Optimal timing of umbilical cord clamping: Is the debate settled? Part 2 of 2: Evidence in preterm and term infants, alternatives, and unanswered questions

In the middle of the 20th century, practices regarding the timing of umbilical cord clamping changed from delaying cord clamping to clamping the umbilical cord soon after delivery of the infant. In the last several years, interest in reviving delayed cord clamping has led to an abundance of literature on the subject. On the basis of recent research, many professional organizations in the fields of obstetrics, midwifery, and pediatrics have started to recommend the use of delayed cord clamping for at least a subset of infants. In part 1 of this 2-part review, we presented the history of the delayed cord clamping debate, discussed the rationale behind the use of delayed cord clamping from a physiologic standpoint, detailed the factors that affect transfusion volume during a delay in cord clamping, and examined the concerns that exist regarding the use of delayed cord clamping. In part 2, we present the evidence surrounding timing of cord clamping for the preterm and term infant and maternal outcomes. Finally, we discuss alternatives to delayed cord clamping and present a summary of unanswered questions on the subject.