脐带破裂所致胎儿失血
Fetal blood loss from ruptured cord
双胎之另一胎儿的脐带断端所致胎儿失血
Fetal blood loss from cut end of co-twin’s cord
母血胎儿DNA
Fetal DNA in maternal blood
胎儿脐带绕颈
Fetal umbilical cord around neck
Nuchal encirclements of umbilical cord
胎儿胎盘循环
fetoplacental circulation