Objective To compare the effects of umbilical cord milking and delayed cord clamping on clinical outcomes of preterm infants with gestational age of 28 to 36 weeks born for one week, and to explore whether delayed umbilical cord milking can be used to replace delayed umbilical cord clamping in emergency situations.

Methods A total of 123 premature infants with gestational age of 28 to 36 weeks born in March 2019 to May 2020 were selected as study objects, among whom 60 patients with odd birth dates were included in umbilical cord milking group and 63 patients with even birth dates were included in delayed umbilical cord clamping group. A total of 64 preterm infants of the same gestational age born for six months before implementation of research were selected as immediate umbilical cord clamping group. The indicators within 1 h of birth (blood pressure, body temperature, microscale blood glucose, pH value of umbilical cord blood, hemoglobin) and indicators within 1 week of birth (neonatal anemia, feeding problems, respiratory diseases, incidence of intracranial hemorrhage and blue light therapy rate, oxygen therapy rate) in three groups of premature infants.

Results The systolic blood pressure of premature infants within 1 hour after birth in the umbilical cord milking group and delayed umbilical cord clamping group was(62.70±7.03) mmHg and (61.60±6.06) mmHg, which were higher than (57.02±7.92) mmHg in the immediate umbilical cord clamping group (P < 0.05), but there was no significant difference between the umbilical cord milking group and delayed umbilical cord clamping group in systolic blood pressure(P>0.05). The mean arterial pressure of the umbilical cord milking group was (43.10±6.10) mmHg, which was higher than (41.48±4.13) mmHg in the delayed umbilical cord clamping group and (40.45±6.03) mmHg in the immediate umbilical cord clamping group (P < 0.05), but no significant difference in mean arterial pressure was found between the immediate umbilical cord clamping group and delayed umbilical cord clamping group(P>0.05). The hemoglobin level in 1 hour after birth in the umbilical cord milking group and delayed umbilical cord clamping group was (204.95±22.65) g/L and (205.19±22.15) g/L, which was higher than (191.31±25.70) g/L in the immediate umbilical cord clamping group (P < 0.05), and there was no significant difference in hemoglobin level between the umbilical cord milking group and the delayed umbilical cord clamping group (P>0.05). There were no significant differences in body temperature, umbilical cord blood pH and microblood glucose among the three groups (P>0.05). Within 1 week after birth, the phototherapy rates of the umbilical cord milking group and delayed umbilical cord clamping group were 83.33% and 85.71%, respectively, which were significantly higher than 62.50% in the immediate umbilical cord clamping group (P < 0.05), while the oxygen rates of the umbilical cord milking group and the delayed umbilical cord clamping group were 11.67% and 17.46%, which were significantly lower than 35.94% in the immediate umbilical cord clamping group (P < 0.05). There were no significant differences in anemia, feeding problems, respiratory diseases and incidence of intracranial hemorrhage among the three groups (P>0.05).

Conclusion Umbilical cord milking and delayed umbilical cord clamping can increase postnatal blood pressure and hemoglobin, decrease oxygen therapy rate in preterm infants, and have no increased adverse outcomes. For premature infants aged 28 to 36 weeks, umbilical cord milking can be an alternative for delayed umbilical cord clamping for placental transfusion in emergency situations.