Delayed Cord Clamping: Can 90 Seconds Make a Difference in Hemodynamic Outcomes?

By Marwa Elgendy, MD, and Hany Aly, MD

When placental mammals give birth, calves stay connected via umbilical cord until the placenta is completely delivered. However, for no obvious reason, human delivery is a different story.

The umbilical cord used to get immediately clamped and separated from the placenta at the time of delivery. Recently, it was discovered that delaying umbilical cord clamping could be beneficial, especially for preterm infants, by allowing passive infusion of umbilical cord blood into the newborns’ circulation, thereby improving their iron storage and decreasing the later need for blood transfusions.

Thus, the American College of Obstetricians and Gynecologists (ACOG) currently recommends a delay in umbilical cord clamping for at least 30 to 60 seconds of delivery.1 Several studies described delayed cord clamping (DCC) practices that ranged from 30 seconds to 5 minutes. 2,3 Nonetheless, the optimal time before DCC is currently unknown and the hemodynamic changes associated with DCC in the immediate postnatal life have not been described.

Therefore, there is an unmet need to investigate the immediate hemodynamic effects of DCC at and beyond 30 seconds in newborns.

Randomized controlled trial evaluates hemodynamic effect of DCC at 30 versus 120 seconds

In this randomized controlled trial,4 our team utilized an electric cardiometry (EC) device, a noninvasive device capable of reliably measuring neonatal hemodynamics.5,6 It has four surface ECG electrodes, like cardiac monitor leads, that can be used in the delivery room. We aimed to study the immediate cardiac hemodynamic effects of DCC at 30 seconds versus 120 seconds. We measured cardiac output (CO), stroke volume (SV), stroke volume index (SVI), cardiac index (CI), index of contractility (ICON), heart rate (HR) and oxygen saturation (SO2). We also measured hemoglobin, bilirubin and glucose concentrations in the blood in the first 24 hours of life. We hypothesized that in full-term infants DCC at 120 seconds would be associated with improved hemodynamic and circulatory changes compared to 30 seconds.

Among 81 pregnant women at term gestation who were eligible for this study, 76 were consented and enrolled. Sixty-eight neonates successfully completed the study; of them, 34 underwent DCC at 30 seconds (group 1) and 34 had DCC at 120 seconds (group 2). There were no significant differences between the two groups regarding the maternal and neonatal demographics and clinical characteristics.

Findings show possible physiological advantages for a longer duration of DCC

Stroke volume was significantly higher in group 2 when compared to group 1 at 5, 10, 15 minutes and 24 hours after birth with p-values = 0.001, 0.015, 0.021 and 0.018, respectively. CO was significantly increased in group 2 compared to group 1 at 5, 10, 15 minutes and 24 hours after birth with p-values: 0.004, 0.042, 0.021 and 0.035, respectively. In addition, SVI was significantly higher in group 2 than in group 1 at 5 minutes (P = 0.005), but it did not differ at the other time points. CI was significantly increased in group 2 compared to group 1 only at 5 minutes after birth, P = 0.025. Index of contractility (ICON) measurements in the two groups showed only a significant increase at 5 minutes in group 2 compared to group 1, (114.2 versus 83.8, P = 004). There were no statistically significant differences in heart rate between the two groups at different time points (P = 0.917, 0.615, 0.546 and 0.898, respectively).

There was a statistically significant change over time in each group in SO2 measurements (P < 0.001 & < 0.001) for group 1 and group 2, respectively. There was no statistically significant change in the cardiac index over time in either group, P = 0.302 and 0.503.

Hemoglobin, hematocrit, and total bilirubin concentrations were significantly increased in group 2 compared to group 1 at 24 hours of life (P < 001, P < 0.001 and P = 0.014, respectively). There were no statistically significant differences between the two groups regarding neonatal direct bilirubin concentration or random blood sugar concentrations. There was no statistically significant difference between groups regarding polycythemia (hematocrit > 65%) and bilirubin nomogram high-risk zones (total bilirubin level > 8 mg/dL).

Future studies are needed in higher-risk neonates

This randomized clinical trial demonstrated that implementation of DCC at 120 seconds of life had significant hemodynamic changes in full-term infants. Cardiac output, cardiac index, stroke volume and stroke volume index were significantly increased in the group of infants with DCC at 120 seconds. The change in cardiac output and stroke volume continued throughout the study period for 24 hours.

This study highlights a possible physiological advantage for a longer duration of DCC to 120 seconds. DCC for 120 seconds did not particularly impose a greater risk for neonatal hyperbilirubinemia. The use of a longer duration of DCC at 120 seconds would need to be studied in higher-risk neonates such as preterm infants.

About the authors: Dr. Elgendy is a neonatology fellow; Dr. Aly is Chair of the Department of Neonatology at Cleveland Clinic Children’s.

References

Committee on Obstetric Practice, American College of Obstetricians and Gynecologists, delayed umbilical cord clamping after birth. Committee Opinion no. 684, Obstet. Gynecol 2017;129: 5–10.

Katheria AC, Brown MK, Faksh A, et al. Delayed cord clamping in newborns born at term at risk for resuscitation: A feasibility randomized clinical trial. J Pediatr 2017; 187:313-17.

Chiruvolu R, Elliott E, Rich D, et al. Effect of delay in cord clamping 45 versus 60 s on very preterm singleton infants. Earl Hum Dev 2018;119:15–8.

Soliman RM, Elgendy MM, Said RN, Shaarawy BI, Helal MM, Aly H. A randomized controlled trial of a 30- versus a 120-sSecond delay in cord clamping after term birth. Am J Perinatol 2022 Feb 15. doi: 10.1055/a-1772-4543. Online ahead of print.

Noori S, Drabu B, Soleymani S, et al. Continuous non-invasive cardiac output measurements in the neonate by electrical velocimetry: a comparison with echocardiography. Arch Dis Child Fetal Neonatal Ed 2012; 97(5):340–43.

Hsu K-H, Wu T-W, Wang Y-C, et al. Hemodynamic reference for neonates of different age and weight: a pilot study with electrical cardiometry. J Perinatol 2016; 36(6):481–5.