Identification of neonates at risk for hazardous hyperbilirubinemia: emerging clinical insights

Mother's Own Milk Provision During the First 12 Weeks of Life by Gestational Age

Importance

Although mother's own milk (MOM) is associated with reduced risk of neonatal complications of prematurity and improved neurodevelopmental outcomes, to our knowledge, there have been no large US studies reporting rates of MOM feeding initiation and sustained MOM feedings by gestational age (GA).

Objective

To compare rates of MOM feeding initiation and continuation at 12 weeks for infants by GA.

Design, Setting, and Participants

This retrospective cross-sectional study used state-level surveillance data for maternal characteristics and behaviors before and after pregnancy. Participants were women who gave birth from January 1 through December 31, 2021, in 36 US jurisdictions (33 states, the District of Columbia, New York City, and Puerto Rico) and completed the Pregnancy Risk Assessment Monitoring System (PRAMS) questionnaire. Data were analyzed from July 2023 to April 2024.

Exposure

Infant GA, including early preterm (EPT; ≤27 weeks' gestation), moderately preterm (MPT; 28-33 weeks' gestation), late preterm (LPT; 34-36 weeks' gestation), and early term to postterm (≥37 weeks' gestation).

Main Outcomes and Measures

MOM feeding initiation and continuation at 12 weeks after delivery. Weighted multivariable binary logistic regression models were used to test the association between MOM feeding initiation and continued provision at 12 weeks after delivery by infant GA.

Results

Among 29 098 births, there were 0.4% EPT, 1.8% MPT, 6.7% LPT, and 91.1% early-term to postterm infants. Unadjusted MOM feeding initiation was highest for EPT infants (89.7% [95% CI, 85.0%-94.7%]) and lowest for LPT infants (81.8% [95% CI, 79.5%-84.1%]). For infants that initially received MOM, 71.6% (95% CI, 70.7%-72.6%) of early-term to postterm infants still received MOM at 12 weeks followed by 63.1% (95% CI, 52.9%-73.2%) of EPT infants, 61.2% (95% CI, 58.0%-64.3%) of LPT infants, and 58.6% (95% CI, 53.4%-63.8%) of MPT infants. After adjusting for maternal characteristics, LPT infants were 4.4 (95% CI, -6.7 to -2.1) percentage points less likely to initiate MOM feedings and those who received any MOM were 6.7 (95% CI, -9.9 to -3.5) percentage points less likely to receive MOM at 12 weeks compared with early-term to postterm infants. There were no differences in adjusted initiation or continuation rates among EPT (3.1 [95% CI, -1.4 to 7.5] percentage points for initiation and -0.0 [95% CI, -8.6 to 8.6] percentage points for continuation) or MPT (2.4 [95% CI, -0.5 to 5.3] percentage points for initiation and -3.3 [95% CI, -8.0 to 1.5] percentage points for continuation) infants compared with early-term to postterm infants.

Conclusions and Relevance

This cross-sectional study found that MOM feeding initiation and continuation rates at 12 weeks after birth for LPT infants were substantially lower than rates for infants with other GAs. Research is needed to pinpoint barriers to MOM feeding initiation and continuation in this vulnerable population of infants.

Validating the early phototherapy prediction tool across cohorts

Background

Hyperbilirubinemia of the newborn infant is a common disease worldwide. However, recognized early and treated appropriately, it typically remains innocuous. We recently developed an early phototherapy prediction tool (EPPT) by means of machine learning (ML) utilizing just one bilirubin measurement and few clinical variables. The aim of this study is to test applicability and performance of the EPPT on a new patient cohort from a different population.

Materials and methods

This work is a retrospective study of prospectively recorded neonatal data from infants born in 2018 in an academic hospital, Regensburg, Germany, meeting the following inclusion criteria: born with 34 completed weeks of gestation or more, at least two total serum bilirubin (TSB) measurement prior to phototherapy. First, the original EPPT-an ensemble of a logistic regression and a random forest-was used in its freely accessible version and evaluated in terms of the area under the receiver operating characteristic curve (AUROC). Second, a new version of the EPPT model was re-trained on the data from the new cohort. Third, the predictive performance, variable importance, sensitivity and specificity were analyzed and compared across the original and re-trained models.

Results

In total, 1,109 neonates were included with a median (IQR) gestational age of 38.4 (36.6-39.9) and a total of 3,940 bilirubin measurements prior to any phototherapy treatment, which was required in 154 neonates (13.9%). For the phototherapy treatment prediction, the original EPPT achieved a predictive performance of 84.6% AUROC on the new cohort. After re-training the model on a subset of the new dataset, 88.8% AUROC was achieved as evaluated by cross validation. The same five variables as for the original model were found to be most important for the prediction on the new cohort, namely gestational age at birth, birth weight, bilirubin to weight ratio, hours since birth, bilirubin value.

Discussion

The individual risk for treatment requirement in neonatal hyperbilirubinemia is robustly predictable in different patient cohorts with a previously developed ML tool (EPPT) demanding just one TSB value and only four clinical parameters. Further prospective validation studies are needed to develop an effective and safe clinical decision support system.

Fatal Hypernatremic Dehydration in a Term Exclusively Breastfed Newborn

Hypernatremic dehydration in term newborns has steadily increased in incidence with increasing efforts to promote exclusive breastfeeding before hospital discharge, a key metric of the Baby-Friendly Hospital Initiative. The following report details a case of a term newborn infant who had evidence of poor intake while exclusively breastfeeding during his hospital stay that may not have been recognized by health care providers. The infant was discharged home and was subsequently found by the parents in cardiac arrest 12 h after discharge and was found to have hypernatremic dehydration. Although return of spontaneous circulation was achieved after fluid resuscitation, the infant sustained extensive hypoxic-ischemic brain injury due to cardiovascular collapse. Due to the infant’s extremely poor prognosis, life support was withdrawn at 19 days of age and the infant expired. This sentinel case demonstrates multiple pitfalls of current perceptions of normal vs. abnormal newborn feeding behavior, weight loss percentages, elimination patterns, and acceptable clinical thresholds believed to be safe for neonates. Newer data have shown that hypernatremia occurs commonly in healthy, term breastfed newborns at weight loss percentages previously deemed normal by most health professionals and hospital protocols. In-hospital strategies to prevent excessive weight loss and screening for hypernatremia in response to signs of inadequate feeding have the potential to prevent tens of thousands of readmissions for feeding complications a year, as well as hundreds of millions in health care costs.

