12 weeks 孕12周超声声像图 Images 1, 2, 3: 12 weeks of pregnancy; the images show thin inter-amniotic membrane, placenta and normal amount of the amniotic fluid in both compartments of the monochorionic, diamniotic twin pregnancy. 声像图显示单绒双羊双胎羊水内可见纤细的双层羊膜隔膜、胎盘，每羊膜囊内的羊水量均正常。 Images 4, 5, 6, and 7: 12 weeks of pregnancy; Fetus A; the images show increased nuchal translucency (7.5 mm, septate sonolucent nuchal edema) and abdominal skin edema of the fetus. 胎儿A：声像图显示NT增厚约7.5mm，其内可见分隔，胎儿皮肤水肿。
Image 8, and video 1: 12 weeks of pregnancy; Fetus A; the image 8 shows tricuspid regurgitation; the video 1 shows absent ductus venosus of the fetus A. 图8显示胎儿A三尖瓣反流；视频1显示胎儿A静脉导管缺如。
Image 9, and video 2: 12 weeks of pregnancy; Fetus A; the image 9 shows two umbilical arteries passing around empty urinary bladder; the video 2 shows normal female gender of the fetus A. 图9显示胎儿A膀胱周围的两条脐动脉走行，视频2显示胎儿A的女性生殖器。
Images 10, 11, 12, 13, and 14: 12 weeks of pregnancy; Fetus B; the images show normal nuchal translucency, normal nasal bone, normally filled stomach, single umbilical artery, and normal flow within ductus venosus of the fetus B. 胎儿B：声像图显示NT正常，鼻骨和胃泡正常，单脐动脉以及正常的静脉导管。
20 weeks 20 weeks
Image 15 and videos 3, 4: 20 weeks of pregnancy; Fetus A; massive hydrops of the fetus can be seen. 胎儿A：胎儿广泛水肿。
Video 5 and videos 3, 4: 20 weeks of pregnancy; Fetus A; color Doppler 2D and 3D imaging showing absent ductus venosus of the fetus - umbilical vein after insertion to the abdomen has abnormal direction and connection to portal system). 胎儿A：二维和三维超声均显示静脉导管缺如，脐静脉进入腹部后走行异常，直接与门脉系统相连。
Videos 5, 6: 20 weeks of pregnancy; the video 5 shows hydrothorax and normal morphology of the fetus A; the video 6 shows normal thorax and four chamber view of the heart of the fetus B. 视频5显示胎儿A胸腔积液和正常形态；视频6显示胎儿B胸腔正常，四腔心切面正常。
References
1. Nieuwint A, Van Zalen-Sprock R, Hummel P, Pals G, Van Vugt J, Van Der Harten H, Heins Y, Madan K. 'Identical' twins with discordant karyotypes. Prenat Diagn. 1999 Jan;19(1):72-6. PubMed PMID: 10073913. 2. Bohec C, Douet-Guilbert N, Basinko A, Le Bris MJ, Marcorelles P, Audrézet MP, Tetefort R, Bages K, Collet M, Morel F, De Braekeleer M. Difficult diagnosis and management of an heterokaryotypic monochorionic twin pregnancy with discordant fetal sex and 45,X/47,XYY karyotypes. Fetal Pediatr Pathol. 2010;29(6):424-30. doi: 10.3109/15513815.2010.505630. PubMed PMID: 21043568. 3. Sepulveda W, Wong AE, Ocaranza M. Heterokaryotypic pregnancy: monozygotic monochorionic twins discordant for trisomy 13. Fetal Diagn Ther. 2010;28(2):109-13. doi: 10.1159/000309175. Epub 2010 May 21. PubMed PMID: 20501972.
