Department of Obstetrics and Gynaecology, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand.
Department of Epidemiology, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand.
J Obstet Gynaecol. 2021 Jan;41(1):77-82. doi: 10.1080/01443615.2020.1718622. Epub 2020 Mar 9.
The uterocervical angle (UCA) has recently been studied as a parameter to identify women at risk for spontaneous preterm birth (sPTB). This study aimed to investigate the distribution of UCA values by transvaginal sonography (TVS) in the second trimester of women at low risk for sPTB. TVS was performed in 450 low-risk pregnant women at gestational age (GA) 16-24weeks. The UCA distribution by GA was visualised using a scatter plot. The range of UCA values and their relationship with GA were assessed using quantile regression analysis. < .05 was considered statistically significant. A total of 242 participants with anteflexed uterus, no history of caesarean section and term delivery were analysed. The normal range of UCA (5th and 95th percentiles) was from 63.0 degrees (95% CI, 53.1-72.9) to 148.8 degrees (95% CI, 139.5-158.0) with no significant changes during this GA period (-0.3 degrees per week, = .757).Impact statement Spontaneous preterm birth (sPTB) is a major problem in obstetrics. A screening strategy using history of sPTB and cervical length (CL) measurement is the current standard to identify women at risk for sPTB and provide adequate prevention. However, a third of women who are identified as low risk go on to have sPTB, so a better means needs to be found to more reliably identify women at risk. Various studies have found that a wide uterocervical angle (UCA) was associated with sPTB, and thus the UCA has been proposed as a potential sPTB screening parameter. However, to date there is a lack of prospective studies evaluating this proposal, and no consensus about the proper gestational age to perform UCA measurements to identify women at risk of sPTB. This study reports the distribution of UCA at the GA of 16-24 weeks of low-risk singleton pregnancy women who delivered at term. The mid-90% values ranged from 63.0 degrees to 148.8 degrees with no significant differences in this GA period. Because of the wide range of UCA values at GA 16-24 weeks, more studies regarding UCA values in various gestational ages are required to fully understand the trend of UCA values along pregnancy and confirm whether or not the UCA would be a useful parameter for sPTB prediction and if so at what gestational age it would have to be assessed.
子宫颈管角度（UCA）最近被研究为识别自发性早产（sPTB）高危妇女的参数。本研究旨在探讨低危 sPTB 孕妇中经阴道超声（TVS）检查的 UCA 值分布。在孕 16-24 周时，对 450 名低危孕妇进行 TVS 检查。通过散点图直观显示 UCA 随 GA 的分布。使用分位数回归分析评估 UCA 值范围及其与 GA 的关系。P<.05 被认为具有统计学意义。总共分析了 242 名子宫前屈、无剖宫产史和足月分娩的参与者。UCA 的正常范围（第 5 和 95 百分位数）为 63.0 度（95%CI，53.1-72.9）至 148.8 度（95%CI，139.5-158.0），在此 GA 期间无明显变化（每周-0.3 度，=.757）。
自发性早产（sPTB）是产科的一个主要问题。目前，使用 sPTB 史和宫颈长度（CL）测量的筛查策略是识别 sPTB 高危妇女并提供充分预防的标准。然而，三分之一被认为低危的妇女最终会发生 sPTB，因此需要找到更好的方法来更可靠地识别高危妇女。多项研究发现，子宫颈管角度（UCA）较宽与 sPTB 相关，因此 UCA 已被提出作为 sPTB 筛查的潜在参数。然而，迄今为止，还没有前瞻性研究评估这一建议，也没有关于在适当的 GA 进行 UCA 测量以识别 sPTB 高危妇女的共识。本研究报告了在孕 16-24 周的低危单胎妊娠妇女中，UCA 的分布情况，这些妇女足月分娩。中 90%的值范围为 63.0 度至 148.8 度，在此 GA 期间无明显差异。由于 GA 16-24 周 UCA 值范围较宽，需要进行更多关于不同 GA 时 UCA 值的研究，以充分了解 UCA 值随妊娠的变化趋势，并确认 UCA 是否为预测 sPTB 的有用参数，如果是，那么应该在哪个 GA 进行评估。