Sixth-Hour Trancutaneous Bilirubin and Need for Phototherapy in DAT Positive Newborns

OBJECTIVES

To characterize the outcomes of ABO incompatible direct antiglobulin test (DAT) positive newborns and determine the predictive ability of a sixth-hour transcutaneous bilirubin (TcB for needing phototherapy ≤24 hours of age.

METHODS

Retrospective, cross-sectional study from May 2013 to March 2017. Of 10 942 consecutive newborns ≥35 weeks estimated gestational age, 829 were ABO incompatible and DAT positive. After excluding for antibodies other than ABO (51), missing data (4), miscategorization of blood type O (1), and duplicate record (1), 772 newborns remained. Of 772, a subsample of 346 newborns with both TcB and total serum bilirubin (TSB) tests within 1 hour of the sixth hour was analyzed to determine the predictive ability.

RESULTS

Phototherapy was required in 281 of 772 (36.4%); 156 (20.2%) in the first 24 hours. There were 10 (1.3%) admissions for hyperbilirubinemia to the NICU for intravenous immunoglobin. Birth weight, infant blood type B, TSB, reticulocyte count, and TcB were all significantly associated with phototherapy ≤24 hours. On multivariate analysis, significant predictors of phototherapy ≤24 hours were TSB and reticulocyte count if no TcB was done and TcB alone if no blood tests were done. TcB was highly predictive (odds ratio 3.1, 95% confidence interval: 2.4-4.0) and nearly as accurate as the TSB and reticulocyte count (area under the curve, 0.90 and 0.96, respectively). Low (<3.0 mg/dL) and high (≥5.3 mg/dL) risk TcB cutoffs demonstrated a negative predictive value of 98% and positive predictive value of 85%, respectively.

CONCLUSIONS

Among high-risk ABO incompatible DAT positive newborns, the sixth-hour TcB is highly predictive of the need for phototherapy ≤24 hours.

Etiology and therapeutic management of neonatal jaundice in Iran: a systematic review and meta-analysis

BACKGROUND

Jaundice is a life-threatening disorder in the neonates. In the present study, we aimed to assess systematically available evidence on causes and management of jaundice in Iranian newborn patients.

METHODS

We searched the databases of PubMed, Web of Sciences, Scopus and Google Scholar for English articles published since inception until May 2019. A search was also done for Persian articles in Magiran and Scientific Information Database. Studies were evaluated based on predefined criteria by two reviewers. Data analysis was performed by STATA software.

RESULTS

A total of 33 articles were finally included. The overall pooled prevalence of causes of jaundice among Iranian neonates was as follows: ABO blood groups incompatibility, 16.9% [95% confidence interval (CI) 10.9-22.8]; Rh blood group incompatibility, 4% (95% CI 2.5-5.5); ABO and Rh blood groups incompatibility, 3.6% (95% CI 0-7.7); glucose-6-phosphate dehydrogenase (G6PD) deficiency, 6.3% (95% CI 5.1-7.5); infection, 6.6% (95% CI 5.2-8.1); hypothyroidism, 4.2% (95% CI 0.1-8.3); infant of diabetic mother: 2.3% (95% CI 0.1-4.5); unknown, 50.7% (95% CI 33.4-68); cephalohematoma, 0.6% (95% CI 0.3-0.9). Regarding treatment of icterus, seven and eight articles were found on phototherapy and exchange transfusion, respectively. In five studies, all patients underwent phototherapy, but rate of exchange transfusion use was between 6.6% and 50.9%.

CONCLUSIONS

According to the results, unknown factors were the most common causes of icterus in Iranian neonates, followed by ABO blood groups incompatibility, infections and G6PD deficiency. By the way, phototherapy and exchange transfusion were found as therapeutic choices of neonatal jaundice.

Baby-Friendly Hospital Initiative Is Associated with Lower Rates of Neonatal Hyperbilirubinemia

Background: The Baby-Friendly Hospital Initiative (BFHI) advances practices that support exclusive breastfeeding. BFHI practices are associated with increased breastfeeding rates, however, other patient outcomes are not well described. This study examined the association of BFHI practices with hyperbilirubinemia and phototherapy between groups of newborns born before and after BFHI implementation at an urban, tertiary academic medical center in South Carolina. Materials and Methods: We conducted a retrospective study of healthy, term newborns born between July and September 2011 (n = 956), before BFHI implementation, and newborns born during the same period in 2013 (n = 1,131) after BFHI implementation. Primary outcomes were neonatal hyperbilirubinemia, phototherapy treatment, and hospital readmissions for hyperbilirubinemia within 30 days of discharge. We compared rates of outcomes between the study groups using unadjusted and adjusted odds ratios (OR). Results: Among newborns born before versus after BFHI implementation, 20.3% versus 6.98% were diagnosed with hyperbilirubinemia (p < 0.001), 5.75% versus 1.95% received phototherapy (p < 0.001), and 0.31% versus 0.35% were readmitted to the hospital for hyperbilirubinemia within 30 days (p = 0.88). In adjusted analyses, newborns born after BFHI implementation were significantly less likely to develop neonatal hyperbilirubinemia (OR 0.28 [95% confidence intervals; CI 0.20-0.37]) and receive phototherapy treatment (OR 0.27 [95% CI 0.15-0.49]) than newborns born before BFHI implementation. Conclusions: Implementation of BFHI practices is associated with significant decreases in neonatal hyperbilirubinemia and phototherapy without affecting readmission rates. Exclusive breastfeeding has traditionally been considered a risk factor for the development of neonatal jaundice. This study demonstrates that BFHI practices may mitigate that risk.

Elective Deliveries and Neonatal Outcomes in Full-Term Pregnancies

Cesarean and induced delivery rates have risen substantially in recent decades and currently account for over one-third and one-fourth of US births, respectively. Initiatives to encourage delaying deliveries until a gestational age of 39 weeks appear to have slowed the increases but have not led to declines. The rates are at historic highs and the consequences of these interventions when not medically necessary have not been systematically explored at the population level. In this study, we used population-level data on births in New Jersey (1997-2011) to document trends in elective deliveries (induced vaginal delivery, cesarean delivery with no labor trial, and cesarean delivery after induction) and estimate logistic and linear regression models of associations between delivery method and neonatal morbidities and cost-related outcomes in low-risk pregnancies. We found that elective deliveries more than doubled during the observation period and were associated with neonatal morbidities and cost-related outcomes even at gestational ages of 39 and 40 weeks. Findings suggest that delaying beyond 39 weeks and avoiding delivery interventions when not medically necessary would improve infant health and reduce health-care costs.

