The condition of monozygotic, monochorionic triplet fetuses with a pair of conjoined twins is extremely rare (close to one in a million births), presents challenges in its management, and with poor prognosis.

中文翻译：

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单绒毛膜三胞胎妊娠并发连体婴和早期双胎输血综合征

单卵、单绒毛膜三胞胎与一对连体双胞胎的情况极为罕见（接近百万分之一），其治疗面临挑战，且预后不良。