A practical gestational age-based algorithm for timely detection of hypothyroidism in premature infants.

OBJECTIVES: To assess utility and accuracy of a gestational age-based screening targeting premature infants to detect congenital hypothyroidism. STUDY DESIGN: A prospective cohort study was conducted in infants <35 weeks' gestational age with clinical outcomes at 2-3 years of age. Patients received newborn screenings at 24 hours and 10-14 days of life. Free T4 (FT4) and thyroid-stimulating hormone (TSH) levels were measured at one month of life and repeated based on algorithm by corrected gestational age. RESULTS: Among infants <35 weeks gestation (n = 938), the incidence of hypothyroidism requiring treatment was 1:58. TSH levels at one month of age was predictive of treatment (AUC 0.96, 95% CI 0.88-1). The optimal TSH threshold of 8 mIU/L (8 µU/ml) increased the specificity to 0.97 and sensitivity to 0.88. Following initiation of treatment for hypothyroidism during NICU hospitalization, 43.8% (n = 7) were diagnosed with permanent congenital hypothyroidism. CONCLUSIONS: Our study supports a gestational age-based screening algorithm for early detection of hypothyroidism in premature infants.

Secular Trends in Patent Ductus Arteriosus Management in Infants Born Preterm in the National Institute of Child Health and Human Development Neonatal Research Network.

We evaluated changes in patent ductus arteriosus (PDA) diagnosis and treatment from 2012 through 2021 in a network of US academic hospitals. PDA treatment decreased among infants born at 26-28 weeks but not among infants born at 22-25 weeks. Rates of indomethacin use and PDA ligation decreased while acetaminophen use and transcatheter PDA closure increased.

Respiratory Severity Score during the First 3 Hours of Life as a Predictor for Failure of Noninvasive Respiratory Support and Need for Late Rescue Surfactant Administration.

OBJECTIVE: Preterm infants often develop failure of noninvasive respiratory support. These infants miss the advantages of early rescue surfactant therapy. In this study, we evaluate the utility of respiratory severity score (RSS) during the first 3 hours of life (HOL) as a predictor for failure of noninvasive respiratory support. STUDY DESIGN: We conducted a post hoc analysis of infants between 23 and 40 weeks' gestational age who received usual care in the AERO-02 clinical trial. Univariate and multivariable logistic regression analysis were used to assess whether the RSS summary measures were associated with the odds of surfactant administration. RESULTS: Study involved 146 infants. Sixty-four infants (45%) received surfactant within the first 72 hours. Administration of surfactant was associated with the mean RSS (p < 0.01) and the linear trend (p < 0.01). CONCLUSION: We demonstrated that RSS during the first 3 HOL can predict failure of noninvasive respiratory support and need for late rescue surfactant administration. Optimal RSS cutoffs for early rescue surfactant therapy need to be determined in large cohort studies. KEY POINTS: · Early recognition of infants at risk of failure of noninvasive ventilation is important to prevent complications.. · It is desirable to identify patients who would benefit from early rescue surfactant treatment.. · RSS in first 3 hours can be used as a predictor of failure of noninvasive respiratory support..

Response to aerosolized calfactant in infants with respiratory distress syndrome; a post-hoc analysis of AERO-02 trial.

BACKGROUND: The aerosolized calfactant decreased the need for intubation in neonates with respiratory distress syndrome (AERO-02 trial). OBJECTIVE: To determine the oxygenation response to aerosolized calfactant among infants born 28 0/7-36 6/7 weeks with RDS in the AERO-02 trial. METHODS: Trends in hourly fraction of oxygen (FiO2), mean airway pressure (MAP) and respiratory severity score (RSS) were compared between the aerosolized calfactant (AC) and usual care (UC) groups from time of randomization for 72 h. RESULTS: A total of 353 subjects were included in the study. FiO2, MAP, and RSS were lower in the UC group. FiO2 decrease was seen after the first aerosolized calfactant dose. CONCLUSION: FiO2, MAP, and RSS were lower in the UC group. This is likely due to early and higher rate of liquid surfactant administration in the UC group. Decrease in FiO2 was noted in the AC group after the first aerosolization.

Predictors of successful treatment of respiratory distress with aerosolized calfactant.

