Early umbilical cord clamping contributes to elevated blood lead levels among infants with higher lead exposure

Timing of umbilical cord clamping among infants with congenital heart disease

The optimal timing of clamping and cutting the umbilical cord at birth among infants with congenital heart disease (CHD) remains a subject of controversy and debate. The benefits of delayed umbilical cord clamping (DCC) among term infants without CHD are well described, but the evidence base for DCC among infants with CHD has not been characterized adequately. The goals of the present review are to: 1) compare outcomes of DCC versus early cord clamping (ECC) in term (≥37 weeks of gestation) infants; 2) discuss potential risk/benefit profiles in applying DCC among term infants with CHD; 3) use rigorous systematic review methodology to assess the quality and quantity of published reports on cord clamping practices among term infants with CHD; 4) identify needs and opportunities for future research and interdisciplinary collaboration. Our systematic review shows that previous trials have largely excluded infants with CHD. Therefore, the supposition that DCC is advantageous because it is associated with improved neurologic and hematologic outcome is untested in the CHD population. Given that CHD is markedly heterogeneous, to minimize unnecessary and potentially harmful cord clamping practices, identification of subgroups (single-ventricle, cyanotic lesions) most likely to benefit from optimal cord clamping practices is necessary to optimize risk/benefit profiles. The available evidence base suggests that contemporary, pragmatic, randomized controlled trials comparing DCC with ECC among infants with CHD are needed.

Effects of delayed cord clamping on infants after neonatal period: A systematic review and meta-analysis

BACKGROUND

The majority of current evidences simply showed the short-term benefits of delayed cord clamping, mainly focusing on the first week after birth. Without follow-up data, we can hardly come to the conclusion that delayed cord clamping may do more harm than good.

OBJECTIVE

To evaluate the long-term effects of delayed cord clamping compared with early cord clamping on infants after neonatal period.

DESIGN

Systematic review and meta-analysis of randomized controlled trials (RCTs).

DATA SOURCES

PubMed, EMBASE, and the Cochrane Library were systematically searched from inception date to June 22, 2018 for randomized clinical trials comparing early cord clamping with delayed cord clamping in infants beyond 1 month of age.

REVIEW METHODS

Two reviewers independently assessed trial eligibility and quality and extracted all infants' follow-up data after one month of age, which were divided into two groups for analysis, with follow-up periods of less than 6 months (<6 months) and beyond 6 months (≥6 months) respectively.

RESULTS

A total of twenty RCTs were identified and included in this study. All data of the twenty studies were pooled for final meta-analysis (3733 infants). Among preterm deliveries, delayed cord clamping slightly increased hematocrit (6-10 weeks) and serum ferritin (6-10 weeks). For term infants, delayed cord clamping reduced the incidence of anemia after six months of age (≥6 months), iron deficiency (< 6 months, ≥6 months) and iron deficiency anemia (4-12 months), while increased mean corpuscular volume before six months of age (< 6 months), hemoglobin after six months of age (≥6 months), serum iron (2-4 months), total body iron (4-6 months), serum ferritin (< 6 months, ≥6 months) and transferrin saturation (2-12 months). There were no significant differences between early versus late cord clamping groups for other variables.

CONCLUSION

Delayed cord clamping modestly improved hematological and iron status of both preterm and term infants after neonatal period. This affords cogent evidence on the practice of delayed cord clamping for medical staff, especially for countries and regions suffering from relatively higher prevalence rate of iron deficiency during infancy and childhood.

Early Versus Delayed Umbilical Cord Clamping on Physiologic Anemia of the Term Newborn Infant

AIM

Our study aims to make a comparison between the effects of milking of umbilical cord versus delayed cord clamping on Hemoglobin level at 6 weeks from delivery among term neonates and which method is more beneficial for them.

DESIGN

It was a randomised control study. Participants were randomised into 2 groups; Group 1: 125 women were assigned to delay cord clamping; Group 2: 125 women were assigned to milking of the umbilical cord 5 times before cutting. Student t-test was used to compare between the two groups for quantitative data, for qualitative data chi-square test and the Correlation coefficient was done to test the association between variables.

SETTING

This study was at El-Galaa Teaching Hospital, labour suite. Cairo, Egypt.

PARTICIPANTS

A group of 250 pregnant women starting from ≥ 37 weeks' gestational age.

INTERVENTION

In this study, we searched if the mechanism of milking or delayed cord clamping could give some of the positive benefits for neonates or not.

