intense. An ideal pain management approach after a cesarean section should provide high-quality analgesia with minimal side effects and facilitate the mother's rapid return to daily activities. Different options for pain control include central blocks, peripheral blocks, and systemic medications.

Intrathecal morphine (ITM) administration is a widely used approach for post-cesarean pain management both globally and in our clinic. However, it can reduce patient satisfaction due to side effects such as nausea, vomiting, and itching. On the other hand, the Quadratus Lumborum Block (QLB), a type of peripheral block, has proven analgesic efficacy in controlling acute postoperative pain following a cesarean section. The aim of this study is to examine and compare the analgesic efficacy of intrathecal morphine (ITM) and Posterior Quadratus Lumborum in the management of acute postoperative pain after a cesarean section.

This study is a single-center, double-blind, prospective observational study.

Patients will be divided into 2 groups.

Group 1: The group receiving intrathecal morphine (ITM)

Group 2: The group receiving Posterior Quadratus Lumborum Block

In elective cesarean section cases under spinal anesthesia, the patient group receiving ITM and posterior QLB will be evaluated for obstetric general well-being during the first 24 hours and at discharge. Total morphine consumption in the first 24 hours, Pain scores (NRS) at rest and during movement, presence of nausea-vomiting and itching, patient satisfaction and any potential side effects will be recorded through follow-up.

Inclusion Criteria:

• Pregnant for at least 37 weeks
• Aged between 18 and 45
• ASA (American Society of Anesthesiologists) physical status score II
• Patient planned for elective cesarean section under spinal anesthesia
• Patient receiving QLB-II block or intrathecal morphine

Exclusion Criteria:

• ASA score of III or IV.
• Planned cesarean section under general anesthesia.
• Requirement for conversion to general anesthesia after failed spinal anesthesia.
• Contraindication to spinal anesthesia and regional anesthesia techniques.
• BMI greater than 35 kg/m².
• History of opioid use disorder or opioid use for more than 4 weeks.
• Inability to assess pain scores.
• Pregnancies of less than 37 weeks gestation.
• History of allergy to local anesthetics and systemic opioids.
• Patient refusal

Patients scheduled for cesarean section at ≥37 weeks of gestation.

The study population consisted of pregnant women who were at least 37 weeks gestational age, aged between 18 and 45 years, with an ASA (American Society of Anesthesiologists) physical status score of II, scheduled for elective cesarean section under spinal anesthesia between July 1, 2024, and October 20, 2024, and who received either a posterior quadratus lumborum block (QLB-II) or intrathecal morphine.