INTRODUCTION: Predictors for successful aerosolized surfactant treatment are not well defined. OBJECTIVE: To identify predictors for successful treatment in the AERO-02 trial and the AERO-03 expanded access program. METHODS: Neonates receiving nasal continuous positive airway pressure (NCPAP) at the time of first aerosolized calfactant administration were included in this analysis. Associations between demographic and clinical predictors to need for intubation were examined using univariate testing and multivariate logistic regression analyses. RESULTS: Three hundred and eighty infants were included in the study. Overall, 24% required rescue by intubation. Multivariate modeling revealed that the predictors of successful treatment were a gestational age ≥31 weeks, a respiratory severity score (RSS) of <1.9, and <2 previous aerosol treatments. CONCLUSION: Gestational age, number of aerosols, and RSS are predictive of successful treatment. These criteria will help select patients most likely to benefit from aerosolized surfactant.

Oxygen Saturation Profiles in Healthy Term Infants in Early Postnatal Life.

OBJECTIVE: Oxygen saturation profiles generated by pulse oximetry are used as a clinical tool in the neonatal intensive care unit (NICU). There is limited evidence on normal oxygen saturation profile values in term infants. This study aimed to determine oxygen saturation profiles over an 8-hour monitoring period among healthy term neonates between 24 and 48 hours after birth. STUDY DESIGN: A prospective cohort study of healthy term neonates born at 37 to 41 weeks of gestation. Preductal oxygen saturations were continuously monitored for an 8-hour period between 24 and 48 hours of life using pulse oximetry. Oxygen profile histograms were recorded for analysis. The average percent oxygen saturation (SpO2) was measured over the entire study duration for each neonate and was characterized as the fraction of time of their SpO2 reading was in each of five intervals: ≤80, 81 to 84, 85 to 89, 90 to 94, and 95 to 100%. RESULTS: Seventy-five neonates were included in the study. Median SpO2 was 95.4%. Percentage time spent in each of the five SpO2 intervals was as follows: 0.07 (≤80), 0.15 (81-84), 0.88 (85-89), 26.9 (90-94), and 67.3% (95-100%). Eighteen infants (24%) spent the highest percentage of time in SpO2 of 90 to 94%. CONCLUSION: This study provides reference ranges for oxygen profiles in healthy term neonates during 24 to 48 hours of life. Nearly one-quarter of newborns spent the highest percentage of time in SpO2 of 90 to 94%. This data is important when interpreting oxygen saturation profiles of term neonates admitted to the NICU. KEY POINTS: · This study provide reference ranges for oxygen profiles in healthy term neonates during 24 to 48 hours.. · Median SpO2 was 95.4%.. · Nearly one quarter of newborns spent the highest percentage of time in SpO2 of 90 to 94%..

Surfactant Administration Through Laryngeal or Supraglottic Airways (SALSA): A Viable Method for Low-Income and Middle-Income Countries.

Administration of liquid surfactant through an endotracheal tube for the treatment of respiratory distress syndrome has been the standard of care for decades. A skilled health care provider is needed to perform this procedure. In lower-income and middle-income countries (LMICs), healthcare resources are often limited, leading to increased mortality of premature infants, many of whom would benefit from surfactant administration. Therefore, having a simplified procedure for delivery of surfactant without the need for advanced skills could be life-saving, potentially diminish gaps in care, and help ensure more equitable global neonatal survival rates. Modifications to the standard approach of surfactant administration have been put into practice and these include: INtubation-SURfactant-Extubation (INSURE), thin catheter surfactant administration (TCA), aerosolized surfactant, and surfactant administration through laryngeal or supraglottic airways (SALSA). Although there is a need for larger studies to evaluate the comparative effectiveness of these newer methods, these methods are being embraced by the global community and being implemented in various settings throughout the world. Because the SALSA technique does not require laryngoscopy, a provider skilled in laryngoscopy is not required for the procedure. Therefore, because of the ease of use and safety profile, the SALSA technique should be strongly considered as a viable method of delivering surfactant in LMICs.

Thyroid Hormone Function in Small for Gestational Age Term Newborns.

