Do cortisol concentrations predict short-term outcomes in extremely low birth weight infants?

Association between ambient air pollution a week prior to delivery and preterm birth using a nationwide study in Sweden

BACKGROUND

Air pollution exposure has been linked with increased risk of preterm birth, which is one of the leading causes of infant mortality. Limited studies have attempted to explore these associations in low-polluted areas. In this study, we aimed to assess the association between short-term exposure to ambient air pollution and preterm birth in Sweden.

METHOD

In this population-based study we included preterm births between 2014 and 2019 from the Swedish Pregnancy Register. We applied a spatiotemporal model to estimate daily levels of particulate matter <2.5 μm (PM2.5), PM < 10 μm (PM10), nitrogen dioxide (NO2), and ozone (O3) at the residential address of each participant. We applied a time-stratified case-crossover design with conditional logistic regression analysis to estimate odds ratios (OR) of preterm birth per 10 μg/m3 (PM10, NO2, O3) and 5 μg/m3 (PM2.5) increase in air pollution exposure at 0-6-day lag. Two-pollutant models were applied to evaluate the independent association of each exposure on preterm birth. We also stratified by maternal characteristics to identify potential effect modifiers.

RESULTS

28,216 (4.5%) preterm births were included. An increase in O3 exposure was associated with increased odds of preterm birth [OR = 1.06 per 10 μg/m3 (95% CI, 1.02; 1.10]. PM2.5 and PM10 were not significantly associated with preterm birth, and NO2 displayed a negative nonlinear association with preterm birth. We did not observe any notable effect modification, but we found suggestive larger associations between O3 and preterm birth when stratifying by male sex, spontaneous delivery, and spring season.

CONCLUSIONS

Increased O3 exposure one week before delivery was associated with an increased risk of preterm birth in Sweden, a country with levels of air pollution below the current World Health Organization air quality guidelines. Increases in O3 levels with climate change make these findings especially concerning.

Steroid Metabolomic Signature in Term and Preterm Infants

Adrenal function is essential for survival and well-being of preterm babies. In addition to glucocorticoids, it has been hypothesized that C19-steroids (DHEA-metabolites) from the fetal zone of the adrenal gland may play a role as endogenous neuroprotective steroids. In 39 term-born (≥37 weeks gestational age), 42 preterm (30-36 weeks) and 51 early preterm (<30 weeks) infants 38 steroid metabolites were quantified by GC-MS in 24-h urinary samples. In each gestational age group, three distinctive cluster were identified by pattern analysis (k-means clustering). Individual steroidal fingerprints and clinical phenotype were analyzed at the 3rd day of life. Overall, the excretion rates of C21-steroids (glucocorticoid precursors, cortisol, and cortisone metabolites) were low (<99 μg/kg body weight/d) whereas the excretion rates of C19-steroids were up to 10 times higher. There was a shift to higher excretion rates of C19-steroids in both preterm groups compared to term infants but only minor differences in the distribution of C21-steroids. Comparable metabolic patterns were found between gestational age groups: Cluster 1 showed mild elevation of C21- and C19-steroids with the highest incidence of neonatal morbidities in term and severe intraventricular hemorrhage in early preterm infants. In cluster 2 lowest excretion in general was noted but no clinically unique phenotype. Cluster 3 showed highest elevation of C21-steroids and C19-steroids but no clinically unique phenotype. Significant differences in steroid metabolism between clusters are only partly reflected by gestational age and disease severity. In early preterm infants, higher excretion rates of glucocorticoids and their precursors were associated with severe cerebral hemorrhage. High excretion rates of C19-steroids in preterm infants may indicate a biological significance.

Cortisol in deciduous tooth tissues: A potential metric for assessing stress exposure in archaeological and living populations

OBJECTIVE

Cortisol is a glucocorticoid hormone produced by the hypothalamic-pituitary-adrenal axis that is regularly assessed in modern human and non-human populations in saliva, blood, and hair as a measure of stress exposure and stress reactivity. While recent research has detected cortisol concentrations in modern and archaeological permanent dental tissues, the present study assessed human primary (deciduous) teeth for cortisol concentrations.

MATERIALS AND METHODS

Fifty-one dentine and enamel samples from nine modern and 10 archaeological deciduous teeth were analyzed for cortisol concentrations via enzyme-linked immunosorbent assay (ELISA).

RESULTS

Detectable concentrations of cortisol were identified in 15 (of 32) dentine and 8 (of 19) enamel samples coming from modern and archaeological deciduous teeth.

