膀胱容量对经腹超声评估胎盘下缘与宫颈内口距离的影响

目的 研究膀胱容量对经腹超声观察胎盘下缘与宫颈内口距离的影响.方法 136例正常单胎妊娠孕妇,孕周18 ～27周末,于不同膀胱容量下测量同一孕妇胎盘下缘与宫颈内口的曲线距离,0～50 ml为d1组、50 ～150ml为d2组、150～ 250 ml为d3组.并根据胎盘覆盖区域的不同,将其分为前壁、后壁、侧壁三型.结果 同一孕妇不同膀胱容量下,经腹超声评估胎盘下缘与宫颈内口的距离具有差异性（P＜0.01）,且这种距离变化与胎盘覆盖位置无关（P＞0.05）.随着膀胱容量的增加,胎盘下缘与宫颈内口的距离缩短.相对于d1组,膀胱容量在d2、d3组范围时,距离变化95％单侧上界值为31.67 mm和50.70mm.结论 经腹超声观察胎盘下缘与宫颈内口距离的可信度有赖于膀胱容量,应在超声检查中引起重视.

Effects of bladder volume on transabdominal ultrasound measurement of the distance of the inferior edge of the placenta with internal cervical os

Objective To evaluate the distinction of various bladder volumes on transabdominal ultrasound measurement of the curve distance of the inferior edge of the placenta with internal cervical os. Methods 136 pregnant women by normal single births 18-27 weeks were studied. The curve distance was measured transabdominally using ultrasound in different bladder volumes, among 0-50 ml, 50-150 ml and 150-250 ml. According to the volumes, the objects were marked as dl group, d2 group and d3 group in turn. Meanwhile, depending on the placental coverage area, the subjects were divided into three kinds, the anterior, the posterior and the sidewall. Results For the same woman, there was distance variations in different bladder volumes by measurements of transabdominal uhrasound（P 〈0. 01 ） ,while distance variations was no relation to the placental coverage area（P 〉 0. 05）. With increasing bladder volume, there was an obvious trend of decreasing the distance. The 95 confidence interval for mean（ upper bound） of the distance variations was 31.67 mm and 50. 70 mm in d2 and d3 group bladder volumel, comparing the dl group. Conclusion Transabdominal ultrasound measurement of the distance of the inferior edge of the placenta with internal cervical os is dependent on bladder volume, which should be paid attention to the work of ultrasound diagnosis.