Introduction:
The timing of umbilical cord clamping has been a topic of considerable debate in the medical community, particularly concerning preterm infants. A recent study aimed to shed light on this issue and understand how early or delayed cord clamping affects the health outcomes of these vulnerable newborns.

Methodology:
Researchers conducted a study involving 96 pregnant women eagerly awaiting the arrival of their babies. The participants were randomly assigned to one of two groups - early cord clamping (ECC) or delayed cord clamping (DCC). The researchers closely monitored hematological and cardiac changes in the preterm infants, focusing on gestational periods between 24 and 34 weeks, and evaluated the stability of key blood parameters within the first week after birth.

Key Findings:
The study revealed interesting insights into the impact of cord clamping timing. Infants in the DCC group showed higher levels of hemoglobin and hematocrit upon admission, indicating improved oxygen-carrying capacity compared to those in the ECC group. Similarly, by the seventh day of life, the DCC group maintained higher hemoglobin and hematocrit levels, suggesting continued hematological advantages.

However, it should be noted that the DCC group also had a slightly higher incidence of phototherapy usage to treat jaundice compared to the ECC group.

Cardiac parameters and maternal blood tests did not differ significantly between the two groups.

Conclusion:
The study suggests that delayed cord clamping may have certain benefits for preterm infants in terms of hematological outcomes, as evidenced by higher hemoglobin and hematocrit levels. However, it is important to consider that other factors, such as a slightly increased need for phototherapy, should be taken into account.

This study adds valuable insights to the ongoing discussion regarding the optimal timing for cord clamping in preterm births. Further research is warranted to better understand the long-term implications and overall health outcomes associated with cord clamping practices.

Reference: García, C., Prieto, M.T., Escudero, F., Bosh-Giménez, V., Quesada, L., Lewanczyk, M., Pertegal, M., Delgado, J.L., Blanco-Carnero, J.E., De Paco Matallana, C., 2023. The impact of early versus delayed cord clamping on hematological and cardiovascular changes in preterm newborns between 24 and 34 weeks’ gestation: a randomized clinical trial. Archives of Gynecology and Obstetrics.. https://doi.org/10.1007/s00404-023-07119-0

Dynamics of Umbilical Cord Circulation: During gestation, the fetus relies on the circulation of blood through the umbilical cord to exchange oxygen, carbon dioxide, nutrients, and waste products with the placenta. The fetus and the placenta develop a delicate balance in distributing blood to promote growth and development. Doppler velocimetry of the uteroplacental and fetoplacental circulations is commonly used by obstetricians to assess fetal growth restriction.

Placental Transfusion: After birth, part of the blood contained in the placenta can be transferred back to the newborn, known as placental transfusion. There are several methods to indirectly assess the size of placental transfusion. One such method is measuring the residual placental blood volume (RPBV) after cord clamping. Studies have shown that RPBV decreases from approximately 109 ml to 17 ml when cords are clamped immediately, indicating a smaller transfusion. Similarly, comparing the weight of babies after early and delayed cord clamping shows an average weight gain of 86-96 g in delayed clamping cases, corresponding to a placental transfusion of approximately 30 ml/kg.
Other methods to indirectly demonstrate placental transfusion include measuring neonatal blood volume, which has shown an increase of 14-20 ml/kg in delayed cord clamping cases. Hematocrit and hemoglobin levels in neonates have consistently been found to be higher after delayed cord clamping, with differences of approximately 1.5 g/dL and 10%, respectively. Improved iron stores have also been observed up to 8 months after birth in cases of delayed cord clamping.

Beneficial Effects and Optimal Timing: Delayed cord clamping has been associated with numerous benefits, such as improved iron stores, reduced anemia, enhanced neurodevelopment, and lower transfusion requirements in preterm infants. Studies have shown that waiting at least 2-3 minutes after birth for cord clamping is recommended to achieve optimal outcomes.

Conclusion: Understanding the dynamics of umbilical cord circulation and placental transfusion is essential for healthcare professionals and individuals interested in medicine. Through a review of extensive literature, it is clear that delayed cord clamping leads to various benefits for newborns. Recommending a minimum of 2-3 minutes for cord clamping after birth can help optimize outcomes. Further research and ongoing studies, such as the SAVE-study, contribute to our understanding of sustained cord circulation and its implications for neonatal health.

Read more: https://doi.org/10.1016/j.semperi.2023.151739