A physiologic approach to cord clamping: Clinical issues

Outcomes of Neonatal Resuscitation With and Without an Intact Umbilical Cord: A Meta-Analysis

Around the world, very few babies require a more intensive resuscitative effort for stabilization. The optimal timing of an intact umbilical cord to help with resuscitation is controversial. Our objective in the review is to compare the outcomes of neonatal resuscitation with and without an intact umbilical cord. A search of six electronic database libraries was explored for data released between 2014 and 2023. A manual search of secondary references in relevant studies was also performed. Studies focused only on randomized controlled trials comparing the outcomes of neonatal resuscitation with and without an intact umbilical cord at any gestational age. Two reviewers retrieved data for relevant outcomes and independently evaluated trial quality and eligibility. Mortality rate and APGAR (appearance, pulse, grimace, activity, and respiration) scores were noted as common in the two studies. Four randomized control trials were assessed for the impact of delayed cord clamping on neonates. One study focused on neurodevelopmental outcomes and noted significant improvement. Other studies noted delayed clamping as beneficial for improving oxygen saturation, APGAR score, and mortality rate. The meta-analysis included three controlled trials with a total of 528 babies and tested the effects of clamping the umbilical cord either late (n = 264) or early (n = 264). The heterogeneity of mortality and APGAR score at 5 minutes were not significant, which may be because only two studies of each case were available to compare. We concluded that very few studies are available to identify a significant impact of delayed cord clamping in neonates. However, delayed clamping for up to 5 minutes is noted as beneficial to the newborn.

Effect of Delayed Umbilical Cord Clamping on Hemodynamic Instability in Preterm Neonates below 35 Weeks

INTRODUCTION

Delaying umbilical cord clamping facilitates postnatal transition in neonates but evidence on its effect in reducing hemodynamic instability in preterm neonates is inconclusive.

AIMS

To evaluate delayed cord clamping (DCC) in reducing the incidence of hemodynamic instability in preterm neonates below 35 weeks gestational age admitted to the neonatal intensive care unit.

METHODS

Neonates between 25 weeks and 34 weeks and 6 days gestation were enrolled. Hemodynamic and respiratory parameters were monitored over 48 h. Hemodynamic instability was defined as persistent tachycardia and/or hypotension necessitating therapy.

RESULTS

The DCC cohort included 62 neonates with an equal number in the non-DCC group. The birth weight [mean ± standard deviation (SD)] was 1332.90 ± 390.05 g and the gestational age (mean ± SD) was 31.64 ± 2.52 weeks. Hemodynamic instability was noted in 18/62 (29%) neonates in the DCC cohort and 29/62 (46.7%) in the non-DCC group; relative risk (RR) 0.62 [95% confidence interval (CI) 0.38-0.99] (p = 0.023). The duration of inotrope requirement in the DCC cohort (mean ± SD) was 38.38 ± 16.99 h compared to 49.13 ± 22.90 h in the non-DCC cohort (p = 0.090). Significantly higher systolic, diastolic and mean arterial pressures were noted from 6 h to 48 h in the DCC cohort (p < 0.001). The severity of respiratory distress and FiO2 requirement was also less in the first 24 h. There was no difference in the incidence of patent ductus arteriosus, late-onset sepsis or mortality.

CONCLUSION

Delaying umbilical cord clamping at birth by 60 s resulted in significantly lower hemodynamic instability in the first 48 h and higher blood pressure parameters.

Factors associated with umbilical cord clamping in term newborns

OBJECTIVE

To identify factors associated with umbilical cord clamping in term newborns and to compare the recording of clamping time in the medical record with what was observed.

METHOD

Cross-sectional study, with 300 mothers-infants, in a university hospital. Clamping time and medical records were observed, and a structured questionnaire was applied to postpartum women for sociodemographic variables. Bivariate analysis, multivariate Poisson Regression model, and Kappa concordance test were performed.

RESULTS

The percentage of late/optimal clamping observed was 53.7%. The associated factors were skin-to-skin contact in the delivery room (PR = 0.76; 0.61-0.95; p = 0.014), position of the newborn below the vaginal canal (PR = 2.6; CI95%: 1.66-4.07; p < 0.001), position of the newborn at the vaginal level (PR = 2.03; CI95%: 1.5-2.75; p < 0.001), and need for newborn resuscitation in the delivery room (PR = 1.42; CI95%; 1.16-1.73; p = 0.001). Kappa concordance level of the professionals, records compared to the observation was: nurse 0.47, obstetrician 0.59, and pediatrician 0.86.

