Aslan B, et al. - Given the usefulness of single-shot spinal anesthesia (SSSA) with bupivacaine for pain control during the active phase of labor due to its simplicity and rapid onset, researchers sought to determine the efficacy of the addition of fentanyl or high-dose morphine to bupivacaine during SSSA. They randomly allocated 90 healthy consecutive multiparous parturients in the active phase of progressing labor (cervical dilatation ≥ 7 cm; pain score > 4) into 3 SSSA groups as follows: group 1 (n = 30) was provided 2.5-mg hypobaric bupivacaine alone, group 2 (n = 30) was provided a combination of 2.5-mg hypobaric bupivacaine and 10-μg fentanyl, and group 3 (n = 30) was provided a combination of 2.5-mg hypobaric bupivacaine and 0.5-mg morphine. All groups had significant decrease in the main VAS score at 3 h from baseline. Group 3 had significantly higher total analgesia duration. Outcome analyses revealed increase in the efficacy and duration of SSSA in the active phase of progressing labor in correlation with the addition of fentanyl or high-dose morphine to bupivacaine with no increase in side effects.