Abstract: Objective To explore the influence of different umbilical cord ligation methods on premature infants with a gestational age of less than 34 weeks. 
Methods A total of 388 premature infants with a gestational age of less than 34 weeks were selected and divided into routine group, delayed umbilical cord ligation group and umbilical cord milking group according to the umbilical cord ligation method. In the conventional group, the umbilical cord was ligated within 30 s after delivery. In the delayed umbilical cord ligation group, the umbilical cord was ligated 120 s after delivery. In the umbilical cord milking group(UCM), the procedure was to milk approximately 20 cm from the newborn′s end, milk the umbilical cord from the mother′s end to the newborn′s end for 2-3 times and then ligate the umbilical cord, which took 5-10 s. Venous blood was collected at 48 h and 7 d after birth for detection of hemoglobin(Hb) and hematocrit(HCT), and measure percutaneous bilirubin value 1-7 days after birth. The incidence of phototherapy, one-week anemia, blood transfusion and asphyxia during hospitalization were recorded. 
Results The Hb and HCT level of the delayed umbilical cord ligation group and the umbilical cord milking group at 48 h and 7 d were significantly higher than the routine group, and the differences were statistically significant(P＜0.05), while there was no significant difference in the level of Hb and HCT between the delayed umbilical cord ligation group and the umbilical cord milking group at 48 h and 7 d(P＞0.05). The incidence of one-week anemia and blood transfusion in the delayed umbilical cord ligation group and the milking umbilical cord group was lower than that in the routine group, and the difference was statistically significant(P＜0.05), while there was no significant difference between the delayed umbilical cord ligation group and the umbilical cord milking group(P＞0.05). There was no significant difference in the incidence of phototherapy and asphyxia among three groups(P＞0.05). 
Conclusion Both rapid milking of the umbilical cord and delayed umbilical cord ligation can improve the levels of Hb and HCT of premature infants, reduce the incidence of one-week anemia and blood transfusion, and meanwhile not increase the risk of postnatal asphyxia and phototherapy.

Key words: infant, premature, umbilical cord, jaundice