Humanized UGT1 Mice, Regulation of UGT1A1, and the Role of the Intestinal Tract in Neonatal Hyperbilirubinemia and Breast Milk-Induced Jaundice

Neonatal hyperbilirubinemia and the onset of bilirubin encephalopathy and kernicterus result in part from delayed expression of UDP-glucuronosyltransferase 1A1 (UGT1A1) and the ability to metabolize bilirubin. It is generally believed that acute neonatal forms of hyperbilirubinemia develop due to an inability of hepatic UGT1A1 to metabolize efficiently bilirubin for clearance through the hepatobiliary tract. Newly developed mouse models designed to study bilirubin metabolism have led to new insight into the role of the intestinal tract in controlling neonatal hyperbilirubinemia. Humanization of mice with the UGT1 locus (hUGT1 mice) and the UGT1A1 gene provide a unique tool to study the onset of hyperbilirubinemia since the human UGT1A1 gene is developmentally regulated during the neonatal period in hUGT1 mice. A new mechanism outlying developmental expression of intestinal UGT1A1 is presented and its implications in the control of neonatal hyperbilirubinemia discussed. New findings linking breast milk protection against necrotizing enterocolitis and intestinal control of UGT1A1 may help explain the contribution of breast milk toward the development of neonatal hyperbilirubinemia. Our findings outline a new model that includes an active intestinal ROS /IκB kinase/nuclear receptor corepressor 1 loop that can be applied to an understanding of breast milk-induced jaundice.

Risk Factors Associated with Neonatal Jaundice: A Cross-Sectional Study from Iran

BACKGROUND

Neonatal jaundice is one of the main causes of the patient's admission in the neonatal period and is potentially linked to morbidity.

AIM

This study aimed to determine the possible risk factors for neonatal jaundice.

METHODS

We investigated the case of infants who were admitted to the neonatal department of Ziyaeian hospital and Imam Khomeini Hospital for jaundice. Simple random sampling was used to evaluate variables related to maternal and neonatal predisposing factors based on the medical records and clinical profiles. All variables in this study were analysed using SPSS software.

RESULTS

In this study, about 200 mothers and neonates were examined. Our findings depicted that mother's WBC, Hb, PLT, and gestational age were associated with jaundice (P < 0.05). Furthermore, there were significant relationships between different degrees of bilirubin with TSH, T4 levels and G6PD (P < 0.05). In fact, TSH, T4 levels and G6PD were found to be linked to neonatal hyperbilirubinemia. The risk factors for jaundice in our study population comprise some predisposing factors such as WBC, Hb, PLT, gestational age, TSH, and T4 levels, as well as G6PD. Neonates at risk of jaundice are linked to some maternal and neonatal factors that can provide necessary interventions to reduce the burden of the disease. Therefore, identification of associated factors can facilitate early diagnosis, and reduce subsequent complications.

CONCLUSION

Neonatal jaundice should be considered as the main policy in all health care settings of the country. Therefore, identification of factors affecting the incidence of jaundice can be effective in preventing susceptible predisposing factors in newborns and high-risk mothers.

Maternal risk factors for neonatal jaundice: a hospital-based cross-sectional study in Tehran

Diagnosis and timely treatment of neonatal jaundice is critical to preventing its dangerous side effects. Knowing the predisposing factors of neonatal jaundice is still a serious debate, which can be effective in controlling jaundice and the primary problem. The aim of this study was to evaluate maternal risk factors that contribute to the Hyperbilirubinemia among newborns admitted to Imam Khomeini and Ziaeean hospitals during 2015. We collected random samplings for the current study. Medical records for all newborns with jaundice were examined for risk factors associated with Hyperbilirubinemia. All variables were analyzed by SPSS software, version 19. Chi-square test and T-test were applied to evaluate qualitative and quantitative data, respectively. Our findings revealed that maternal age, weight, BMI, WBC, Hb, PLT, birth in the first pregnancy, numbers of pregnancies and prolonged delivery were significantly associated with bilirubin levels. Preventing the risk correlated with maternal factors or identifying neonates with these risk factors is important in effective management of infants. Therefore, the evaluation of neonatal jaundice in health care services should always be considered as a fundamental policy.

Correlation between serum vitamin D level and neonatal indirect hyperbilirubinemia

BACKGROUND

Considering the significant prevalence of Neonatal Indirect Hyperbilirubinemia (NIH) and its irreversible neurological complications, identifying the factors involved in the prevalence of neonatal jaundice is essential. The present study was conducted to determine the relationship between serum vitamin D levels and the prevalence of NIH in infants admitted to Qods Hospital of Qazvin in Iran in 2015-16.

METHODS

In this case-control study, 30 term infants with NIH (the case group) were compared with 30 healthy, non- icteric, term infants (the control group) in terms of serum levels of 25-hydroxyvitamin D. The results were analyzed and compared between the two groups using t-test and the Chi-square test.

RESULTS

The mean and standard deviation of serum 25-hydroxyvitamin D levels were 10.76 ± 8.6 ng/dl in the case group and 14.88 ± 11.38 ng/dl in the control group. There were no significant differences between the two groups (P = 0.11).

CONCLUSION

The results suggest the lack of a relationship between vitamin D levels and NIH. However, further prospective studies are needed to conclude that vitamin D has no role in the pathogenesis of NIH.

Effects of massage on newborn infants with jaundice: A meta-analysis

Objective

This meta-analysis aims to systematically evaluate the effects of massage on infants with jaundice.

Methods

Multiple electronic databases, including Cochrane Library, PubMed, EMBASE, Web of Science, China Biology Medicine (CBM), Wan Fang Data, VIP Database for Chinese Technical Periodicals and China National Knowledge Infrastructure (CNKI), were used to search for studies on the effects of massage on infants with jaundice. Data were analysed by Rev Man 5.3.