CONCLUSIONS

This study is the first known analysis of cortisol from deciduous dental tissues, demonstrating the potential to identify measurable concentrations.

SIGNIFICANCE

The ability to analyze deciduous teeth is integral to developing dental cortisol methods with multiple potential future applications, including research on the biological embedding of stress in the skeleton. This study marks a key step in a larger research program to study stress in primary dentition from living and archaeological populations.

LIMITATIONS

Multiple samples generated cortisol values that were not detectable with ELISA. Minimum quantities of tissue may be required to generate detectable levels of cortisol.

SUGGESTIONS FOR FURTHER RESEARCH

Future research should include larger sample sizes and consideration of intrinsic biological and extrinsic preservation factors on dental cortisol. Further method validation and alternative methods for assessing dental cortisol are needed.

Discharge Practices for Infants with Bronchopulmonary Dysplasia: A Survey of National Experts

OBJECTIVE

To establish consensus practices among a panel of national experts for the discharge of premature infants with bronchopulmonary dysplasia (BPD) from the hospital to home.

STUDY DESIGN

We conducted a Delphi study that included US neonatologists and pediatric pulmonologists from the Bronchopulmonary Dysplasia Collaborative to establish consensus practices-defined as recommendations with at least 80% agreement-for infants with BPD being discharged from the hospital. Specifically, we evaluated recommendations for diagnostic tests to be completed around discharge, follow-up respiratory care, and family education.

RESULTS

Thirty-one expert participants completed 3 rounds of surveys, with a 99% response rate (92 of 93). Consensus was established that infants with moderate-severe BPD (ie, those who remain on respiratory support at 36 weeks) and those discharged on oxygen should be targeted for in-person pulmonary follow-up within 1 month of hospital discharge. Specialized neonatal follow-up is an alternative for infants with mild BPD. Infants with moderate or severe BPD should have an echocardiogram performed after 36 weeks to screen for pulmonary hypertension. Infants with BPD warrant additional evaluations if they have growth restriction or poor growth, pulmonary hypertension, or tachypnea and if they are discharged to home on oxygen, diuretics, or nonoral feeds.

CONCLUSIONS

This Delphi survey establishes expert consensus around best practices for follow-up respiratory management and routine evaluation for infants with BPD surrounding neonatal discharge. Areas of disagreement for which consensus was not established are discussed.

Early Physiological and Adrenal Effects of Budesonide Mixed with Surfactant in Large Observational Preterm Cohort Study

BACKGROUND

The combination of surfactant and budesonide has been shown to decrease BPD rates and severity. Budesonide may be released systemically from lungs, and the effects on the immature adrenal glands are not known.

OBJECTIVE

The aim of this study was to determine if adrenal suppression rates are higher in preterm infants receiving budesonide with surfactant compared to surfactant alone.

METHODS

A retrospective chart review of 608 infants ≤1,250 g received intubation for surfactant therapy from 2013 through 2020. In August 2016, budesonide was added to surfactant for these infants. Indicators of adrenal suppression, including mean blood pressures, plasma electrolyte levels, hydrocortisone use, and the use of vasoactive medications, were analyzed for the first 14 days after birth. Respiratory variables, biochemical signs of adrenal insufficiency, and neonatal morbidities were analyzed.

RESULTS

There was no difference in hydrocortisone administration in the first 14 days between infants receiving budesonide with surfactant (n = 314) or surfactant alone (n = 294) (23% vs. 19%, p = 0.38). Budesonide exposed infants received hydrocortisone 3 days later than surfactant only infants (median DOL 5 vs. 2, p < 0.001). Infants receiving budesonide had higher blood pressures, required less dopamine (19% vs. 39%, p < 0.001) and dobutamine (2% vs. 6%, p = 0.02). Budesonide exposed infants were discharged home after a shorter NICU stay (85 days vs. 94 days, p = 0.02) and at a younger gestational age (39 vs. 40 weeks, p = 0.001).

CONCLUSIONS

The use of surfactant and budesonide does not alter the rate of hydrocortisone use, but does delay the timing of treatment initiation and decreases the use of vasoactive medications.

Risk Factors for Periventricular Leukomalacia in Preterm Infants: A Systematic Review, Meta-analysis, and GRADE-Based Assessment of Certainty of Evidence

BACKGROUND

We analyzed the certainty of evidence (CoE) for risk factors of periventricular leukomalacia (PVL) in preterm neonates, a common morbidity of prematurity.