CONCLUSION

the identification of associated factors and the comparison between recording and observing the clamping time can help in the planning and implementation of improvements for adherence to good practices at birth.

Placental Transfusion, Timing of Plastic Wrap or Bag Placement, and Preterm Neonates

OBJECTIVE

 Compare delivery room practices and outcomes of infants born at less than 32 weeks' gestation or less than 1,500 g who have plastic wrap/bag placement simultaneously during placental transfusion to those receiving plastic wrap/bag placement sequentially following placental transfusion.

STUDY DESIGN

 Retrospective analysis of data from a multisite quality improvement initiative to refine stabilization procedures pertaining to placental transfusion and thermoregulation using a plastic wrap/bag. Delivery room practices and outcome data in 590 total cases receiving placental transfusion were controlled for propensity score matching and hospital of birth.

RESULTS

 The simultaneous and sequential groups were similar in demographic and most outcome metrics. The simultaneous group had longer duration of delayed cord clamping compared with the sequential group (42.3 ± 14.8 vs. 34.1 ± 10.3 seconds, p < 0.001), and fewer number of times cord milking was performed (0.41 ± 1.26 vs. 0.86 ± 1.92 seconds, p < 0.001). The time to initiate respiratory support was also significantly shorter in the simultaneous group (97.2 ± 100.6 vs. 125.2 ± 177.6 seconds, p = 0.02). The combined outcome of death or necrotizing enterocolitis in the simultaneous group was more frequent than in the sequential group (15.3 vs. 9.3%, p = 0.038); all other outcomes measured were similar.

CONCLUSION

 Timing of plastic wrap/bag placement during placental transfusion did affect duration of delayed cord clamping, number of times cord milking was performed, and time to initiate respiratory support in the delivery room but did not alter birth hospital outcomes or respiratory care practices other than the combined outcome of death or necrotizing enterocolitis.

KEY POINTS

· Plastic bag placement during placental transfusion is effective in stabilization of preterms.. · Plastic bag placement after placental transfusion is effective in stabilization of preterms.. · Plastic bag placement during placental transfusion and risk of death or necrotizing enterocolitis needs additional study..

Delivery room care and neonatal resuscitation while on intact placental circulation: an open-label, single-arm study

OBJECTIVE

To assess feasibility, safety, usability and learnability of delivery room care and resuscitation with intact placental circulation (RIPC) at mother's bedside.

MATERIALS AND METHODS

We included neonates ≥24 weeks GA after parental consent. Both in vigorous and babies requiring resuscitation, appropriate steps of resuscitation were provided with intact cord till 3 min using RIPC warmer. Outcomes were assessed by set criteria and standard system usability scale.

RESULTS

Of 380 enrolled, intervention was feasible in 376 babies (98.9%). Safety criteria were met in all 376 babies received onto the trolley (100%). Median GA was 38 (37-39) weeks and median BW 2740 (2330-3120) g. Of 376, 92 required resuscitation; 90 (97.8%) PPV, 49 (53.2%) intubations and 13 (14.1%) chest compressions. System Usability Score rated >68 (good) in 90% and 52-68 (fair) in 10%. Temperature at 5 min was 36.5 ± 0.1.

CONCLUSIONS

Delivery room care and neonatal RIPC is feasible and safe across gestations.

Vascular dimorphism ensured by regulated proteoglycan dynamics favors rapid umbilical artery closure at birth

The umbilical artery lumen closes rapidly at birth, preventing neonatal blood loss, whereas the umbilical vein remains patent longer. Here, analysis of umbilical cords from humans and other mammals identified differential arterial-venous proteoglycan dynamics as a determinant of these contrasting vascular responses. The umbilical artery, but not the vein, has an inner layer enriched in the hydrated proteoglycan aggrecan, external to which lie contraction-primed smooth muscle cells (SMC). At birth, SMC contraction drives inner layer buckling and centripetal displacement to occlude the arterial lumen, a mechanism revealed by biomechanical observations and confirmed by computational analyses. This vascular dimorphism arises from spatially regulated proteoglycan expression and breakdown. Mice lacking aggrecan or the metalloprotease ADAMTS1, which degrades proteoglycans, demonstrate their opposing roles in umbilical vascular dimorphism, including effects on SMC differentiation. Umbilical vessel dimorphism is conserved in mammals, suggesting that differential proteoglycan dynamics and inner layer buckling were positively selected during evolution.