Results

A total of 14 randomised controlled trials with 1889 patients were included. Statistically significant difference in percutaneous bilirubin [MD = −1.21, 95% CI (−1.90, −0.52), P < 0.05; MD = −2.00, 95% CI (−2.68, −1.32), P < 0.05; MD = −2.00, 95% CI (2.56, −1.44), P < 0.05; MD = −1.93, 95% CI (−2.44, −1.43), P < 0.05] was found between two groups at 48, 72, 96 and 168 h. Studies on the serum total bilirubin level were divided into two subgroups according to sample size, and the results of subgroup analysis showed that the serum total bilirubin level in the intervention group was significantly lower than that in the control group [MD = −52.06, 95% CI (−57.76, −46.36), P < 0.05 and MD = −10.65, 95% CI (−14.66, −6.63), P < 0.05]. Statistically significant difference in defecation frequency was observed between the two groups at 48 h after birth[SMD = 0.44, 95%CI (0.02, 0.87), P < 0.05].

Conclusion

Massage can decrease serum total bilirubin and percutaneous bilirubin levels and increasing defecation frequency. However, due to heterogeneity among studies, numerous multi-centre, large-sample and high-quality randomised controlled trials are needed to verify the effects of massage.

Intestinal NCoR1, a regulator of epithelial cell maturation, controls neonatal hyperbilirubinemia

Severe neonatal hyperbilirubinemia (SNH) and the onset of bilirubin encephalopathy and kernicterus result in part from delayed expression of UDP-glucuronosyltransferase 1A1 (UGT1A1) and the inability to metabolize bilirubin. Although there is a good understanding of the early events after birth that lead to the rapid increase in serum bilirubin, the events that control delayed expression of UGT1A1 during development remain a mystery. Humanized UGT1 (hUGT1) mice develop SNH spontaneously, which is linked to repression of both liver and intestinal UGT1A1. In this study, we report that deletion of intestinal nuclear receptor corepressor 1 (NCoR1) completely diminishes hyperbilirubinemia in hUGT1 neonates because of intestinal UGT1A1 gene derepression. Transcriptomic studies and immunohistochemistry analysis demonstrate that NCoR1 plays a major role in repressing developmental maturation of the intestines. Derepression is marked by accelerated metabolic and oxidative phosphorylation, drug metabolism, fatty acid metabolism, and intestinal maturation, events that are controlled predominantly by H3K27 acetylation. The control of NCoR1 function and derepression is linked to IKKβ function, as validated in hUGT1 mice with targeted deletion of intestinal IKKβ. Physiological events during neonatal development that target activation of an IKKβ/NCoR1 loop in intestinal epithelial cells lead to derepression of genes involved in intestinal maturation and bilirubin detoxification. These findings provide a mechanism of NCoR1 in intestinal homeostasis during development and provide a key link to those events that control developmental repression of UGT1A1 and hyperbilirubinemia.

Moderate Hyperbilirubinemia Alters Neonatal Cardiorespiratory Control and Induces Inflammation in the Nucleus Tractus Solitarius

Hyperbilirubinemia (HB) occurs in 90% of preterm newborns. Moderate HB can induce acute neurological disorders while severe HB has been linked to a higher incidence of apneas of prematurity. The present study aimed to test the hypothesis that even moderate HB disrupts cardiorespiratory control in preterm lambs. Two groups of preterm lambs (born 14 days prior to term), namely control (n = 6) and HB (n = 5), were studied. At day 5 of life, moderate HB (150–250 μmol/L) was induced during 17 h in the HB group after which cardiorespiratory control as well as laryngeal and pulmonary chemoreflexes were assessed during baseline recordings and during hypoxia. Recordings were repeated 72 h after HB induction, just before euthanasia. In addition, neuropathological studies were performed to investigate for cerebral bilirubin deposition as well as for signs of glial reactivity in brainstem structures involved in cardiorespiratory control. Results revealed that sustained and moderate HB: (i) decreased baseline respiratory rate and increased the time spent in apnea; (ii) blunted the cardiorespiratory inhibition normally observed during both laryngeal and pulmonary chemoreflexes; and (iii) increased heart rate in response to acute hypoxia. These acute physiological changes were concurrent with an activation of Alzheimer type II astrocytes throughout the brain, including the brainstem. Concomitantly, bilirubin deposits were observed in the leptomeninges, but not in brain parenchyma. While most cardiorespiratory alterations returned to normal 72 h after HB normalization, the expression of glial fibrillary acid protein (GFAP) and ionized calcium binding adaptor molecule 1 (Iba1) was still increased within the nucleus tractus solitarius. In conclusion, moderate and sustained HB in preterm lambs induced cardiorespiratory alterations, the latter of which were associated with neurohistopathological changes. These changes are indicative of an inflammatory response in the brainstem neuroanatomical substrates involved in cardiorespiratory control.

Glucose-6-Phosphate Dehydrogenase Deficiency and the Need for a Novel Treatment to Prevent Kernicterus

Hyperbilirubinemia occurs frequently in newborns, and in severe cases can progress to kernicterus and permanent developmental disorders. Glucose-6-phosphate dehydrogenase (G6PD) deficiency, one of the most common human enzymopathies, is a major risk factor for hyperbilirubinemia and greatly increases the risk of kernicterus even in the developed world. Therefore, a novel treatment for kernicterus is needed, especially for G6PD-deficient newborns. Oxidative stress is a hallmark of bilirubin toxicity in the brain. We propose that the activation of G6PD via a small molecule chaperone is a potential strategy to increase endogenous defense against bilirubin-induced oxidative stress and prevent kernicterus.

Post-test probability for neonatal hyperbilirubinemia based on umbilical cord blood bilirubin, direct antiglobulin test, and ABO compatibility results

Many hospitals opt for early postnatal discharge of newborns with a potential risk of readmission for neonatal hyperbilirubinemia. Assays/algorithms with the possibility to improve prediction of significant neonatal hyperbilirubinemia are needed to optimize screening protocols and safe discharge of neonates. This study investigated the predictive value of umbilical cord blood (UCB) testing for significant hyperbilirubinemia. Neonatal UCB bilirubin, UCB direct antiglobulin test (DAT), and blood group were determined, as well as the maternal blood group and the red blood cell antibody status. Moreover, in newborns with clinically apparent jaundice after visual assessment, plasma total bilirubin (TB) was measured. Clinical factors positively associated with UCB bilirubin were ABO incompatibility, positive DAT, presence of maternal red cell antibodies, alarming visual assessment and significant hyperbilirubinemia in the first 6 days of life. UCB bilirubin performed clinically well with an area under the receiver-operating characteristic curve (AUC) of 0.82 (95 % CI 0.80-0.84). The combined UCB bilirubin, DAT, and blood group analysis outperformed results of these parameters considered separately to detect significant hyperbilirubinemia and correlated exponentially with hyperbilirubinemia post-test probability.

