Consecutive measurement of cervical length during uncomplicated pregnancy through transvaginal ultrasound / 中华围产医学杂志

ABSTRACT

ObjectiveTo investigate the change of cervical length (CL) during uncomplicated pregnancy by transvaginal ultrasound and its correlated factors.MethodsData of five hundred and ninety-five normal singleton pregnant women who received vaginal ultrasound examination on CL in their 11-13+6gestational weeks ( Ⅰstage),20-24 gestational weeks ( Ⅱ stage),28-32 gestational weeks (Ⅲ stage) and ≥36 gestational weeks (Ⅳ stage) were collected and retrospectively analyzed.Related factors were recorded at the same time.Repeated measurement data analysis of variance,t-test and Spearman correlation analysis were applied for statistical analysis.Results(1) The mean values of CL at Ⅰ,Ⅱ,Ⅲ and Ⅳ stage were (38.85±3.11) mm,(38.92±4.10) mm,(36.43±4.69) mm and (30.63±6.11) mm,respectively.There were statistical differences between the CL of any two stages (P＜0.01),except for that between Ⅰ and Ⅱ stage.The median values of CL change rates wereⅡ-Ⅰ stage0.00％; Ⅲ-Ⅰ stage -5.36％; Ⅳ-Ⅰ stage -20.00％.(2) The CL of pregnant women who were older than 35 was longer than that of those younger than 35 at any stage [ Ⅰ stage(39.36±3.18) mm　vs (38.77±3.10) mm;Ⅱ stage(39.89±4.61) mm vs (38.88±4.00) mm;Ⅲ stage(37.29±4.79) mm vs (36.31 ±4.67) mm;Ⅳ stage(32.25± 5.95) mm vs (30.38±6.10) mm],while significant difference was found only at Ⅳ stage (t=-2.56,P=0.01).The CL of multiparas was longer than that of primiparas [ Ⅰ stage(38.95±2.59) mm vs (38.76±3.14) mm;Ⅱ stage(39.54±3.62) mm vs (38.82±4.11) mm;Ⅲ stage(37.37±4.21) mm vs (36.34±4.70) mm;Ⅳ stage(31.77±6.05) mm vs (30.59±6.11) mm],while there was no statistical significance within any stage ( P＞ 0.05). ConclusionsCervix shortens gradually after 28 gestational weeks.Sequential measurement of CL during routine ultrasonic inspection might be helpful in predicting preterm labor.