More commonly, lost twins are discovered as tiny mummified attachments to the placenta of the live twin, after it is born.

更常见的是死去的孪生儿变成了微小的干尸，当存活婴儿出生的时候，附在其胎盘上。

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Twin to twin Transfusion Syndrome (TTTS) and other complications of monochorionic (Shared placenta) twin pregnancies like unequal placental sharing are generally diagnosed by ultrasound.

双胞胎输血综合症以及其他单绒毛膜双胞胎怀孕的并发症，比方胎盘分配不均等，普通都是经过超声诊断的。

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Methods One hundred and fourty-one women with high hemorrhagic risk factors including twin pregnancy, polyhydramnios, fetal macrosomia, placenta previa were planned cesarean section.

方法对141例有出血高危因素（双胎、羊水过多、巨大儿、前置胎盘）的产妇行剖宫产术。

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Obese mothers, twin fetuses, and a phenomenon called mosaicism, in which placenta DNA differs from fetal DNA, among other things, could confuse results.

WSJ: New Questions on Cutting-Edge Prenatal Tests