CONCLUSION

Post-test probabilities for neonatal hyperbilirubinemia can be calculated using exponential functions defined by UCB bilirubin, DAT, and ABO compatibility results.

WHAT IS KNOWN

• The diagnostic value of the triad umbilical cord blood bilirubin measurement, direct antiglobulin testing and blood group analysis for neonatal hyperbilirubinemia remains unclear in literature. • Currently no guideline recommends screening for hyperbilirubinemia using umbilical cord blood. What is New: • Post-test probability for hyperbilirubinemia correlated exponentially with umbilical cord blood bilirubin in different risk groups defined by direct antiglobulin test and ABO blood group compatibility results. • Exponential functions can be used to calculate hyperbilirubinemia probability.

Pediatric Provider Insight Into Newborn Screening for Glucose-6-Phosphate Dehydrogenase Deficiency

OBJECTIVE

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a major contributor to neonatal hyperbilirubinemia, yet newborn screening for this disorder in the United States is not standard practice. We surveyed pediatric providers regarding a novel newborn G6PD screening program successfully implemented in 2007 at a US urban women's hospital newborn nursery.

STUDY DESIGN

An electronic survey was distributed to 472 pediatric providers addressing extent to which they were influenced by the screening program.

RESULTS

Ninety-two (20%) providers responded, of whom 74 (80%) had taken care of G6PD-deficient patients diagnosed by the screening program. A majority found the diagnosis helpful for patient management and influential in their management. Most common changes in management included more counseling on jaundice and follow-up and avoidance of hemolytic crisis triggers.

CONCLUSIONS

General pediatric providers support newborn G6PD screening and appreciate the current program. Knowing the G6PD deficiency status of newborns informed and influenced pediatric providers' care.

Effects of Moderate Hyperbilirubinemia on Nutritive Swallowing and Swallowing-Breathing Coordination in Preterm Lambs

BACKGROUND

Hyperbilirubinemia (HB) occurs in 90% of preterm newborns. HB induces acute neurological disorders (somnolence, abnormal tone, feeding difficulties, auditory dysfunction) and alterations in respiratory control. These findings suggest brainstem neurotoxicity that could also affect swallowing centers.

OBJECTIVE

To test the hypothesis that HB impairs nutritive swallowing (NS) and swallowing-breathing coordination.

METHODS

Two groups of preterm lambs (born 14 days prior to term), namely control (n = 6) and HB (n = 5), were studied. On day 5 of life (D0), moderate HB (150-250 µmol/l) was induced during 17 h in the HB group. Swallowing was assessed via recording of pharyngeal pressure and respiration by respiratory inductance plethysmography and pulse oximetry. The effect of HB on NS was assessed during standardized bottle-feeding. A second recording was performed 48 h after recovery from HB (D3).

RESULTS

Swallows were less frequent (p = 0.003) and of smaller volume (p = 0.01) in HB lambs while swallowing frequency was decreased (p = 0.004). These differences disappeared after HB normalization. Swallowing-breathing coordination was impaired in HB lambs, with a decrease in percent time with NS burst-related apneas/hypopneas at D0 and D3. Simultaneously, HB lambs tended to experience more severe desaturations (<80%) during bottle-feeding. Finally, following bottle-feeding, the respiratory rate was significantly lower, along with an increased apnea duration in HB lambs.

CONCLUSIONS

Swallowing and swallowing-breathing coordination are altered by acute moderate HB in preterm lambs. Decreased efficiency at bottle-feeding is accompanied by continuation of breathing during swallow bursts, which may promote lung aspiration.

Late-preterm birth and neonatal morbidities: population-level and within-family estimates

PURPOSE

The objective of this study was to compare two salient neonatal outcomes-respiratory disorders and hyperbilirubinemia-between late-preterm (34-36 weeks) and full-term (37-41 weeks) singleton infants both at the population level and within families.

METHODS

Analyses were based on natality data on all births in the state of New Jersey from 1996 to 2006 linked to newborn hospital discharge records. For population-level models, logistic regression analyses were conducted to estimate unadjusted and adjusted differences in outcomes by gestational age. For within-family analyses, unadjusted and adjusted logistic fixed-effects models were estimated with the latter including factors that differed across births to the same mother.

RESULTS

Late-preterm birth increased the odds of a neonatal respiratory condition by more than fourfold (odds ratio, 4.08-4.53) and of neonatal hyperbilirubinemia by more than fivefold (odds ratio, 5.11-5.93) even when comparing births to the same mother and controlling for demographic and economic, behavioral, and obstetric factors that may have changed across pregnancies.

CONCLUSIONS

Based on population-level and within-family models, this study provides the strongest evidence to date that late-preterm birth is an important risk factor for adverse neonatal outcomes that other studies have found are associated with cognitive and behavioral disorders in childhood.

Sixth hour transcutaneous bilirubin predicting significant hyperbilirubinemia in ABO incompatible neonates

BACKGROUND

Neonates with ABO hemolytic disease are at greater risk for developing significant hyperbilirubinemia. We aimed to determine whether sixth hour transcutaneous bilirubin (TcB) could predict such a risk.

METHODS

TcB measurements were obtained at the 6th hour of life in blood group A or B neonates born to blood group O, rhesus factor compatible mothers. Subsequent hyperbilirubinemia was monitored and considered significant if a neonate required phototherapy/exchange transfusion. The predictive role of sixth hour TcB was estimated.

RESULTS

Of 144 ABO incompatible neonates, 41(OA, 24; O-B, 17) had significant hyperbilirubinemia. Mean sixth hour TcB was significantly higher among neonates who developed significant hyperbilirubinemia than those who did not (5.83±1.35 mg/dL vs. 3.65±0.96 mg/dL, P<0.001). Sixth hour TcB value >4 mg/dL had the highest sensitivity of 93.5% and >6 mg/dL had the highest specificity of 99%. Area under receiver operating characteristic curve was 0.898.

CONCLUSION

Sixth hour TcB predicts subsequent significant hyperbilirubinemia in ABO incompatible neonates.

