The effect of cord clamping time on oxidant-antioxidant mediators in term and preterm newborns

Although the cord clamping is applied in every birth, a common method has not been determined regarding its duration and technique. Late cord clamping (30-60 sec) applied in previous years has been replaced by early cord clamping (0-29 sec) with increasing number of deliveries. In the context of the change in clamping time, the lack of a clear and common technique has increased the interest in this issue. There is an increase in the production of free oxygen radicals in newborn infants who have undergone a low oxygenation intrauterine environment and a high oxygenated extrauterine environment at birth. Thanks to advances in neonatal medicine, very low weight and immature babies have become possible. In these infants, mechanical ventilation and resuscitation increases the production of free oxygen radicals. However, antioxidant defense system has not been developed enough in newborn infants and especially premature infants. As a result, these infants are at great risk for oxidant stress. The resulting oxidative stress is responsible for the development of many diseases, such as diabetes mellitus, necrotizing enterocolitis (NEC), patent ductus arteriosus (PDA), hypoxic ischemic encephalopathy (HIE), retinopathy of prematurity (ROP), bronchopulmonary dysplasia (BPD), periventricular leukomalacia (PVL), intraventricular hemorrhage (IVH). One of the proposed solutions for the prevention of these diseases is the inhibition of the formation of free oxygen radicals by antioxidant supplementation. The cord clamping time may be effective on the oxidant-antioxidant balance in babies due to mediators that continue to pass through when blood flow continues. OBJECTIVE: In our study we aimed to clarify the effects of cord clamping time on oxidant and antioxidant mediators in term and preterm newborns. MATERIAL AND METHOD: In our study, we included 80 pregnant women who were admitted to the Department of Obstetrics and Gynecology, Ege University Hospital between April 2018 and June 2018 and required cesarean section. Pregnants were divided into two groups, each of which consisted of preterm and term (<37, ≥37) according to their gestational weeks. These groups were then divided into two subgroups, including those that were immediately clamped in their own, and after waiting for at least 30 sec. In the cord blood samples taken during cesarean section, oxidant-antioxidant mediator levels such as catalase, MDA, MPO, HIF1α and PGF2α were measured and the effect of cord clamping time on these mediator levels was aimed. Because of the hemolysis of the blood samples of 2 patients, these patients were excluded from the study and the study was completed with the remaining 78 patients. RESULTS: When the results are evaluated; there was no statistically significant difference between the groups in terms of maternal age, gravida, parity and number of abortion. There were statistically significant results for PGF2α, HIF1α and MDA but no significant results were obtained for catalase and MPO levels. CONCLUSION: Our study showed that late clamping of the umblical cord improves the coping with oxidative stress, especially in preterm newborn babies, thus making the baby more resistant to oxidative stress. Furthermore, there is not enough study on the benefits of late cord clamping for increased cesarean delivery. In our study, only pregnant women who had delivered by cesarean section were included. This is of particular importance due to increasing cesarean rates and the lack of studies in this area. Our aim is to be a leading study for the future studies.