METHODS

Medline, CENTRAL, Embase, and CINAHL were searched. Cohort and case-control studies and randomised randomized controlled trials were included. Data extraction was performed in duplicate. A random random-effects meta-analysis was utilizedused. CoE was evaluated as per Grading of Recommendations Assessment, Development and Evaluation (GRADE) guidelines.

RESULTS

One hundred eighty-six studies evaluating 95 risk factors for PVL were included. Of the 2,509,507 neonates assessed, 16,569 were diagnosed with PVL. Intraventricular hemorrhage [adjusted odds ratio: 3.22 (2.52-4.12)] had moderate CoE for its association with PVL. Other factors such as hypocarbia, chorioamnionitis, PPROM >48 hour, multifetal pregnancy reduction, antenatal indomethacin, lack of antenatal steroids, perinatal asphyxia, ventilation, shock/hypotension, patent ductus arteriosus requiring surgical ligation, late-onset circulatory collapse, sepsis, necrotizing enterocolitis, and neonatal surgery showed significant association with PVL after adjustment for confounders (CoE: very low to low). Amongst the risk factors associated with mother placental fetal (MPF) triad, there was paucity of literature related to genetic predisposition and defective placentation. Sensitivity analysis revealed that the strength of association between invasive ventilation and PVL decreased over time (P < 0.01), suggesting progress in ventilation strategies. Limited studies had evaluated diffuse PVL.

CONCLUSION

Despite decades of research, our findings indicate that the CoE is low to very low for most of the commonly attributed risk factors of PVL. Future studies should evaluate genetic predisposition and defective placentation in the MPF triad contributing to PVL. Studies evaluating exclusively diffuse PVL are warranted.

Absence of relationship between serum cortisol and critical illness in premature infants

BACKGROUND

Inadequate cortisol production in response to critical illness in extremely preterm infants may exacerbate poor outcomes. Despite commonly measuring cortisol concentration and administering hydrocortisone for presumed adrenal insufficiency, the relationship between serum cortisol concentration and illness severity remains unclear in this unique population.

OBJECTIVE

To determine the relationship between cortisol concentrations and illness severity as measured by the Score for Neonatal Acute Physiology II, neonatal Sequential Organ Failure Assessment and Vasoactive-Inotropic Score in premature infants.

DESIGN/METHODS

This retrospective, single-center cohort study included preterm infants born <30 weeks gestational age admitted to a level IV neonatal intensive care unit (NICU) between June 2011 and July 2018, who had a serum cortisol obtained for clinical indications before 36 weeks PMA. Demographic data were collected on infants and mothers. Nine clinical variables were identified a priori that could potentially modify cortisol concentration including critical illness. Univariate and multivariable analyses determined the relationship between cortisol concentration and each of these variables.

RESULTS

A total of 224 preterm infants with pretreatment serum cortisol concentration met criteria for inclusion. The median (IQR) gestational age at birth was 25 weeks (24, 26) and at cortisol measurement was 26 weeks (25, 28). The median cortisol was 13.3 ug/dL. Non-survivors had the highest values. Cortisol concentration did not correlate with any of the selected illness severity scores.

CONCLUSIONS

Cortisol concentrations in extremely preterm infants did not correlate with illness severity regardless of gestational age. Further studies are needed to identify clinically useful mediators of adrenal dysfunction and to guide clinical management.

Corticosteroids for Neonatal Hypotension

Several limitations and controversies surround the definition of hypotension; however, it remains one of the most common problems faced by neonates. Approximately 15% to 30% of neonates with hypotension fail to respond to volume and/or vasopressor or inotropes. They are considered to have refractory hypotension. Although it is thought to have multiple causes, absolute and relative adrenal insufficiency is considered as the main reason for refractory hypotension. This article focuses on the role of adrenal insufficiency in causing refractory hypotension in preterm and term infants, the different options of corticosteroids available, and their risk/benefit profiles.

Assessment of adrenal function at birth using adrenal glucocorticoid precursor to product ratios to predict short-term neonatal outcomes

BACKGROUND

Most neonatal outcomes in neonates are related to normal adrenal gland function. Assessment of adrenal function in a sick preterm neonate remains a challenge, thus we hypothesized that adrenal steroid precursors to their product ratios have a direct relationship with neonatal outcomes.

METHODS

We studied demographics of pregnancy and neonatal outcomes in 99 mother-infant pairs (24-41 weeks) and assayed 7 glucocorticoid precursors in the cortisol biosynthesis/degradation pathway. We correlated antenatal factors and short-term neonatal outcomes with these precursors and their ratios to assess maturity of individual enzymes.