RESULTS

In this study, we found that milking of the umbilical cord five times as in group 1 was associated with higher hemoglobin levels at 6 weeks after birth, at physiological anemia of the fetus and significant but clinically there was no difference between the two groups (10.4 ± 0.5 and 10.6 ± 0.5 respectively, P < 0.001). Also, there was a positive correlation between haemoglobin of the mother and the newborn during the first day and after 6 weeks with r = 0.349 and 0.283 respectively and a P value < 0.001. Furthermore, there was a positive correlation between the haemoglobin of the fetus after the first day and fetus at 6 weeks with r = 0.534 and a P value < 0.001. For most other outcomes (including APGAR score, positive pressure ventilation, poor neonatal outcomes such as respiratory distress syndrome there were no significant differences between the two groups. Our study may recommend the use of umbilical cord milking in term babies when delayed cord clamping is unavailable.

CONCLUSION

Umbilical cord blood milking after its clamping improves some important haematological parameters for newborns, especially in countries with high incidence of anaemia in newborns and children.

Umbilical cord milking at birth for term newborns with acidosis: neonatal outcomes

OBJECTIVE

To determine if umbilical cord milking is detrimental in compromised term/near-term infants.

STUDY DESIGN

A retrospective analysis of infants with abnormal cord gases (cord arterial or venous pH of ≤ 7.1 or base deficit > -12). We collected maternal risk factors, cord management, birth, and neonatal outcomes during hospitalization.

RESULT

We found 157 infants who met the criteria for abnormal cord gases. Thirty-six of those had umbilical cord milking at delivery. There was no significant difference in neonatal outcomes, but fewer infants in the cord milking group needed resuscitation (38 vs. 56%, p = 0.07) and ongoing respiratory support (19 vs. 31%, p = 0.16) compared to the immediate clamping group.

CONCLUSIONS

While not significant, infants who received cord milking at birth needed less resuscitation and ongoing respiratory support. This study suggests that umbilical cord milking appears to be a safe therapy when acidosis is present and when resuscitation is needed.

Maternal iron metabolism gene variants modify umbilical cord blood lead levels by gene-environment interaction: a birth cohort study

BACKGROUND

Given the relationship between iron metabolism and lead toxicokinetics, we hypothesized that polymorphisms in iron metabolism genes might modify maternal-fetal lead transfer. The objective of this study was to determine whether maternal and/or infant transferrin (TF) and hemochromatosis (HFE) gene missense variants modify the association between maternal blood lead (MBL) and umbilical cord blood lead (UCBL).

METHODS

We studied 476 mother-infant pairs whose archived blood specimens were genotyped for TF P570S, HFE H63D and HFE C282Y. MBL and UCBL were collected within 12 hours of delivery. Linear regression models were used to examine the association between log-transformed MBL and UCBL, examine for confounding and collinearity, and explore gene-environment interactions.

RESULTS

The geometric mean MBL was 0.61 μg/dL (range 0.03, 3.2) and UCBL 0.42 (<0.02, 3.9). Gene variants were common with carrier frequencies ranging from 12-31%; all were in Hardy-Weinberg equilibrium. In an adjusted linear regression model, log MBL was associated with log UCBL (β = 0.92, 95% CI: 0.82, 1.03; p < 0.01) such that a 1% increase in MBL was associated with a 0.92% increase in UCBL among infants born to wild-type mothers. In infants born to C282Y variants, however, a 1% increase in MBL is predicted to increase UCBL 0.65% (β(Main Effect) = -0.002, 95% CI: -0.09, -0.09; p = 0.97; β(Interaction) = -0.27, 95% CI: -0.52, -0.01; p = 0.04), representing a 35% lower placental lead transfer among women with MBL 5 μg/dL.

CONCLUSIONS

Maternal HFE C282Y gene variant status is associated with greater reductions in placental transfer of lead as MBL increases. The inclusion of gene-environment interaction in risk assessment models may improve efforts to safeguard vulnerable populations.

Effect of timing of umbilical cord clamping of term infants on maternal and neonatal outcomes

BACKGROUND

Policies for timing of cord clamping vary, with early cord clamping generally carried out in the first 60 seconds after birth, whereas later cord clamping usually involves clamping the umbilical cord more than one minute after the birth or when cord pulsation has ceased. The benefits and potential harms of each policy are debated.

OBJECTIVES

To determine the effects of early cord clamping compared with late cord clamping after birth on maternal and neonatal outcomes

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (13 February 2013).

SELECTION CRITERIA

Randomised controlled trials comparing early and late cord clamping.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial eligibility and quality and extracted data.