Impact of fatty acids on human UDP-glucuronosyltransferase 1A1 activity and its expression in neonatal hyperbilirubinemia

While breast milk has been known as a cause of neonatal hyperbilirubinemia, the underlying mechanism of breast milk-induced jaundice has not been clarified. Here, the impact of fatty acids on human UDP-glucuronosyltransferase (UGT) 1A1--the sole enzyme that can metabolize bilirubin--were examined. Oleic acid, linoleic acid, and docosahexaenoic acid (DHA) strongly inhibited UGT1A1 activity. Forty-eight hours after a treatment with a lower concentration of DHA (10 mg/kg), total bilirubin significantly increased in neonatal hUGT1 mice, which are human neonatal jaundice models. In contrast, treatments with higher concentrations of fatty acids (0.1-10 g/kg) resulted in a decrease in serum bilirubin in hUGT1 mice. It was further demonstrated that the treatment with higher concentrations of fatty acids induced UGT1A1, possibly by activation of peroxisome proliferator-activated receptors. Our data indicates that activation of peroxisome proliferator-activated receptors would increase UGT1A1 expression, resulting in reduction of serum bilirubin levels in human infants.

Incidence of and risk factors for neonatal jaundice among newborns in southern Nepal

OBJECTIVE

To quantify the incidence of and risk factors for neonatal jaundice among infants referred for care from a rural, low-resource, population-based cohort in southern Nepal.

METHODS

Study participants were 18,985 newborn infants born in Sarlahi District in southern Nepal from May 2003 through January 2006 who participated in a cluster-randomised, placebo-controlled, community-based trial to evaluate the effect of newborn chlorhexidine cleansing on neonatal mortality and morbidity. Jaundice was assessed based on visual assessment of the infant by a study worker and referral for care. Adjusted relative risks (RR) were estimated to identify risk factors for referral for neonatal jaundice using Poisson regression.

RESULTS

The incidence of referral for neonatal jaundice was 29.3 per 1000 live births (95% confidence interval: 26.9, 31.7). Male sex, high birth weight, breastfeeding patterns, warm air temperature, primiparity, skilled birth attendance, place of delivery, prolonged labour, oil massage, paternal education and ethnicity were significant risk factors (P-values < 0.01). After multivariable adjustment, sex, birth weight, difficulty feeding, prolonged labour, primiparity, oil massage, ambient air temperature and ethnicity remained important factors. Among infants with difficulty feeding, exclusive breastfeeding was a risk factor for neonatal jaundice, whereas exclusive breastfeeding was protective among infants with no report of difficulty feeding.

CONCLUSIONS

Several known risk factors for neonatal jaundice in a low-resource setting were confirmed in this study. Unique observed associations of jaundice with ambient air temperature and oil massage may be explained by the opportunity for phototherapy based on the cultural practices of this study population. Future research should investigate the role of an infant's difficulty in feeding as a potential modifier in the association between exclusive breastfeeding and jaundice.

Trends of transcutaneous bilirubin in neonates who develop significant hyperbilirubinemia

OBJECTIVES

To provide data on the natural course of transcutaneous bilirubin (TcB) levels in neonates before the development of significant hyperbilirubinemia, and to assess the effect of different demographic and perinatal factors on the rate of TcB increase.

METHODS

We analyzed 2454 TcB measurements from 419 neonates before the development of significant hyperbilirubinemia. Mean TcB values and TcB percentiles for designated times were calculated, and the effect of different risk factors on the rate of TcB increase was assessed. TcB percentile curves were plotted for comparison on a population-based TcB nomogram.

RESULTS

Blood incompatibilities and glucose-6-phosphate dehy-drogenase deficiency were associated with higher rates of TcB in-crease during the first 36 to 48 postnatal hours, whereas smaller gestational age, increased weight loss, and exclusive breastfeeding had a similar but later effect. Compared with general population norms, a different pattern of TcB increase was noted in neonates who developed significant hyperbilirubinemia, but with a sub-stantial overlap of TcB values during the first 24 to 48 postnatal hours.

CONCLUSIONS

We provide data on the natural course of TcB levels before the development of significant hyperbilirubinemia in a white population of term and near-term neonates. Smaller gestational age, blood incompatibilities, glucose-6-phosphate dehydrogenase deficiency, increased weight loss, and exclusive breastfeeding significantly affected the rate of TcB increase in a time-dependent manner. These findings may assist in assessing the risk for significant hyperbilirubinemia and planning appropriate follow-up strategies for neonates with borderline bilirubin levels.

Predischarge non-invasive risk assessment for prediction of significant hyperbilirubinemia in term and late preterm neonates

OBJECTIVE

To evaluate efficacy of predischarge transcutaneous bilirubin (TcB) measurement and clinical risk assessment in predicting hyperbilirubinemia needing treatment.

STUDY DESIGN

A diagnostic test was performed in a prospective cohort study conducted at a teaching hospital in North India. Subjects included healthy neonates with a gestation period of ≥35 weeks or birth weight ≥2000 g. Maternal, neonatal and delivery risk factors for hyperbilirubinemia were prospectively collected. TcB was measured in all enrolled neonates at 24±6, 72 to 96 and 96 to 144 h of postnatal age and when indicated clinically. Neonates were followed up during hospital stay and after discharge till completion of the 7th postnatal day. The key outcome was significant hyperbilirubinemia defined as need of phototherapy on the basis of modified American Academy of Pediatrics guidelines. In neonates born at ≥38 weeks of gestation and in neonates born at ≤37 completed weeks of gestation, middle line and lower line of phototherapy thresholds were used to initiate phototherapy, respectively. Variables observed to be significantly associated with significant hyperbilirubinemia on multivariate analysis were used for construction of a clinical risk assessment tool. Predictive ability of the risk assessment tool was assessed by calculating sensitivity, specificity, positive predictive value and negative predictive value, by plotting receiver-operating characteristics curve and calculating c-statistic.

RESULT

A total of 997 neonates (birth weight: 2627±536 g, gestation: 37.8±1.5 weeks) were enrolled in the study, of which 931 completed follow-up. Among enrolled neonates, 344 (34.5%) were low birth weight. Overall, a total of 199 (20%) neonates developed significant hyperbilirubinemia. On stepwise logistic regression analysis, predischarge TcB percentile and gestation were significantly found to be associated with significant hyperbilirubinemia. A risk assessment graph was constructed to predict subsequent development of significant hyperbilirubinemia. Area under curve for this risk assessment strategy was 0.75.