RESULTS

We found no correlation between cortisol levels with antenatal factors and outcomes. Antenatal steroid use impacted several cortisol precursors. 17-OH pregnenolone-to-cortisol ratio at birth was the best predictor of short-term neonatal outcomes, such as hypotension, RDS, IVH and PDA. A cord blood 17-OH pregnenolone:cortisol ratio of <0.21 predicts which neonate will have a normal outcome with a high sensitivity and specificity.

CONCLUSIONS

Maternal factors and antenatal steroids impact neonatal adrenal function and leads to maturation of adrenal function. 17-OH pregnenolone:cortisol ratio and not cortisol is the best predictor of adrenal function. Adrenal function can be assessed by evaluating the profile of adrenal steroids.

Basal serum cortisol concentration in very low birth weight infants

BACKGROUND

The aim of our study was to measure the basal serum cortisol concentration immediately after birth and to determine its association with perinatal factors and clinical outcomes in very low birth weight (VLBW) infants.

METHODS

Basal serum cortisol level was obtained within one hour after birth in inborn VLBW infants. The association between the basal serum cortisol level and perinatal and clinical outcomes was analyzed by comparing the groups with high versus low cortisol levels.

RESULTS

In total, 80 infants were included. The median concentration of basal serum cortisol was 167 nmol/L with an interquartile range of 98-298 nmol/L. The basal serum cortisol concentration positively correlated with elapsed time from the last betamethasone dose. Low serum cortisol concentration was associated with antenatal corticosteroid therapy, low lactic acid level, and low leukocyte count at birth. Basal serum cortisol level was not associated with mortality and neonatal morbidities including hypotension and severe grade intraventricular hemorrhage.

CONCLUSION

Both maternal corticosteroid therapy and perinatal distress may affect the basal serum cortisol concentration in VLBW infants early after birth.

Establishing a conceptual framework of the impact of placental malaria on infant neurodevelopment

A novel conceptual framework to describe the relationship between placental malaria and adverse infant neurodevelopmental outcomes is proposed. This conceptual framework includes three distinct stages: (1) maternal and environmental risk factors for the development of placental malaria; (2) placental pathology and inflammation associated with placental malaria infection; and (3) postnatal impacts of placental malaria. The direct, indirect, and bidirectional effects of these risk factors on infant neurodevelopment across the three stages were critically examined. These factors ultimately culminate in an infant phenotype that not only leads to adverse birth outcomes, but also to increased risks of neurological, cognitive, and behavioural deficits that may impact the quality of life in this high-risk population. Multiple risk factors were identified in this conceptual framework; nonetheless, based on current evidence, a key knowledge gap is the uncertainty regarding which are the most important and how exactly they interact.

Novel method of measuring chronic stress for preterm infants: Skin cortisol

BACKGROUND AND OBJECTIVES

Infants who begin life in the medicalized environment of the neonatal intensive care unit (NICU) do so under stressful conditions. Environmental exposures are often abrasive to vulnerable infants, while invasive and noninvasive lifesaving interventions provide additional pain and/or stress. The most commonly selected biomarker to measure stress is cortisol. The skin is the barrier between the external environment and communicates with our neurological, endocrine and immune regulatory networks. To examine if skin cortisol may be a reliable biomarker of stress, NICU stress exposure and repeated measurements of skin cortisol in very preterm infants were examined retrospectively during the first 6 weeks of life. The temporal relationship between skin cortisol and NICU stress exposure was also analyzed.

MATERIALS AND METHODS

Participants included 82 preterm infants born weighing less than 1500 g, admitted to a level III NICU, with a mean gestational age of 28.5 weeks. Infants were studied from birth through 6 weeks of life. NICU stress data was collected using the Neonatal Infant Stressor Scale. Skin samples were collected using d-squame tape as soon after birth as possible and every two weeks thereafter.

RESULTS

On average, infants experienced approximately 43 stressful events per day during the first 6 weeks of life in the NICU. Stress level and cortisol reactivity varied by gestation age. Higher stress resulted in higher cortisol for infant >28 weeks; lower stress scores were associated with higher stress for infants <28 weeks. Stress exposure during 7 days prior to cortisol sampling yielded the highest AUC for the 2 groups. A statistically significant interaction was identified between gestational age and stress exposure during the previous 7 days (p < 0.01).