OBJECTIVE: To test the hypothesis that term-born small for gestational age (SGA) neonates have elevated thyroid-stimulating hormone (TSH) concentrations and an increased incidence of congenital hypothyroidism compared with non-SGA term neonates. STUDY DESIGN: This retrospective cohort study included all term neonates screened in Wisconsin in 2015 and 2016. The cohort was divided based on SGA status, defined as birth weight <10th percentile as calculated from the World Health Organization's sex-specific growth charts for age 0-2 years. TSH concentration on first newborn screening performed between birth and 96 hours of life and incidence of congenital hypothyroidism were compared between the SGA and non-SGA groups. RESULTS: A total of 115 466 term neonates, including 11 498 (9.96%) SGA neonates, were included in the study. TSH concentration and incidence of congenital hypothyroidism was significantly higher in the SGA group, but only TSH concentration remained significant when adjusted for potential confounding variables. CONCLUSIONS: Our data do not support a higher incidence of congenital hypothyroidism in term SGA neonates after adjusting for potential confounders. However, TSH concentrations were higher in term SGA neonates compared with term non-SGA neonates. The effects of mild thyroid hormone dysfunction on neurodevelopmental outcomes and development of chronic medical conditions merit long-term study.

Hypothyroxinemia Detected at 4 Weeks of Life in Preterm Infants Born at Less than 30 Weeks of Gestation.

OBJECTIVE: Data on free thyroxine (FT4) concentrations beyond first 2 weeks of preterm infants are limited. This study was aimed to describe the association between perinatal characteristics and FT4 concentrations and the incidence of hypothyroxinemia at 4 weeks. STUDY DESIGN: Retrospective analysis of serum thyroid function tests at 4 weeks in preterm infants <30 weeks of gestation. Association between FT4 at 4 weeks of life and perinatal characteristics were determined by bivariate analysis and multivariable regression. Incidence of hypothyroxinemia was determined using a gestational age adjusted definition based on in utero levels at the equivalent postmenstrual age. RESULTS: The study cohort consisted of 280 infants. FT4 concentrations at 4 weeks of life were significantly associated with gestational age, birth weight, gender, and maternal history of thyroid disease. Hypothyroxinemia was found in 32.8% of the study cohort. CONCLUSION: Perinatal characteristics are associated with FT4 concentrations at 4 weeks of life. Nearly one-third of infants born <30 weeks had hypothyroxinemia at 4 weeks of life when compared with in utero levels at the equivalent postmenstrual age.

High Black infant mortality in Wisconsin: factors associated with the ongoing racial inequity.

BACKGROUND: Wisconsin has the highest Black infant mortality rate (IMR) in the nation. OBJECTIVE: Evaluate factors associated with racial inequity in IMR in Wisconsin. STUDY DESIGN: Births/deaths/IMR for Black and White infants from 2011 to 2016 were obtained from the Wisconsin Interactive Statistics on Health system, stratified by gestational age (GA), and compared using direct adjustment method. IMR were compared based on cause of death, maternal age, and education. RESULTS: Crude and adjusted IMR was 13.7 and 9.1 for black infants. Respective IMR for white infants was 4.8 and 5.3. Crude IMR was 180% higher in Black infants. After controlling for GA, IMR among Black infants was 70% higher. In term Black infants, deaths due to sudden infant death syndrome (SIDS), accidents, and assaults were markedly high. CONCLUSIONS: Higher IMR in Black infants was due to increased premature births and increased mortality among term infants. Potentially modifiable causes of death were SIDS, accidents, and assaults.

Thyroid-stimulating hormone reference ranges for moderate-to-late preterm infants.

BACKGROUND: Identifying congenital hypothyroidism through newborn screening (NBS) is higher among moderate-to-late preterm (MLPT) infants. Currently, the same thyroid-stimulating hormone (TSH) cutoffs are used for term and preterm infants. TSH reference ranges for MLPT infants are not currently available. OBJECTIVE: To determine TSH reference ranges for MLPT infants. METHODS: We analyzed 10,987 TSH levels on NBS samples performed on 8499 MLPT infants born between 32 and 36 weeks gestation. RESULTS: TSH median, 5th, 25th, 75th, 95th, and 99th percentiles were defined from day 1 until day 14 of life. TSH levels gradually decreased after birth and reached a plateau around day 6. CONCLUSION: Using a state-wide cohort, we constructed TSH reference charts from day 1 until day 14 for MLPT infants. Relationship between age-adjusted TSH percentiles and long-term neurodevelopmental outcomes should be determined in future studies to define optimal TSH cutoffs for MLPT infants.

Thyroid-Stimulating Hormone Reference Ranges for Preterm Infants.