CONCLUSION

A risk assessment graphical tool consisting of TcB and gestation accurately predicted subsequent need of phototherapy. Further studies are needed to validate performance of this risk assessment tool.

Newborn clinical outcomes of the AWHONN late preterm infant research-based practice project

OBJECTIVE

To describe the neonatal health risks (hypothermia, hypoglycemia, hyperbilirubinemia, respiratory distress, the need for a septic workup, and feeding difficulties) experienced by late preterm infants (LPIs) from a large multisite study and determine how these risks were affected by gestational age at birth.

DESIGN

Descriptive analysis of prospective data obtained as part of the AWHONN Late Preterm Infant Research-Based Practice Project.

SETTING

Fourteen hospitals located through the United States and Canada.

PARTICIPANTS

Late preterm infants (802) born at gestational ages between 34 0/7 and 36 6/7 weeks.

METHODS

Nurses at each site obtained consent from the mother of the infant. The data about the infant were gathered from the infant's medical record.

RESULTS

Thirty-six percent of LPIs were initially cared for in a special care nursery; approximately one half of these infants were eventually transferred to a well-baby nursery. Of the 64% of LPIs initially cared for in a routine nursery, 10% were transferred to a special care unit or neonatal intensive care unit (NICU). More than one half of LPIs experienced hypothermia, hypoglycemia, feeding difficulties, hyperbilirubinemia, and respiratory distress and/or needed a septic workup. The risk for these problems was higher in infants of younger gestational ages. Thirty-two percent of the infants were bathed during the first 2 hours of life, and by 4 hours, more than two thirds had had their first bath. Fifty-two percent received kangaroo care during the first 48 hours of life.

CONCLUSION

These findings support those of smaller studies indicating that LPIs are at high risk for developing health problems during their neonatal hospitalization. Nurses may be able to ameliorate some of these health problems through early identification of problems and simple, inexpensive interventions such as avoiding early bathing and promoting kangaroo care.

Risk factors for hyperbilirubinemia in breastfed term neonates

Increased breastfeeding was suggested as a contributing factor to significant hyperbilirubinemia. The aim of this study was to identify the risk factors associated with jaundice in exclusively breastfed term neonates. We retrospectively reviewed all consecutively live-born neonates from August 2009 to July 2010 who had complete outpatient department (OPD) follow-up at ≤14 days old. Hyperbilirubinemia was defined as a transcutaneous bilirubin (TcB) value of ≥15 mg/dl. During the study period, there were 718 deliveries, of which 152 neonates were transferred to the special care nursery or neonatal intensive care unit; 566 neonates were discharged from the nursery, and 243 neonates were excluded: 83 did not return to the OPD, 46 were older than 14 days at OPD follow-up, 44 were <37 weeks of gestational age, and 70 had been fed formula. In total, 323 neonates were enrolled and classified into the hyperbilirubinemic (114 neonates) and non-hyperbilirubinemic groups (209 neonates). The gender, gestational age, Apgar score, age at nursery discharge, birth weight, and body weight at nursery discharge and at OPD were comparable between the two groups. TcB values at nursery discharge were positively correlated with TcB values in the OPD. Infants with hyperbilirubinemia exhibited significantly greater body weight loss from birth to the OPD follow-up and significantly less body weight gain from nursery discharge to OPD follow-up.

CONCLUSION

High TcB values at nursery discharge and a smaller body weight gain are associated with hyperbilirubinemia in term neonates who are exclusively breastfed.

Hyperbilirubinemia in the newborn

After completing this article, readers should be able to: 1. List the risk factors for severe hyperbilirubinemia. 2. Distinguish between physiologic jaundice and pathologic jaundice of the newborn. 3. Recognize the clinical manifestations of acute bilirubin encephalopathy and the permanent clinical sequelae of kernicterus.4. Describe the evaluation of hyperbilirubinemia from birth through 3 months of age. 5. Manage neonatal hyperbilirubinemia, including referral to the neonatal intensive care unit for exchange transfusion.

211 G to a variation of UDP-glucuronosyl transferase 1A1 gene and neonatal breastfeeding jaundice

Breastfeeding jaundice is a common problem in neonates who were exclusively breastfed, but its pathogenesis is still unclear. The uridine diphosphate glucuronosyl transferase 1A1 (UGT1A1) gene polymorphism was shown to contribute to the development of neonatal hyperbilirubinemia. We hypothesize that the variation of UGT1A1 gene may contribute to neonatal breastfeeding jaundice. We prospectively enrolled 688 near-term and term infants who were exclusively breastfed (BF group) or were supplemented by infant formula partially (SF group) before onset of hyperbilirubinemia. Genotyping of the promoter and exon1 of UGT1A1 was performed in all neonates. Neonates in BF group had a significantly higher maximal body weight loss ratio, peak bilirubin level, and a greater incidence of hyperbilirubinemia than those in SF group. Neonates with nucleotide 211 GA or AA variation in UGT1A1 genotypes had higher peak serum bilirubin levels and higher incidence of hyperbilirubinemia than WTs (GG). This phenomenon was only seen in BF group but not in SF group when subset analysis was performed. This suggests that neonates who carry the nucleotide 211 GA or AA variation within coding region in UGT1A1 gene are more susceptible to develop early-onset neonatal breastfeeding jaundice.

Transcutaneous bilirubin levels in late preterm neonates

OBJECTIVE

To examine transcutaneous bilirubin (TcB) levels in late preterm neonates.

STUDY DESIGN

Between July 2006 and December 2009, we performed 4387 TcB measurements with a BiliCheck bilirubinometer in 793 healthy late preterm neonates at designated times up to 120 postnatal hours. TcB percentiles are presented on an hour-specific nomogram. Mean increment TcB rates and the rates of increase for different percentiles are calculated as well.

RESULTS

We present a percentile-based nomogram that reflects the natural history of TcB in late preterm neonates up to the fifth day of life. TcB levels demonstrated a different pattern of increase in neonates who developed significant hyperbilirubinemia compared with those who did not. However, the rates of TcB increase were quite similar up to age 48 hours, with a substantial overlap of TcB values between the two groups.

CONCLUSIONS

We developed of a TcB nomogram designated for hour-specific evaluation of hyperbilirubinemia in neonates born between 35(0/7) and 37(6/7) weeks' gestation.