CONCLUSION

This is the first study to demonstrate skin cortisol as a preterm infant biomarker of chronic stress exposure. For infants with appropriate skin maturation, this non-invasive sampling method provides several benefits. Importantly, this method may be less intrusive and disruptive for preterm infants.

Prematurity and perinatal adversity effects hypothalamic-pituitary-adrenal axis reactivity to social evaluative threat in adulthood

This study examined the long-term effects of prematurity and perinatal adversity on individual differences in stress-related reactivity and regulation of the HPA axis. A prospective sample of 155 infants born preterm and healthy (n = 20), medical illness (n = 48), neurological illness (n = 26), and small for gestational age (n = 24) and full-term (n = 37) were recruited between 1985 and 1989. At age 23 years, multiple saliva samples were collected before and after participation in the Trier Social Stress Test and later assayed for cortisol. Results reveal that at age 23 years, infants born premature with neurological complications showed higher cortisol reactivity to social evaluative threat compared to either their full-term, small for gestation age, medically ill, or healthy preterm peers. Findings are discussed in terms of implications for contemporary theories that propose effects of early adversity on biological sensitivities and susceptibilities, which translate experience into developmental outcomes related to poor health and risk for disease.

An evaluation of hydrocortisone dosing for neonatal refractory hypotension

OBJECTIVE

The objective of the study was to compare blood pressure, vasoactive medication requirements and adverse outcomes after administration of high- versus low-dose hydrocortisone (HC) in preterm infants.

STUDY DESIGN

This is a retrospective analysis of 106 infants ⩽28 weeks gestational age with hypotension requiring vasoactive infusions and high-dose (4 mg kg^-1 per day, n=50), low-dose (1 to 3 mg kg^-1 per day, n=20) or no HC (n=36) from 2011 to 2015. Groups were compared by two-tailed t-test or χ², and correlation estimated by multivariable logistic regression.

RESULTS

There were no differences in measured efficacy between the low- and high-dose groups. Infants with pre-treatment cortisol >15 mcg dl^-1 who received HC therapy showed less improvement in vasoactive burden, increased hyperglycemia (P=0.015) and increased death independent of HC dose (odds ratio 26.3, 3.5 to 198.3, P=0.002).

CONCLUSION

These results support using the lowest effective HC dose in preterm infants. In addition, HC therapy should likely be avoided in infants who are not cortisol deficient.

Long-Term Effects of Prematurity, Cumulative Medical Risk, and Proximal and Distal Social Forces on Individual Differences in Diurnal Cortisol at Young Adulthood

This study examined the effects of prematurity, cumulative medical risk, and proximal and distal social forces on individual differences in the activity of the hypothalamic-pituitary-adrenal (HPA) axis in young adulthood. A prospective sample of 149 infants born healthy preterm (PT; n = 22), sick PT ( n = 93, medical illness, neurological illness, small for gestational age), and full term ( n = 34) was recruited from a Level III neonatal intensive care unit in southern New England between 1985 and 1989 and followed to age 23 years. Cumulative medical risk was indexed across seven assessment waves (spanning 17 years) using medical and neurological health status at birth, toddlerhood (ages 18 and 30 months), childhood (ages 4 and 8 years), and adolescence (ages 12 and 17 years). Distal risk included socioeconomic status (SES) at birth. Proximal social factors were indexed from assessments of the home environment and measures of child vulnerability and maternal self-esteem, involvement, and control style from birth, 4 years, 8 years, and 12 years. At age 23 years, five saliva samples were collected upon awakening, 45 min after waking, 4 hr after waking, 8 hr after waking, and bedtime (later assayed for cortisol). Results reveal effects of cumulative medical risk on the diurnal pattern of HPA axis activity, with moderating effects of SES and proximal social factors. Findings are discussed in terms of implications for contemporary theories related to developmental sensitivity and susceptibility to context and the developmental origins of health and disease theory.

Cortisol precursors in neonates with vasopressor-resistant hypotension in relationship to demographic characteristics

OBJECTIVE

To correlate between cortisol precursors in neonates with vasopressor resistant hypotension and demographic characteristics.

METHODS

We investigated 48 neonates with vasopressor-resistant hypotension. Gestation at birth ranged from 34 to 42 weeks and postnatal age from 4 to 14 days. Cortisol and precursor steroids were measured soon after the onset of volume expansion and inotropes for treatment of shock. Their concentrations were determined using liquid chromatography/mass spectrometry.