BACKGROUND AND OBJECTIVES: Many newborn screening (NBS) programs now perform repeat or serial NBS to detect congenital hypothyroidism. There is wide variation in thyroid-stimulating hormone (TSH) cutoffs used by NBS programs. Data on TSH reference ranges in preterm infants at increasing postnatal age are limited. Our study objective was to determine TSH reference ranges for preterm infants born at <32 weeks' gestation. METHODS: We analyzed serial TSH levels on NBS performed on infants born between 22 and 31 weeks' gestation from 2012 to 2016 in Wisconsin. The study cohort was divided into 2 groups (22-27 and 28-31 weeks), and TSH percentiles were defined from birth to the term equivalent gestational age. RESULTS: The study cohort consisted of 1022 and 2115 infants born at 22 to 27 and 28 to 31 weeks' gestation, respectively. The 95th percentile TSH level for the group born at 22 to 27 weeks' gestation gradually decreased and reached a nadir at ∼10 to 11 weeks. In contrast, for the group born at 28 to 31 weeks' gestation, the 95th percentile TSH level reached a nadir at ∼5 to 6 weeks. At 3 to 4 weeks after birth, the 95th percentile TSH level ranged from 11 to 11.8 µIU/mL for the group born at 22 to 27 weeks' gestation and ranged from 8.2 to 9 µIU/mL for the group born at 28 to 31 weeks' gestation. CONCLUSIONS: Using a statewide cohort of preterm infants, we constructed TSH reference charts from birth to the term equivalent gestation for preterm infants born at <32 weeks' gestation. Use of a single cutoff for all preterm infants might lead to misdiagnosis. The differences in TSH levels according to gestational-age categories might explain the increased frequency in congenital hypothyroidism diagnoses among preterm infants. These data are useful for defining age-adjusted NBS TSH cutoffs for preterm infants.

Increased Congenital Hypothyroidism Detection in Preterm Infants with Serial Newborn Screening.

OBJECTIVES: To determine the incidence of congenital hypothyroidism in preterm infants and to identify associated risk factors. STUDY DESIGN: A population-based cohort study was performed in preterm infants born at <32 weeks of gestational age between 2012 and 2016 in Wisconsin. Newborn screening (NBS) results and demographic data were obtained from the Wisconsin State Laboratory of Hygiene. Congenital hypothyroidism was subdivided to early TSH elevation (eTSH) and delayed TSH elevation (dTSH). Multivariate logistic regression analyses were performed to identify demographic factors associated with dTSH. RESULTS: A total of 3137 preterm infants born at 22-31 weeks of gestational age were included in the study. Mean gestational age was 28.4 ± 2.4 weeks and mean birth weight was 1191 ± 399 g. Forty-nine infants were diagnosed with congenital hypothyroidism. The overall incidence of congenital hypothyroidism was 1.56%, including a 0.13% incidence of eTSH and a 1.43% incidence of dTSH. Birth weight <1000 g, multiple gestation, and initial TSH level were identified as independent predictors for dTSH. CONCLUSION: Targeted serial NBS in Wisconsin led to a higher rate of diagnosis of congenital hypothyroidism in preterm infants than has been reported previously. The majority (92%) of congenital hypothyroidism cases were diagnosed with dTSH. Birth weight <1000 g, multiple gestation, and elevated initial TSH level were associated with increased risk for development of dTSH. We recommend obtaining targeted serial NBS in preterm infants (<32 weeks of gestational age) to improve the detection of congenital hypothyroidism.

Antenatal steroids and thyroid hormone function in preterm infants.

BACKGROUND: Antenatal steroids (ANS) are used widely for women at risk of preterm delivery. Evidence on the effects of ANS on thyroid hormone function in preterm infants is limited. OBJECTIVES: To determine effects of ANS on thyroid hormone function in preterm infants. METHODS: A retrospective cohort study of preterm infants born before 30 weeks of gestation. Infants were divided into no ANS, partial ANS, and complete ANS groups. Thyroid function tests at day of life 30 were compared. RESULTS: 260 Infants were included. A significantly higher proportion of patients were started on levothyroxine (LT4) in no ANS group and partial ANS group compared to complete ANS group. Logistic regression analysis revealed that infants in no ANS group are more likely to have TSH > 6 µIU ml-1 and started on LT4 compared to complete ANS group. CONCLUSION: Infants in no ANS group are more likely to have thyroid dysfunction compared to complete ANS group.

