Prediction of abortion interval and misoprostol dose using strain elastography in mid-trimester abortions. Cross sectional study

This data were collected prospectively from April 2025 to September 2025. Informed consent was obtained from all patients before evaluation. Patients were selected among pregnant women whose pregnancies will be terminated due to fetal and/or maternal factors. Between the maternal age of 18-50, second trimester (12-24 weeks), presence of board and family approval were determined as study inclusion criteria. Patients with a history of cervical surgery, presence of connective tissue disorder, gestational weeks rather than mid-trimester, presence of preterm labor symptoms, cervical dilatation during examination, patients with incomplete data, lack of patient compliance for transvaginal ultrasound (US), and patients who did not want to participate in the study were excluded. Demographic and clinical data, including age, gravida, parity, weight (kg) and height (cm), were collected through a questionnaire. Body mass index (BMI) was calculated (kg/m2). Patients’ groups related with previous delivery types were recorded as; prior cesarean delivery (without any vaginal delivery), nulliparous and vaginal delivery (with or without cesarean). Fetal termination causes were grouped as; fetal anomaly, fetal death, rupture of membranes (RM). Following US and elastographic measurements, misoprostol protocol was initiated. Following the administration of both sublingual and vaginal 200 µg misoprostol, a 200 µg sublingual misoprostol was continued every 3 hours until abortion process was completed. Our clinic is a tertiary referral center, and due to the high number of complicated obstetric patients, a relatively low-dose misoprostol protocol was applied to avoid increasing complications. A total of 67 patients were included the study. No patient was included in more than one group that was described previously. When the termination process was completed; total misoprostol doses, abortus time intervals (minute), fetal weight (gram) data were recorded.Elastography method:SE technique was defined and figures were added to ensure reproducibility. The strain measurements are displayed on a semi-transparent colored map called an elastogram, which is overlaid on the B-mode image (Fig. 1). Typically, low strain (stiff tissue) is displayed in blue, and high strain (soft tissue) is shown in red, although the color scale can vary, depending on the US vendor. SR, a pseudo-quantitative measurement, compares stiffness of different tissues as a target and a reference tissue. SR >1 shows the target lesion compresses less than the reference tissue, indicating lower strain and greater stiffness (Choi et al. 2015). With this information, 1 hour before the intervention each patient’s cervix and uterus were examined in the midsagittal plane using the transvaginal B-mode US. Cervical length (CL) was measured internal cervical os to external cervical os in midsagittal plane. Fetal biometry was recorded as biparietal diameter (BPD), abdominal circumference (AC), femur length (FL) and estimated fetal weight (EFW). With the elastography mode of US, the reference (anterior lip of external cervical os) and target (anterior lip of internal cervical os) region of interest (ROI) were determined, and compression and decompression cycles were applied with the transvaginal probe manually. SR was calculated at the peak of the pressure in the area where the trace was regular. SRs were calculated at least three times, and the mean SR was saved. All US examinations were performed by a single gynecologist with Voluson S8 (GE Healthcare, Chicago, IL, USA, equipped with a 4.0–9.0 MHz multifrequency transvaginal probe).

本数据集于2025年4月至2025年9月前瞻性收集。所有受试者在评估前均已签署知情同意书。研究对象选自因胎儿或母体因素需终止妊娠的孕妇，纳入标准为：年龄18~50岁、妊娠处于中期（12~24周）、经伦理委员会及家属批准。排除标准包括：有宫颈手术史者、结缔组织疾病患者、妊娠周期非中期者、存在早产症状者、检查时宫颈扩张者、数据不全者、无法配合经阴道超声（ultrasound, US）检查者以及拒绝参与本研究者。通过问卷收集人口学与临床数据，包括年龄、孕次、产次、体重（kg）与身高（cm），并计算体重指数（body mass index, BMI，单位kg/m²）。根据既往分娩方式将受试者分为三组：既往剖宫产（无阴道分娩史）、未产妇、经阴道分娩（有或无剖宫产史）。终止妊娠的原因分为胎儿畸形、胎儿死亡、胎膜早破（rupture of membranes, RM）三类。完成超声及弹性成像检测后，启动米索前列醇给药方案：先予舌下及阴道途径各200μg米索前列醇，之后每3小时予舌下200μg米索前列醇，直至流产完成。本中心为三级转诊医院，因复杂产科患者较多，故采用相对低剂量的米索前列醇方案以降低并发症风险。本研究共纳入67例受试者，无重复分组情况。当流产过程完成后，记录总米索前列醇剂量、流产时间间隔（分钟）、胎儿体重（g）。弹性成像方法：本研究采用剪切波弹性成像（shear wave elastography, SE）技术，附有多幅示意图以保证结果可重复性。应变测量结果以半透明彩色映射图（弹性图）形式呈现，叠加于B型超声图像之上（图1）。通常低应变（组织僵硬）以蓝色显示，高应变（软组织）以红色显示，但色标可因超声设备厂商不同而有所差异。应变比（strain ratio, SR）为半定量测量指标，以目标组织与参考组织的硬度对比为基础：当SR>1时，提示目标组织的压缩程度小于参考组织，即应变更低、硬度更高（Choi等，2015）。干预前1小时，所有受试者均行经阴道B型超声正中矢状面检查。测量宫颈长度（cervical length, CL）：于正中矢状面测量宫颈内口至外口的距离。记录胎儿生物测量指标，包括双顶径（biparietal diameter, BPD）、腹围（abdominal circumference, AC）、股骨长（femur length, FL）及估计胎儿体重（estimated fetal weight, EFW）。开启超声弹性成像模式，确定参考区域（宫颈外口前唇）与目标区域（宫颈内口前唇）的感兴趣区（region of interest, ROI），通过手动操作经阴道探头施加压缩与舒张循环。在压力峰值且波形规则的区域计算SR，至少重复测量3次，取平均SR值。所有超声检查均由同一名妇科医师使用Voluson S8型超声仪（通用电气医疗集团，美国伊利诺伊州芝加哥，配备4.0~9.0 MHz多频经阴道探头）完成。