探讨超声在单绒毛膜双胎（MCT）妊娠孕期管理中的应用价值。

回顾性选取2018年2月至2021年3月于安徽医科大学第一附属医院超声诊断为MCT妊娠并随访到妊娠结局者153例。将其分为2组，自孕早期开始至妊娠结束出现一胎或双胎发育异常者（异常组）65例，双胎发育均未发现异常者（正常组）88例。自发现MCT妊娠开始每2周超声监测双胎生长发育及附属物情况，孕20~24周胎儿结构系统筛查，伴有双胎特有并发症等需要密切监测者每周一次超声复查。分析比较异常组与正常组的妊娠结局。

异常组65例（130个胎儿）中，13例发生孕早期一胎自减或流产，共存活新生儿8个，活产率为31%（8/26）；孕中期流产4例，无存活（0/8）；双胎输血综合征（TTTS）10例（Ⅰ期4例，Ⅱ期 2例，Ⅲ期1例，Ⅴ期3例），存活新生儿10个，活产率为50%（10/20）；双胎贫血-红细胞增多序列征（TAPS）3例，其中TAPS合并TTTS 1例，存活新生儿4个，活产率为67%（4/6）；双胎反向动脉灌注序列征（TRAPS）3例，存活新生儿1个，活产率为17%（1/6）；选择性宫内生长受限（sIUGR）14例（Ⅰ型6例，Ⅱ型2例，Ⅲ型6例），存活新生儿23例，活产率为82%（23/28）；双胎之一结构畸形18例，存活新生儿21个，活产率为58%（21/36）。联体双胎2例（4胎），无存活。异常组的活产率（49%，64/130）显著低于正常组（100%，176/176），差异有统计学意义（P＜0.001）。

MCT妊娠并发症发生率高，活产率低，产前超声可及时发现并全程管理妊娠过程可能发生的异常情况，为临床决策和产前咨询提供重要参考依据。

To assess clinical value of ultrasound in the management of monochorionic twin (MCT) pregnancies.

A total of 153 MCT pregnancies diagnosed by ultrasound at The First Affiliated Hospital of Anhui Medical University from February 2018 to March 2021 were selected for retrospective analysis, all of which were followed until the end of pregnancies. Fetuses in 65 cases were found to have ultrasonic abnormalities during the pregnancy (abnormal group), and the remaining 88 cases were included in a normal group. The diagnosis of MCTs was made on the basis of early ultrasound findings and confirmed at delivery. Fetal ultrasound biometry measurements and growth parameters were used to monitor the fetus every two weeks or even once a week if complications arose from the first trimester to third trimester. Fetal ultrasound screening for anomalies was performed at gestational weeks 20-24.

In the abnormal group, 13 cases had embryo arrest or reduction in the first trimester and the live birth rate was 31%. There were four abortions in the second trimester. Twin-twin transfusion syndrome (TTTS) was diagnosed in 10 cases (20 fetuses) (4 in stage Ⅰ, 2 in stage Ⅱ, 1 in stage Ⅲ, and 3 in stage Ⅴ); there were 10 neonates alive, and the live birth rate was 50%. Twin anaemia polycytosis sequence (TAPS) was diagnosed in three cases (6 fetuses) and one case was complicated with TTTS; four neonates survived and the live birth rate was 67%. There were three cases (6 fetuses) with twin reversed arterial perfusion sequence (TRAPS); two neonates survived and the live birth rate was 29%. There were 14 cases of selective intrauterine growth restriction (sIUGR) (28 fetuses) (6 cases of type Ⅰ, 2 cases of type Ⅱ, and 6 cases of type Ⅲ); 23 neonates survived, and the live birth rate was 82%. There were 18 cases (36 fetuses) with structural malformations in one of the twins; 21 neonates survived and the live birth rate was 58%. There were two cases of conjoined twins (4 fetuses) and none survived. The live birth rate of MCTs in the abnormal group (49%, 64/130) was significantly lower than that in the normal group (100%, 176/176; P<0.001).

The complication rate and fetal loss rate of MCTs are high. Prenatal ultrasound can detect and manage all kinds of abnormal conditions that may occur during pregnancy in time. Due to the limitations of the clinical examination of twins, prenatal ultrasound, as a screening and monitoring method of MCT, provides an important reference for the clinical decision and prenatal consultation during pregnancy.