Role of Early Pulmonary Hypertension as a Risk Factor for Late Pulmonary Hypertension in Extremely Preterm Infants.

OBJECTIVE: The evidence on the role of early pulmonary vascular disease (PVD) in the development of late pulmonary hypertension (PH) in the extremely preterm infants is limited. Objectives were to determine the incidence of early and late PH in extreme preterm infants and to evaluate the role of early PH as a risk factor for development of clinically detected late PH. METHODS: It was a retrospective analysis of early echocardiograms (day of life 5-14) in preterm infants, 22 to 27 weeks' gestation, admitted to the University of Iowa NICU between July 01, 2012 to June 30, 2015. Late echocardiograms performed for clinical suspicion of PH were also analyzed. RESULTS: A total of 154 infants were included in the study. Early PH was diagnosed in 31 (20%) infants. Twenty-four (16%) infants were evaluated for clinically suspected PH. Eight (5%) infants were diagnosed with late PH. Infants with early PH had echocardiograms performed earlier than infants without the evidence of early PH. Early PH was not associated with the development of late PH (p = 0.99). CONCLUSION: Early PH is common among extremely preterm infants (20%). Five percent of infants had clinically detected late PH. Infants with early PH had echocardiograms performed earlier than infants without the evidence of early PH. Early PH was not associated with the development of clinically detected late PH.

Polymorphisms in urea cycle enzyme genes are associated with persistent pulmonary hypertension of the newborn.

BackgroundPersistent pulmonary hypertension of the newborn (PPHN) is characterized by elevated pulmonary vascular resistance. Endogenous nitric oxide is critical for regulation of pulmonary vascular resistance. Nitric oxide is generated from L-arginine, supplied by the urea cycle (UC). We hypothesized that polymorphisms in UC enzyme genes and low concentrations of UC intermediates are associated with PPHN.MethodsWe performed a family-based candidate gene analysis to study 48 single-nucleotide polymorphisms (SNPs) in six UC enzyme genes. Genotyping was carried out in 94 infants with PPHN and their parents. We also performed a case-control analysis of 32 cases with PPHN and 64 controls to identify an association between amino-acid levels on initial newborn screening and PPHN.ResultsThree SNPs (rs41272673, rs4399666, and rs2287599) in carbamoyl phosphate synthase 1 gene (CPS1) showed a significant association with PPHN (P=0.02). Tyrosine levels were significantly lower (P=0.003) and phenylalanine levels were significantly higher (P=0.01) in cases with PPHN. There was no difference in the arginine or citrulline levels between the two groups.ConclusionsThis study suggests an association (P<0.05) between SNPs in CPS1 and PPHN. These findings warrant further replication in larger cohorts of patients.

Polymorphisms in NR5A2, gene encoding liver receptor homolog-1 are associated with preterm birth.

BACKGROUND: Preterm birth (PTB) is a major cause of neonatal mortality and morbidity. There is strong evidence of genetic susceptibility. Objective of this study was to identify genetic variants contributing to PTB. METHODS: Genotyping was performed for 24 single nucleotide polymorphisms (SNPs) in 4 candidate genes (NR5A2, FSHR, FOXP3, and SERPINH1). Genotyping was completed on 728 maternal triads (mother and maternal grandparents of a preterm infant). Data were analyzed with Family Based Association Test. RESULTS: For all maternal triads rs2737667 of NR5A2 showed significant association at P = 0.02. When stratifying by gestational age three SNPs in NR5A2 had P values <0.05 in the <32-wk gestational age group (rs12131233, P = 0.007; rs2737667, P = 0.04; rs2816949, P = 0.02). When preterm premature rupture of membranes cases were excluded rs2737667 of NR5A2 showed the strongest association with a P value <0.0002. This association remained significant after correction for multiple testing. CONCLUSION: This study suggests a potential association between intronic SNPs in the NR5A2 gene and PTB. NR5A2 gene encodes for the liver receptor homolog-1 protein, which plays a critical role in regulation of cholesterol metabolism, steroidogenesis, and progesterone synthesis. These findings suggest that NR5A2 may be important in the pathophysiology of PTB and exploring noncoding regulators of NR5A2 is warranted.