Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA.
Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA.
Am J Obstet Gynecol MFM. 2024 May;6(5S):101303. doi: 10.1016/j.ajogmf.2024.101303. Epub 2024 Feb 2.
An accurate transvaginal ultrasound cervical length is paramount to obtain the best prediction for preterm birth. Transvaginal ultrasound cervical length should be optimally obtained when a lower uterine segment contraction is not seen. For universal transvaginal ultrasound cervical length screening at approximately 20 weeks of gestation, the options are to do the transvaginal ultrasound soon after bladder void (lower uterine segment contractions present in 16%-43% of this approach) or to wait until the end of the anatomy scan (ideally within 30 minutes after bladder voiding) to decrease the chance of a lower uterine segment contraction. If the lower uterine segment contraction persists even after waiting up to 20 minutes or more, only the true transvaginal ultrasound cervical length should be reported. In particular, in patients with a previous spontaneous preterm birth, if the lower uterine segment contraction persists, the transvaginal ultrasound cervical length can be repeated in ≤7 days even in the presence of a normal (>25 mm) cervical length. Similar to a blood pressure cuff that must be of the right size for proper blood pressure measurement and a glucometer that must be properly calibrated, screening with transvaginal ultrasound cervical length should only be performed following a proper and standardized technique, including avoiding as much as feasible the presence of lower uterine segment contractions.
经阴道超声测量宫颈长度对于预测早产至关重要。只有在未观察到子宫下段收缩时，才能获得经阴道超声测量宫颈长度的最佳结果。对于在大约 20 周妊娠时进行通用的经阴道超声宫颈长度筛查，可以选择在排空膀胱后立即进行经阴道超声检查（这种方法中有 16%-43%会出现子宫下段收缩），或者等到解剖扫描结束时进行（理想情况下在排空膀胱后 30 分钟内），以减少子宫下段收缩的机会。如果即使等待 20 分钟或更长时间后子宫下段收缩仍然存在，仅应报告真正的经阴道超声宫颈长度。特别是对于有自发性早产史的患者，如果子宫下段收缩持续存在，即使宫颈长度正常（>25 毫米），也可以在≤7 天内重复进行经阴道超声宫颈长度检查。就像血压计必须大小合适才能进行正确的血压测量，血糖仪必须经过适当校准一样，经阴道超声宫颈长度筛查也只能在正确和标准化的技术之后进行，包括尽可能避免子宫下段收缩的存在。