Umbilical Cord Practices of Members of the American College of Nurse-Midwives

INTRODUCTION

Mercer et al surveyed members of the American College of Nurse-Midwives (ACNM) about their umbilical cord clamping practices in 2000. Over the last 20 years, a significant body of research supporting delayed cord clamping (DCC) has been published. The purpose of this study was to learn how midwives today manage the umbilical cord at birth.

METHODS

To better understand the current practices of midwives, in 2017, a national online survey of ACNM members was conducted. A total of 24 questions were asked about DCC, cord milking, specific clinical circumstances, and the presence of policies or guidelines.

RESULTS

A total of 5306 surveys were sent with 1106 responses. After applying inclusion criteria, 1050 were available for analysis. Respondents practiced in all settings: home, birth centers, and hospitals. Compared with 2000, a 46% increase in the practice of DCC was identified. In this study, 98% of the participants reported facilitating DCC for full-term vaginal births as compared with 67% in 2000. In addition, 25% practiced DCC for near-term and 65% for preterm neonates. Cord milking was practiced by 37% of participants. When asked about barriers to practicing DCC, 54% of participants identified time pressures to hand off the newborn as the greatest detriment. It was challenging to practice DCC in situations wherein the newborn needed resuscitation or in breech births. Far fewer midwives practice cord milking compared with DCC.

DISCUSSION

The survey results suggest there has been an increase in the practice of DCC over the last 20 years. Cord milking is not as widely practiced as DCC, and respondents were less likely to be convinced by the evidence for cord milking. This speaks to the opportunity for more education for midwives. There is also a need for clinical guidelines that address umbilical cord management when challenging circumstances arise such as breech birth, shoulder dystocia, and the need for resuscitation.

Delayed cord clamping is associated with improved dynamic cerebral autoregulation and decreased incidence of intraventricular hemorrhage in preterm infants

Delayed cord clamping (DCC) improves neurologic outcomes in preterm infants through a reduction in intraventricular hemorrhage (IVH) incidence. The mechanism behind this neuroprotective effect is not known. Infants born <28 wk gestation were recruited for longitudinal monitoring. All infants underwent 72 h of synchronized near-infrared spectroscopy (NIRS) and mean arterial blood pressure (MABP) recording within 24 h of birth. Infants with DCC were compared with control infants with immediate cord clamping (ICC), controlling for severity of illness [clinical risk index for babies (CRIB-II) score], chorioamnionitis, antenatal steroids, sedation, inotropes, and delivery mode. Autoregulatory dampening was calculated as the transfer function gain coefficient between the MABP and NIRS signals. Forty-five infants were included (DCC; n = 15, paired 2:1 with ICC controls n = 30). ICC and DCC groups were similar including gestational age (25.5 vs. 25.2 wk, P = 0.48), birth weight (852.3 vs. 816.6 g, P = 0.73), percent female (40 vs. 40%, P = 0.75), and dopamine usage (27 vs. 23%, P = 1.00). There was a significant difference in IVH incidence between the DCC and ICC groups (20 vs. 50%, P = 0.04). Mean MABP was not different (35.9 vs. 35.1 mmHg, P = 0.44). Compared with the DCC group, the ICC group had diminished autoregulatory dampening capacity (-12.96 vs. -15.06 dB, P = 0.01), which remained significant when controlling for confounders. Dampening capacity was, in turn, strongly associated with decreased risk of IVH (odds ratio = 0.14, P < 0.01). The results of this pilot study demonstrate that DCC is associated with improved dynamic cerebral autoregulatory function and may be the mechanism behind the decreased incidence of IVH. NEW & NOTEWORTHY The neuroprotective mechanism of delayed cord clamping in premature infants is unclear. Delayed cord clamping was associated with improved cerebral autoregulatory function and a marked decrease in intraventricular hemorrhage (IVH). Improved dynamic cerebral autoregulation may decrease arterial baroreceptor sensitivity, thereby reducing the risk of IVH.

