Purpose. Cesarean scar pregnancy is an extremely rare type of ectopic pregnancy implanted in the myometrium at the site of a previous cesarean section scar. On the other hand, pregnancies are considered low implantations if they are identified in the lower third of the uterus without the sac implanted into the scar and have a better prognosis. Early diagnosis of both types of pregnancies can help avoid serious complications. This study is aimed at investigating the significance of transvaginal ultrasound in the differential diagnosis of cesarean scar pregnancies and pregnancies implanted in the lower uterus. Methods. Ninety-three patients with an average age of 32.7 years (range, 24–43 years) were enrolled in this study, including 66 cesarean scar pregnancies and 27 other pregnancies implanted in the lower uterus, and they were examined by transvaginal ultrasound. Results. We observed significant differences in the relationship between the cesarean sac and the scar, the source of the trophoblastic blood flow, and the thickness of the residual muscle between the cesarean scar pregnancy group and the lower uterus pregnancy group. We established the logistic model to improve the differential diagnosis of cesarean scar pregnancies and pregnancies implanted in the lower uterus. Conclusions. Transvaginal ultrasound is recommended in early pregnancy, especially for patients who have undergone a previous cesarean section delivery.

中文翻译：

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超声参数对剖宫产瘢痕妊娠与其他子宫下段植入妊娠的鉴别诊断

目的。剖宫产瘢痕妊娠是一种极为罕见的异位妊娠，植入之前剖宫产瘢痕部位的子宫肌层。另一方面，如果在子宫下三分之一处发现妊娠而没有将囊植入疤痕中并且预后较好，则妊娠被认为是低植入。对这两种类型的妊娠进行早期诊断有助于避免严重的并发症。本研究旨在探讨经阴道超声在剖宫产瘢痕妊娠和子宫下段植入妊娠鉴别诊断中的意义。方法. 本研究共纳入 93 例患者，平均年龄 32.7 岁（范围 24-43 岁），其中 66 例剖宫产瘢痕妊娠和 27 例其他子宫下段植入妊娠，均经阴道超声检查。结果。我们观察到剖宫产瘢痕妊娠组与子宫下妊娠组在剖宫产囊与瘢痕的关系、滋养细胞血流来源、残余肌肉厚度等方面存在显着差异。我们建立了logistic模型，以提高剖宫产瘢痕妊娠和子宫下段植入妊娠的鉴别诊断。结论. 建议在妊娠早期进行经阴道超声检查，特别是对于曾接受过剖宫产手术的患者。