Department of Anesthesiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
Int J Womens Health. 2010 Aug 9;1:139-54. doi: 10.2147/ijwh.s4553.
The pain of childbirth is arguably the most severe pain most women will endure in their lifetimes. The pain of the early first stage of labor arises from dilation of the lower uterine segment and cervix. Pain from the late first stage and second stage of labor arises from descent of the fetus in the birth canal, resulting in distension and tearing of tissues in the vagina and perineum. An array of regional nerve blocks, systemic analgesic, and nonpharmacologic techniques are currently used for labor analgesia. Nonpharmacologic methods are commonly used, but the effectiveness of these techniques generally lacks rigorous scientific study. Continuous labor support has been shown to decrease the use of pharmacologic analgesia and shorten labor. Intradermal water injections decrease back labor pain. Neuraxial labor analgesia (most commonly epidural or combined spinal-epidural) is the most effective method of pain relief during childbirth, and the only method that provides complete analgesia without maternal or fetal sedation. Current techniques commonly combine a low dose of local anesthetic (bupivacaine or ropivacaine) with a lipid soluble opioid (fentanyl or sufentanil). Neuraxial analgesia does not increase the rate of cesarean delivery compared to systemic opioid analgesia; however, dense neuraxial analgesia may increase the risk of instrumental vaginal delivery.
分娩疼痛可以说是大多数女性一生中经历的最剧烈的疼痛。分娩早期第一阶段的疼痛源于子宫下段和宫颈的扩张。分娩后期和第二阶段的疼痛源于胎儿在产道中的下降，导致阴道和会阴组织的膨胀和撕裂。目前，有一系列区域神经阻滞、全身镇痛和非药物技术用于分娩镇痛。非药物方法通常被使用，但这些技术的有效性通常缺乏严格的科学研究。持续的分娩支持已被证明可以减少药物镇痛的使用并缩短分娩时间。皮内注水可减轻背痛。椎管内分娩镇痛（最常见的是硬膜外或腰硬联合）是分娩过程中最有效的止痛方法，也是唯一一种无需产妇或胎儿镇静即可提供完全止痛的方法。目前的技术通常将低剂量局部麻醉剂（布比卡因或罗哌卡因）与脂溶性阿片类药物（芬太尼或舒芬太尼）结合使用。与全身阿片类药物镇痛相比，椎管内镇痛并不会增加剖宫产率；然而，密集的椎管内镇痛可能会增加器械助产的风险。
