中文摘要：

目的探讨超声孕早期绒毛膜性鉴定及监测双胎妊娠风险的价值。方法选取250例孕早期超声确定为双胎妊娠的孕妇，探讨并研究其妊娠风险，对其妊娠情况进行超声监测。结果孕早期超声鉴定绒毛膜性：双绒毛膜囊双羊毛膜囊双胎（DCDA）158例，单绒毛膜囊双羊毛膜囊双胎（MCDA）89例，单绒毛膜囊单羊毛膜囊双胎（MCMA）3例。超声监测双胎妊娠：足月产133例，早产78例，流产或双胎之一丢失39例。双胎输血综合征（rIWS）7例，双胎反向动脉灌注序列综合征（TRAP）2例，连体双胎1例，选择性胎儿宫内生长受限（sIUGR）28例，一胎或双胎畸形6例，晚孕原因不明的一胎或双胎胎死宫内（sIUFD）5例。孕母并发症监测：妊娠期高血压疾病30例。结论采用超声孕早期绒毛膜性鉴定确定双胎类型，预测及防范双胎妊娠风险，对不同类型的双胎可能出现的异常情况进行监测，可为临床干预及处理提供依据，意义重大。

英文摘要：

Objective To explore chorionicity identification during the first trimester of pregnancy and the value of risk monitoring of twin pregnancy. Methods A total of 250 cases of twin pregnancies diagnosed definitely by ultrasonography during the first trimester of pregnancy were selected, the risk of pregnancy was studied, the pregnancy situations were monitored by ultrasound. Results The results of chorionicity identification： 158 cases were found with dichorionic diamniotic twins （DCDA） , 89 cases were found with monochorionic diamniotic twins （MCDA）, and 3 cases were found with monochorionic monoamniotic twins （MCMA） . Pregnancy outcomes monitored by ultrasound： 133 cases were full-term delivery, 78 cases were premature delivery, 39 cases were abortion or prenatal death of twin. Seven cases were found with twin to twin transfusion syndrome （TITS）, two cases were found with twin reversed arterial perfusion sequence syndrome （TRAP）, one case was found with conjoined twins, twenty-eight cases were found with selective intrauterine growth restriction （sIUGR）, six cases were found with twin or twins deformity, five cases were found with unknown intrauterine death of twin or twins （sIUFD） . Maternal complications： 30 cases were found with hypertensive disorder complicating pregnancy. Conclusion Confirming the types of twins by chorionicity identification via uhrasonography, predicting and preventing the risk of twin pregnancy, and monitoring the probable abnormal situations existing in different types of twin pregnancy can provide a basis for clinical intervention and treatment, which is of great significance.