Fetal Hemoglobin in Preterm Infants After Resuscitation with Immediate Cord Clamping, Delayed Cord Clamping, or Cord Milking

Background: Fetal hemoglobin (HbF) plays a beneficial role in the progressive adaptation to the postnatal oxygen-rich environment in preterm infants due to its peculiar properties. Our aim was to evaluate if preterm infants resuscitated with delayed cord clamping (DCC) or umbilical cord milking (UCM) might have higher and more durable HbF levels than infants resuscitated with immediate cord clamping (ICC). Methods: We retrospectively studied 181 preterm infants born at <30 weeks of gestation, among whom 120 were resuscitated with ICC, 30 with DCC, and 31 with UCM. Mean values of HbF blood levels in the first postnatal week (HbF1st _week); in the 14th, 21st, and 28th days of life (HbF_{14–21–28 DOL}); and in the 31st, 34th, and 36th weeks of postmenstrual age (HbF_{31–34–36 weeks}) were calculated. Results: We found that HbF1st _week (15.3 ± 3.4 vs. 12.6 ± 3.5 g/dL, p < 0.001), HbF_{14–21–28 DOL}, (9.3 ± 3.2 vs. 7.6 ± 3.6 g/dL, p = 0.018), and Hb_{–34–36 weeks} (7.5 ± 3.6 vs. 5.7 ± 3.6 g/dL, p = 0.014) levels were higher in the UCM than in the ICC group. No differences of HbF levels were found between the DCC and ICC groups. Conclusions: UCM was associated with a persistent higher level of HbF than ICC. The effect of DCC was less marked as HbF level was higher than ICC only in the first week of life. UCM and DCC may help counteract the negative effects of blood sampling and transfusions on HbF levels.