Heritability of apnea of prematurity: a retrospective twin study

BACKGROUND

Apnea of prematurity (AOP) is a disturbance in respiratory rhythm defined by idiopathic pauses in breathing that reduce blood oxygen levels and/or heart rate. It is a major clinical problem among preterm infants.

OBJECTIVES

The primary goal of this study was to estimate the genetic susceptibility to AOP in a cohort of preterm twins. A secondary aim was to identify risk factors associated with AOP in this cohort.

METHODS

A single-center, retrospective study (2000-2008) was performed by using data from 317 premature twin pairs (<36 weeks' gestational age). Heritability estimates were determined by comparing intrapair AOP concordance between 56 monozygotic and 161 dizygotic twin pairs by using structural equation modeling. Risk factors of AOP among a cohort of 543 premature twins were assessed by using mixed-effects logistic regression.

RESULTS

The heritability of AOP was 87% (95% confidence interval [CI]: 0.64-0.97) among same-gender twins. A gender-dependent model revealed that genetic factors accounted for 99% of the variance in male twins (95% CI: 0.89-1.00) and 78% of the variance in female twins (95% CI: 0.49-0.94). Significant risk factors for AOP were low gestational age (P<.001), cesarean delivery (P=.017), and conception through assisted reproductive technologies (P=.008).

CONCLUSIONS

These findings suggest that AOP has an important genetic basis underlying this developmental-related disorder of respiratory control. Future genomic studies may provide information on pathophysiological mechanisms that underlie AOP.

Glucose-6-phosphate dehydrogenase deficiency and severe neonatal hyperbilirubinemia: a complexity of interactions between genes and environment

Glucose-6-phosphate dehydrogenase deficiency is a commonly occurring genetic condition, likely to be encountered today in virtually any corner of the globe. Sudden episodes of hemolysis associated with the condition may result in exponential increases in serum total bilirubin concentrations to levels at which bilirubin-induced neurologic damage may occur. The hyperbilirubinemia is the result of complex interactions between genes and environment. Neonatal screening programs coupled with parental and medical caretaker education may be successful in limiting the severity of disease.

Hyperbilirubinemia in African American neonates: clinical issues and current challenges

African American neonates evidence a low incidence of hyperbilirubinemia yet account for more than 25% of the reported kernicterus cases in the USA. Glucose-6-phosphate dehydrogenase (G6PD) deficiency accounts for approximately 60%, and late preterm gestation and ABO hemolytic disease approximately 40% of these cases. Females heterozygous for G6PD A- harbor a population of G6PD-deficient red blood cells and are at risk for hyperbilirubinemia. Pre-discharge bilirubin measurement coupled with gestational age enhances the identification of neonates at hyperbilirubinemia risk. Parental education at the time of birth hospitalization discharge combined with timely follow-up may help to reduce the risk of developing hazardous hyperbilirubinemia.

Assessing jaundice in infants of 35-week gestation and greater

PURPOSE OF REVIEW

In 2004, the American Academy of Pediatrics officially recommended universal predischarge risk assessment for severe neonatal hyperbilirubinemia with the goal of minimizing subsequent risk of chronic bilirubin encephalopathy (formerly known as kernicterus). In this article, we review recent research regarding jaundice predischarge risk assessment, current expert recommendations for universal predischarge bilirubin screening, and concerns expressed in the literature regarding these recommendations.

RECENT FINDINGS

A group of experts have recently recommended universal predischarge bilirubin screening to identify newborns at risk for developing severe neonatal hyperbilirubinemia. In contrast, the United States Preventive Services Task Force states that there is insufficient evidence to make this recommendation. Transcutaneous bilirubinometry has emerged as a noninvasive, quick method to screen for neonatal hyperbilirubinemia, although refinement and validation of transcutaneous bilirubin nomograms are needed. Newer studies suggest that the combined use of a predischarge bilirubin and gestational age risk assessment offers a simple, objective, and accurate way to identify infants at risk for subsequent, severe hyperbilirubinemia.

SUMMARY

All newborns should be systematically assessed for risk of developing severe hyperbilirubinemia prior to hospital discharge. Although limited data exist to recommend its use universally, predischarge bilirubin screening should be considered given recent expert opinion. The role of transcutaneous bilirubinometry remains promising, although further research evaluating and validating its use in varied and diverse populations is imperative. Combined models of risk assessment may offer the best approach to identifying infants at risk for subsequent, severe hyperbilirubinemia.

Complex multifactorial nature of significant hyperbilirubinemia in neonates

OBJECTIVE

To determine whether glucose-6-phosphate dehydrogenase (G6PD), uridine-diphosphoglucuronosyltransferase 1A1 (UGT1A1), and hepatic solute carrier organic anion transporter 1B1 (SLCO1B1) gene variants occur at greater frequency in neonates with significant hyperbilirubinemia.

METHODS

Infants with gestational ages of >or=37 weeks and ages of <7 days were studied. Case subjects had >or=1 bilirubin level above the 95th percentile (high-risk zone), whereas control subjects had bilirubin levels of <40th percentile (low-risk zone) at study entry.

RESULTS

A total of 153 case subjects (median bilirubin level: 15.7 mg/dL) and 299 control subjects (median bilirubin level: 4.6 mg/dL) were evaluated. There were no statistical differences in the frequencies of G6PD, UGT1A1, and SCLO1B1 gene variants between case and control subjects (G6PD: 5.2% vs 3.3%; UGT1A1: 14.4% vs 9.4%; SLCO1B1: 73.2% vs 73.6%). However, coexpression of the G6PD African A- mutation with UGT1A1 and/or SLCO1B1 variants was seen more frequently for case subjects. Case subjects more often demonstrated >or=2 factors contributing to hyperbilirubinemia, including ABO blood group heterospecificity in which the mother had blood group O (47.7% vs 11.4%), positive direct Coombs test results (33.3% vs 4%), sibling treated with phototherapy (16.3% vs 5.4%), maternal circulating blood group antibodies (10.5 vs 0.7%), maternal diabetes mellitus (13.1% vs 6.4%), and maternal East Asian ethnicity (6.5% vs 1.3%).

CONCLUSIONS

Clinical contributors to hyperbilirubinemia were identified more frequently for case subjects but individually G6PD, UGT1A1, and SLCO1B1 variants were not. Coexpression of the G6PD African A- mutation with UGT1A1 and SLCO1B1 variants was seen more often for case subjects.