Pethidine Versus Nitrous Oxide for Pain Relief During Labor

Pethidine Versus Nitrous Oxide for Pain Relief During Labor Among Multiparous. A Randomized Controlled Trial

Systematic opioids and inhaled nitrous oxide (N2O ) are common methods for pain relief during labor. The aim of the current study is to evaluate the efficacy of systemic pethidine compared to N2O given for pain relieve in term, multiparous women in labor.

Pain relief during labor and delivery is an essential part of good obstetrical care. Labor pain and its relief have implications on the course of labor, maternal and fetal outcomes and the satisfaction with childbirth overall. Many women would like to have a choice in pain relief during labor but also would like to avoid invasive methods of pain management in labor (as epidural). Both, inhaled analgesia and parenteral opioids are common pharmacological interventions aim to relieve the pain of labor.Nitrous oxide in a 50/50 mix with oxygen is the most common concentration used for labor pain management. It is self-administered via facemask, intermittently, and has rapid onset and offset effect. Main side effects, including nausea, vomiting, dizziness and drowsiness. Pethidine is one of the most frequently used opiate agonists. It can be given intravenous or intramuscularly. Its analgesic effect starts within 10-20 minutes and lasts 2-4 hours. Reported maternal side effects include nausea, vomiting and dysphoria. Pethidine may lead to changes in fetal heart rate tracing during labor, respiratory depression, impaired sucking reflex and restlessness. Given the fact that these two routine interventions are given in different ways and have different side effects profile, the investigators aim in this randomized controlled trial to compare the analgesic effect of these two methods and their maternal and perinatal secondary effects in multiparous laboring women.

Intravenous injection of meperidine 50mg given in 100cc NaCl 0.9% over 10 minutes. Repeated doses (if needed) will be given in intervals of 2 hours minimum until a maximum of 4 doses.

Nitrous oxide in a 50/50 mix with oxygen given via self-administered face mask. The parturient will be advised to place the mask tightly on her face and to breathe through it at the first sign of forthcoming uterine contraction. Between contractions, the parturient will be advised not to breath through the mask.

Intravenous meperidine 50mg in 100cc NaCl 0.9% . Repeated doses (if needed): intervals of 2 hours minimum until a maximum of 4 doses. In cases of nausea or vomiting intravenous metoclopramide 10mg will be offered to the parturient. If pain intensity (according to visual analogue scale), 20 to 30 minutes from administration, will not decline or the parturient will ask for a different type of analgesia, inhaled nitrous oxide or epidural analgesia will be offered.

Nitrous oxide in a 50/50 mix with oxygen given via self-administered face mask. The parturient will be advised to place the mask tightly on her face and to breathe through it at the first sign of forthcoming uterine contraction. Between contractions, she will be advised not to breathe through the mask. In cases of nausea or vomiting intravenous metoclopramide 10mg will be offered to the parturient. If pain intensity (according to visual analogue scale), 20 to 30 minutes from administration, will not decline or the parturient will ask for a different type of analgesia, intravenous meperidine or epidural analgesia will be offered.

Inclusion Criteria: Multiparity (para 2 or more). Term pregnancy: 37-42 weeks of gestation. Singleton pregnancy. Vertex presentation. In labor: at least 2 contraction in ten minutes and cervical dilatation of 2 centimeters or more. Exclusion Criteria: Women who desire epidural as a first line analgesia during labor. Women receiving pethidine during the last 24 hours (prior to entering labor room). Contra-indication for vaginal delivery. Contra-indication or allergic reaction to either pethidine or nitrous oxide. History of drug abuse. Previous cesarean delivery.

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