Intravenous meperidine infusion for obstetric analgesia.

OBJECTIVE

To provide safe, satisfying obstetric analgesia when epidural analgesia was unavailable.

DESIGN

Randomized, controlled study of women in labor.

SETTING

A regional hospital offering primary- and secondary-level obstetric care.

PARTICIPANTS

Thirty-nine women with low-risk, single, term pregnancies and anticipated vaginal delivery.

INTERVENTIONS

Women in the intermittent intramuscular (IM) injection group received meperidine 50-100 mg, every 2 hours, as required. Those in the intravenous (IV) infusion group received an initial bolus of meperidine 25 mg, a basal infusion rate of 60 mg/h, and intermittent boluses of 25 mg/h as required. Each participant had a maximum of 200 mg of meperidine available to her during labor.

MAIN OUTCOME MEASURE

Pain intensity was measured on a 10-cm visual analogue scale. Pain ratings were recorded when analgesia was initiated and every 30 minutes thereafter, until delivery.

RESULTS

Women who received IV meperidine reported significantly lower levels of pain (p = .0015) than women in the IM group. However, women in the IV group received significantly higher doses of meperidine (mean = 121 mg) than those in the IM group (mean = 82 mg; p = .0007). When pain scores were compared on a smaller group of participants (n = 18) who received similar doses of meperidine (100-150 mg), women in the IV group still reported lower pain scores (p = .0092). No significant differences were found between the groups in length of labor, maternal vital signs, fetal heart rate, Apgar scores, level of maternal sedation, or patient-reported side effects.

CONCLUSION

IV meperidine infusion was superior to intermittent IM injections for pain relief during labor.