Secondary outcomes were delivery before 37 weeks of gestation, shoulder dystocia or birth injury, need for intensive neonatal care, hyperbilirubinemia, and preeclampsia.

• 居异常妊娠结局次位的是妊娠37周前分娩、肩位难产或产伤、需作新生特护、高胆红素血症与子痫前期。