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Abstract：
For a dilation and evacuation (D&E) procedure, the cervix must be dilated sufficiently to allow passage of operative instruments and products of conception without injuring the uterus or cervical canal. Preoperative preparation of the cervix reduces the risk of cervical laceration and uterine perforation. The cervix may be prepared with osmotic dilators, pharmacologic agents or both. Dilapan-S™ and laminaria are the two osmotic dilators currently available in the United States. Laminaria tents, made from dehydrated seaweed, require 12-24 h to achieve maximum dilation. Dilapan-S™, made of synthetic hydrogel, achieves significant dilation within 4 h and is thus preferable for same-day procedures. A single set of one to several dilators is usually adequate for D&E before 20 weeks\' gestation. Misoprostol, a prostaglandin E1 analogue, is sometimes used instead of osmotic dilators. It is generally regarded as safe and effective; however, misoprostol achieves less dilation than overnight osmotic tents. The literature supports same-day cervical preparation with misoprostol or Dilapan-S™ up to 18 weeks\' gestation. As the evidence regarding alternative regimens increases, highly experienced D&E providers may consider same-day regimens at later gestations utilizing serial doses of misoprostol or a combination of osmotic and pharmacologic agents. Misoprostol use as an adjunct to overnight osmotic dilation is not significantly beneficial before 19 weeks\' gestation. Limited data demonstrate the safety of misoprostol before D&E in patients with a prior cesarean delivery. Mifepristone, a progesterone receptor antagonist, is also effective for cervical preparation prior to D&E, although data to support its use are limited. The Society of Family Planning recommends preoperative cervical preparation to decrease the risk of complications when performing a D&E. Since no single protocol has been found to be superior in all situations, clinical judgment is warranted when selecting a method of cervical preparation.
摘要：
对于扩张和疏散(D&E)程序,子宫颈必须充分扩张，以允许手术器械和受孕产品通过，而不会损伤子宫或子宫颈管。子宫颈的术前准备降低了宫颈裂伤和子宫穿孔的风险。宫颈可以用渗透性扩张器制备，药物或两者兼而有之。Dilapan-S™和海带是目前在美国可获得的两种渗透性扩张器。海带帐篷,由脱水海藻制成，需要12-24小时来实现最大膨胀。迪拉潘-S™,由合成水凝胶制成，在4小时内实现显著扩张，因此对于同一天程序是优选的。在妊娠20周之前，一组一到几个扩张器通常足以用于D＆E。米索前列醇,前列腺素E1类似物，有时被用来代替渗透扩张器。它通常被认为是安全和有效的;然而,米索前列醇实现比过夜渗透帐篷更少的扩张。文献支持使用米索前列醇或Dilapan-S™在妊娠18周的当天宫颈准备。随着关于替代方案的证据的增加，经验丰富的D&E提供者可能会考虑在妊娠后期使用连续剂量的米索前列醇或渗透剂和药物组合的当天治疗方案.在妊娠19周前，米索前列醇用作通宵渗透扩张的辅助药物并无明显益处。有限的数据表明，米索前列醇在D＆E之前的剖宫产患者中的安全性。米非司酮,孕激素受体拮抗剂,对于D&E之前的宫颈准备也是有效的，尽管支持其使用的数据有限。计划生育协会建议术前准备宫颈，以降低进行D＆E时并发症的风险。由于没有发现单一的协议在所有情况下都是优越的，选择宫颈准备方法时，需要临床判断。
