Abstract：
Fetal megacystis is a sonographic sign, defined in first trimester as a longitudinal bladder length (LBD)>7 mm. Different causes may be associated with megacystis and outcomes vary with many factors. There are no international guidelines on how to manage megacystis cases, and invasive testing is controversial when no other abnormalities are found. The main objective of this study is to compare etiologies, management and outcomes of fetuses with first trimester megacystis, specifically between groups of LBD≤15 mm and >15 mm. This is a retrospective cohort study of megacystis cases managed in a Prenatal Diagnosis Center, between January 2009 and September 2020. Descriptive and bivariate analysis were performed. We studied 43 fetuses: 67.4% with LBD≤15 mm and 32.6% with LBD>15 mm. We found an association between LBD and isolated Low Urinary Tract Obstruction (LUTO) (3.4% vs 64.3%; p<0.001) and with isolated megacystis (44.8% vs 0.0%; p = 0.001). No differences were seen regarding the presence of aneuploidies (31.0% vs 14.3%; p = 0.213). Invasive testing was performed in 93.0% of cases. Overall, we report 41.9% of live births, 39.5% of pregnancy termination and 18.6% of intrauterine fetal demise. We found a higher rate of live births in fetuses with LBD≤15 mm (55.2% vs 14.3%; p = 0.011). For a mean follow-up time of 20.6 months, we report one neonatal death and one case of renal insufficiency. In conclusion, isolated LUTO is more frequent if LBD>15 mm whereas isolated megacystis is more frequently found if LBD≤15 mm. If LBD≤15 mm, live birth rates and long-term outcomes seem to be enhanced.
摘要：
胎儿巨囊肿是一种超声征象,在妊娠早期定义为纵向膀胱长度（LBD）>7毫米。不同的原因可能与巨细胞相关，结果因许多因素而异。国际上没有关于如何管理巨蛋病例的准则,当没有发现其他异常时，侵入性测试是有争议的。这项研究的主要目的是比较病因，妊娠早期巨大的胎儿的管理和结果，特别是LBD≤15mm和>15mm组之间。这是一项在产前诊断中心管理的巨细胞病病例的回顾性队列研究。2009年1月至2020年9月。进行描述性和双变量分析。我们研究了43个胎儿：LBD≤15mm的胎儿占67.4%，LBD>15mm的胎儿占32.6%。我们发现LBD与孤立的低尿路梗阻（LUTO）（3.4％vs64.3％；p<0.001）和孤立的巨膀胱（44.8％vs0.0％；p=0.001）之间存在关联。关于非整倍体的存在没有观察到差异(31.0%对14.3%;p=0.213)。在93.0％的病例中进行了侵入性测试。总的来说,我们报告了41.9%的活产，39.5%的妊娠终止和18.6%的宫内胎儿死亡。我们发现LBD≤15mm胎儿的活产率较高（55.2％vs14.3％；p=0.011）。平均随访时间为20.6个月，我们报告1例新生儿死亡和1例肾功能不全。总之,如果LBD>15mm，则孤立的LUTO更常见，而如果LBD≤15mm，则孤立的巨细胞更常见。如果LBD≤15mm,活产率和长期结局似乎有所提高.