MAIN RESULTS

We included 15 trials involving a total of 3911 women and infant pairs. We judged the trials to have an overall moderate risk of bias. Maternal outcomes: No studies in this review reported on maternal death or on severe maternal morbidity. There were no significant differences between early versus late cord clamping groups for the primary outcome of severe postpartum haemorrhage (risk ratio (RR) 1.04, 95% confidence interval (CI) 0.65 to 1.65; five trials with data for 2066 women with a late clamping event rate (LCER) of ~3.5%, I(2) 0%) or for postpartum haemorrhage of 500 mL or more (RR 1.17 95% CI 0.94 to 1.44; five trials, 2260 women with a LCER of ~12%, I(2) 0%). There were no significant differences between subgroups depending on the use of uterotonic drugs. Mean blood loss was reported in only two trials with data for 1345 women, with no significant differences seen between groups; or for maternal haemoglobin values (mean difference (MD) -0.12 g/dL; 95% CI -0.30 to 0.06, I(2) 0%) at 24 to 72 hours after the birth in three trials. Neonatal outcomes: There were no significant differences between early and late clamping for the primary outcome of neonatal mortality (RR 0.37, 95% CI 0.04 to 3.41, two trials, 381 infants with a LCER of ~1%), or for most other neonatal morbidity outcomes, such as Apgar score less than seven at five minutes or admission to the special care nursery or neonatal intensive care unit. Mean birthweight was significantly higher in the late, compared with early, cord clamping (101 g increase 95% CI 45 to 157, random-effects model, 12 trials, 3139 infants, I(2) 62%). Fewer infants in the early cord clamping group required phototherapy for jaundice than in the late cord clamping group (RR 0.62, 95% CI 0.41 to 0.96, data from seven trials, 2324 infants with a LCER of 4.36%, I(2) 0%). Haemoglobin concentration in infants at 24 to 48 hours was significantly lower in the early cord clamping group (MD -1.49 g/dL, 95% CI -1.78 to -1.21; 884 infants, I(2) 59%). This difference in haemoglobin concentration was not seen at subsequent assessments. However, improvement in iron stores appeared to persist, with infants in the early cord clamping over twice as likely to be iron deficient at three to six months compared with infants whose cord clamping was delayed (RR 2.65 95% CI 1.04 to 6.73, five trials, 1152 infants, I(2) 82%). In the only trial to report longer-term neurodevelopmental outcomes so far, no overall differences between early and late clamping were seen for Ages and Stages Questionnaire scores.

AUTHORS' CONCLUSIONS

A more liberal approach to delaying clamping of the umbilical cord in healthy term infants appears to be warranted, particularly in light of growing evidence that delayed cord clamping increases early haemoglobin concentrations and iron stores in infants. Delayed cord clamping is likely to be beneficial as long as access to treatment for jaundice requiring phototherapy is available.

What do we know of childhood exposures to metals (arsenic, cadmium, lead, and mercury) in emerging market countries?

Arsenic, cadmium, lead, and mercury present potential health risks to children who are exposed through inhalation or ingestion. Emerging Market countries experience rapid industrial development that may coincide with the increased release of these metals into the environment. A literature review was conducted for English language articles from the 21st century on pediatric exposures to arsenic, cadmium, lead, and mercury in the International Monetary Fund's (IMF) top 10 Emerging Market countries: Brazil, China, India, Indonesia, Mexico, Poland, Russia, South Korea, Taiwan, and Turkey. Seventy-six peer-reviewed, published studies on pediatric exposure to metals met the inclusion criteria. The reported concentrations of metals in blood and urine from these studies were generally higher than US reference values, and many studies identified adverse health effects associated with metals exposure. Evidence of exposure to metals in the pediatric population of these Emerging Market countries demonstrates a need for interventions to reduce exposure and efforts to establish country-specific reference values through surveillance or biomonitoring. The findings from review of these 10 countries also suggest the need for country-specific public health policies and clinician education in Emerging Markets.

Optimal timing for clamping the umbilical cord after birth

This article provides a brief overview of pros and cons of clamping the cord too early (within seconds) after birth. It also highlights evolving data that suggest that delaying cord clamping for 30 to 60 seconds after birth is beneficial to the baby, with no measurable negative effects either the baby or the mother.

Long-term child follow-up after large obstetric randomised controlled trials for the evaluation of perinatal interventions: a systematic review of the literature

BACKGROUND

Although the hope is that many perinatal interventions are performed with an ultimate aim to improve the long-term health and development of the child, long-term outcome is rarely used as a primary end-point in perinatal randomised controlled trials (RCTs).

OBJECTIVE

To evaluate how often and with which tools long-term follow-up is performed after large obstetric RCTs.

SEARCH STRATEGY

We searched the Cochrane Library for Cochrane reviews published by the Cochrane Pregnancy and Childbirth Group for reviews on interventions that aimed to improve neonatal outcome. Selection criteria  Reviews on perinatal interventions that were not performed to improve the condition of the neonate were excluded. We limited our review to RCTs with more than 350 participating women. For each included study, we checked in Web of Science as to whether the researchers had reported on follow-up in subsequent publications.