Clinical aspects of incorporating cord clamping into stabilisation of preterm infants

Fetal to neonatal transition is characterised by major pulmonary and haemodynamic changes occurring in a short period of time. In the international neonatal resuscitation guidelines, comprehensive recommendations are available on supporting pulmonary transition and delaying clamping of the cord in preterm infants. Recent experimental studies demonstrated that the pulmonary and haemodynamic transition are intimately linked, could influence each other and that the timing of umbilical cord clamping should be incorporated into the respiratory stabilisation. We reviewed the current knowledge on how to incorporate cord clamping into stabilisation of preterm infants and the physiological-based cord clamping (PBCC) approach, with the infant's transitional status as key determinant of timing of cord clamping. This approach could result in optimal timing of cord clamping and has the potential to reduce major morbidities and mortality in preterm infants.

Golden hour of neonatal life: Need of the hour

"Golden Hour" of neonatal life is defined as the first hour of post-natal life in both preterm and term neonates. This concept in neonatology has been adopted from adult trauma where the initial first hour of trauma management is considered as golden hour. The "Golden hour" concept includes practicing all the evidence based intervention for term and preterm neonates, in the initial sixty minutes of postnatal life for better long-term outcome. Although the current evidence supports the concept of golden hour in preterm and still there is no evidence seeking the benefit of golden hour approach in term neonates, but neonatologist around the globe feel the importance of golden hour concept equally in both preterm and term neonates. Initial first hour of neonatal life includes neonatal resuscitation, post-resuscitation care, transportation of sick newborn to neonatal intensive care unit, respiratory and cardiovascular support and initial course in nursery. The studies that evaluated the concept of golden hour in preterm neonates showed marked reduction in hypothermia, hypoglycemia, intraventricular hemorrhage (IVH), bronchopulmonary dysplasia (BPD), and retinopathy of prematurity (ROP). In this review article, we will discuss various components of neonatal care that are included in "Golden hour" of preterm and term neonatal care.

Golden 60 minutes of newborn's life: Part 2: Term neonate

The concept of "Golden 60 minutes" or "Golden Hour" has been derived from adult trauma. It has been defined as the first 60 min of postnatal life. It has been seen that care received by any newborn in the initial first hour has implications in the future life, showing the importance of golden hour. The major cause of neonatal mortality term newborn is asphyxia, which can be reduced with effective resuscitation. In golden hour approach for term newborn, the importance is given to effective and evidence based resuscitation, post-resuscitation care, delayed cord clamping, prevention of hypothermia, immediate breast feeding, prevention of hypoglycemia, and starting of therapeutic hypothermia in case of moderate to severe asphyxia. In this part of review, we will cover all the golden hour interventions in term neonate with current evidence.

Factors contributing to postpartum blood-loss in low-risk mothers through expectant management in Japanese birth centres

OBJECTIVE

To describe aspects of expectant midwifery care for low-risk women conducted in midwifery-managed birth centres during the first two critical hours after delivery and to compare differences between midwifery care, client factors and postpartum blood loss volume.

METHOD

As a secondary analysis from a larger study, this descriptive retrospective study examined data from birth records of 4051 women who birthed from 2001 to 2006 at nine (21%) of the 43 midwifery centres in Tokyo. Nonparametric and parametric analyses identified factors related to increased blood loss. Interviews to establish sequence of midwifery care were conducted.

FINDINGS

The midwifery centres provided care based on expectant management principles from birth to after expulsion of the placenta. Approximately 63.3% of women were within the normal limits of blood loss volume under 500g. A minority of women (12.9%) experienced blood loss between 500 and 800g and 4% had blood loss exceeding 1000g. Blood loss volume tended to increase with infant birth weight and duration of delivery. The total blood loss volume was significantly higher for primiparas than for multiparas during the critical two hours after delivery and for immediately after delivery, yet blood loss volume was significantly higher for multiparas than for primiparas during the first hour after delivery. Preventive uterine massage and umbilical cord clamping after placenta expulsion resulted in statistically significant less blood loss. Identified were two patterns of midwifery care based on expectant management principles from birth to after expulsion of the placenta. The practice of expectant management was not a significant factor for increased postpartum blood loss.

CONCLUSION

These results detail specific midwifery practices and highlight the clinical significance of expectant management with low risk pregnant women experiencing a normal delivery.