Division of Maternal-Fetal Medicine and the Department of Obstetrics and Gynecology, Beth Israel Deaconess Medical Center, and Harvard Medical School, Boston, Massachusetts.
Obstet Gynecol. 2013 Apr;121(4):798-804. doi: 10.1097/AOG.0b013e3182860b8d.
To estimate whether the timing of bladder emptying affects focal myometrial contraction development and image adequacy.
Women at 14 0/7-32 0/7 weeks of gestation undergoing a transvaginal ultrasound examination from January 1, 2012, to September 1, 2012, were eligible for this blinded randomized controlled trial. Participants were randomly assigned to undergo transvaginal imaging immediately after urination (within 5 minutes) or to defer the imaging by at least 15 minutes. The primary outcome was focal myometrial contraction development as determined by two independent blinded reviews of the images. Secondary outcomes included image adequacy and the diagnosis of placenta previa. Relative risks (RRs) and 95% confidence intervals (CIs) were calculated using repeated-measures log binomial regression.
Two hundred twenty-one women provided 335 randomized encounters for analysis. Women in the deferred scan group were 30% less likely to experience a focal myometrial contraction (28.1% compared with 40.5%, RR 0.70, 95% CI 0.52-0.93) and 41% less likely to have inadequate images (18.6% compared with 31.5%, RR 0.59, 95% CI 0.40-0.86). The two groups were equally likely to be diagnosed with placenta previa (P=.13). However, participants in the deferred scan group were 76% less likely to have images demonstrating a placenta previa and focal myometrial contraction (3.0% compared with 12.5%, RR 0.24, 95% CI 0.09-0.62) than participants in the immediate scan group. Eight women would need to defer imaging for 15 minutes from bladder voiding to prevent one focal myometrial contraction of the lower uterine segment or inadequate imaging.
A brief interval (at least 15 minutes) between voiding and transvaginal cervical evaluation is associated with decreased risk for focal myometrial contractions and improved imaging.
ClinicalTrials.gov, www.clinicaltrials.gov, NCT01513395.
I.
评估膀胱排空时间是否会影响局灶性子宫肌收缩的发展和图像质量。
2012 年 1 月 1 日至 9 月 1 日期间，14 0/7-32 0/7 周妊娠、行经阴道超声检查的女性符合本项双盲随机对照试验的纳入标准。参与者被随机分配到在排尿后（5 分钟内）立即进行经阴道成像或至少推迟 15 分钟进行成像。主要结局是由两位独立的盲法评估图像的研究者来确定局灶性子宫肌收缩的发展。次要结局包括图像质量和前置胎盘的诊断。采用重复测量对数二项式回归计算相对风险（RR）和 95%置信区间（CI）。
221 名女性提供了 335 次随机就诊进行分析。延迟扫描组发生局灶性子宫肌收缩的可能性低 30%（28.1%比 40.5%，RR 0.70，95%CI 0.52-0.93），图像质量不足的可能性低 41%（18.6%比 31.5%，RR 0.59，95%CI 0.40-0.86）。两组诊断为前置胎盘的可能性相同（P=.13）。然而，与立即扫描组相比，延迟扫描组发生下段子宫肌收缩和图像质量不足的可能性低 76%（3.0%比 12.5%，RR 0.24，95%CI 0.09-0.62）。需要有 8 名女性在排尿后至少延迟 15 分钟进行经阴道检查，才能预防 1 次下段子宫肌的局灶性收缩或图像质量不足。
在排空膀胱后进行经阴道宫颈评估前，至少间隔 15 分钟可降低局灶性子宫肌收缩的风险并改善图像质量。
ClinicalTrials.gov，www.clinicaltrials.gov，NCT01513395。
I。