DATA COLLECTION AND ANALYSIS

Relevant information was extracted from these RCTs by two reviewers using a predefined data collection sheet. All information was analysed using SPSS 17.0 (SPSS Inc., Chicago, IL, USA).

MAIN RESULTS

We studied 212 reviews including 1837 RCTs on perinatal interventions, 249 (14%) of which included 350 participants. Only 40 of 249 RCTs (16%) followed the children after discharge from the hospital to evaluate the effect of a specific perinatal intervention. The number of RCTs with long-term follow-up remained stable, with 10 of 67 RCTs (15%) reporting follow-up before 1990, 17 of 115 (15%) between 1990 and 2000, and 13 of 67 (19%) after 2000 (P = 0.68).

CONCLUSIONS

Only a small minority of large perinatal RCTs report the long-term follow-up of the child. Future obstetric RCTs should consider performing long-term follow-up at the start of the trial.

Rethinking placental transfusion and cord clamping issues

A brief delay in clamping the umbilical cord results in a placental transfusion that supplies the infant with a major source of iron during the first few months of life. Cord circulation continues for several minutes after birth and placental transfusion results in approximately 30% more blood volume. Gravity influences the amount of placental transfusion that an infant receives. Placing the infant skin-to-skin requires a longer delay of cord clamping (DCC) than current recommendations. Uterotonics are not contraindicated with DCC. Cord milking is a safe alternative to DCC when one must cut the cord prematurely. Recent randomized controlled trials demonstrate benefits for term and preterm infants from DCC. The belief that DCC causes hyperbilirubinemia or symptomatic polycythemia is unsupported by the available research. Delay of cord clamping substantively increases iron stores in early infancy. Inadequate iron stores in infancy may have an irreversible impact on the developing brain despite oral iron supplementation. Iron deficiency in infancy can lead to neurologic issues in older children including poor school performance, decreased cognitive abilities, and behavioral problems. The management of the umbilical cord in complex situations is inconsistent between birth settings. A change in practice requires collaboration between all types of providers who attend births.

Timing of umbilical cord clamping: effect on iron endowment of the newborn and later iron status

The optimal timing of umbilical cord clamping has been debated in the scientific literature for at least the last century, when cord clamping practices shifted from delayed towards immediate clamping. Recent research provides evidence for the beneficial effect of delayed cord clamping on infant iron status. The present review describes the physiological basis for the impact of cord clamping time on total body iron at birth and the relationship between birth body iron, as affected by cord clamping time, and iron status later in infancy. This research is discussed in the context of current clamping practices, which tend towards early cord clamping in most settings, as well as the high levels of anemia present in young infants in many countries worldwide.

Effect of timing of umbilical cord clamping of term infants on maternal and neonatal outcomes

BACKGROUND

Policies for timing of cord clamping vary, with early cord clamping generally carried out in the first 60 seconds after birth, whereas later cord clamping usually involves clamping the umbilical cord greater than one minute after the birth or when cord pulsation has ceased.

OBJECTIVES

To determine the effects of different policies of timing of cord clamping at delivery of the placenta on maternal and neonatal outcomes.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (December 2007).

SELECTION CRITERIA

Randomised controlled trials comparing early and late cord clamping.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial eligibility and quality and extracted data.

MAIN RESULTS

We included 11 trials of 2989 mothers and their babies. No significant differences between early and late cord clamping were seen for postpartum haemorrhage or severe postpartum haemorrhage in any of the five trials (2236 women) which measured this outcome (relative risk (RR) for postpartum haemorrhage 500 mls or more 1.22, 95% confidence interval (CI) 0.96 to 1.55). For neonatal outcomes, our review showed both benefits and harms for late cord clamping. Following birth, there was a significant increase in infants needing phototherapy for jaundice (RR 0.59, 95% CI 0.38 to 0.92; five trials of 1762 infants) in the late compared with early clamping group. This was accompanied by significant increases in newborn haemoglobin levels in the late cord clamping group compared with early cord clamping (weighted mean difference 2.17 g/dL; 95% CI 0.28 to 4.06; three trials of 671 infants), although this effect did not persist past six months. Infant ferritin levels remained higher in the late clamping group than the early clamping group at six months.

AUTHORS' CONCLUSIONS

One definition of active management includes directions to administer an uterotonic with birth of the anterior shoulder of the baby and to clamp the umbilical cord within 30-60 seconds of birth of the baby (which is not always feasible in practice). In this review delaying clamping of the cord for at least two to three minutes seems not to increase the risk of postpartum haemorrhage. In addition, late cord clamping can be advantageous for the infant by improving iron status which may be of clinical value particularly in infants where access to good nutrition is poor, although delaying clamping increases the risk of jaundice requiring phototherapy.