RESULTS

In neonates with vasopressor-resistant hypotension, the serum levels of cortisol were within normal nonstress range. There was a strong negative linear association between postnatal age and dehydroepiandrosterone level (r = -0.50, p < .01), which decreased with neonatal age. In addition, there was a significant positive association between gestational age at birth and 17-hydroxy-pregnenolone (r = 0.33, p = .02). No further significant associations were evident between the neonatal weight, duration of gestation or gender and of the levels of cortisol or the other steroids (p > .05). The cause of therapy-resistant hypotension did not appear to influence the steroid levels.

CONCLUSIONS

Cortisol stress response is absent in these severely ill late preterm and term infants. This may be due to inhibition of the distal pathway of cortisol synthesis.

Use of Cortisol and Adrenal Weight at Pediatric Postmortem

We studied the relationship between adrenal weight and postmortem cortisol level in cases of infant death, and examined use of these measurements in adrenal insufficiency. We analyzed procurator-fiscal postmortem reports in the West of Scotland over a three year period. Combined adrenal weight was expressed as percentage of total body weight (%TBW). Of 106 cases, median (5^th, 95^th) %TBW was 0.056 (0.025, 0.23) and median plasma cortisol was 8.4 ug/dl (1.0, 47.1). There was no correlation between %TBW and plasma cortisol (r = 0.09, p = 0.4). The lowest and highest plasma cortisol quartile had medians of 1.9 ug/dl (1.0, 3.4) and 34.3 ug/dl (17.3, 71.5), respectively. Infection was present in 6 cases (23.1%) in the lowest quartile and in 16 cases (61.5%) in the highest quartile (p = 0.01). Our results highlight the difficulty in interpretation of cortisol at postmortem and suggest that adrenal weight measurement alone may be insufficient for diagnosis of adrenal insufficiency.

Hydrocortisone for Treatment of Hypotension in the Newborn

Newborns, and especially premature newborns, are at significant risk for developing hypotension in the first week or two after birth. The etiology of hypotension in the newborn may vary, but the very low birth weight and extremely low birth weight preterm infants are less likely to respond to conventional cardiovascular support when they develop hypotension. This article reviews the least conventional treatment using hydrocortisone for hypotension that is refractory to conventional volume replacement and/or vasopressor medications with the underlying assumption that sick and premature newborns have a relative or measured adrenal insufficiency. The addition of hydrocortisone in the treatment of hypotension in the newborn is becoming more common but is not universally advocated. However, the supportive evidence is growing, and, as reviewed, use of hydrocortisone requires judicious and cautious regard.

Adrenocortical insufficiency and refractory hypotension in preterm infants

Preterm, very low birthweight (VLBW) infants are prone to life-threatening hypotension secondary to hypothalamic-pituitary-adrenal axis immaturity, resulting in adrenocortical insufficiency. Clinical presentations of inotrope-resistant refractory hypotension are usually evident, but interpretation of serum cortisol may pose much difficulty to front-line neonatologists. This review examines the salient pathophysiology of adrenocortical insufficiency in the immediate postnatal period, characterises its endocrinological abnormalities, and describes the typical and variant clinical presentations. Based on existing evidence, a practical scheme is proposed for logical interpretation of circulating cortisol levels and management of inotrope-resistant refractory hypotension in VLBW infants.

Term neonates with infection and shock display high cortisol precursors despite low levels of normal cortisol

AIM

Neonatal therapy-resistant septic shock is a common problem in middle and low-income countries. We investigated whether newborn infants with infection and therapy-resistant hypotension showed evidence of abnormal levels of cortisol or cortisol precursors.

METHODS

A total of 60 term or near term neonates with evidence of infection were enrolled after informed consent. Of these, 30 had an infection and refractory shock and 30 had an infection without shock. There were no detectable differences between the groups in the length of gestation, birth weight or gender distribution. Serum was obtained during days four and 14 after birth. Cortisol and cortisol precursor concentrations were analysed using liquid chromatography-tandem mass spectrometry.

RESULTS

The cortisol concentrations were low considering the expected responses to stress and they did not differ between the groups. The infants with infection and shock had higher serum dehydroepiandrosterone (DHEA) levels than those without shock (319.0 ± 110.3 μg/dL, versus 22.3 ± 18.3 μg/dL; p < 0.0001) and they also had higher 17-hydroxy-pregnenolone, pregnenolone and progesterone concentrations. There were no detectable differences in the levels of 17-hydroxy-progesterone, 11-deoxy-cortisol, cortisol or cortisone.

CONCLUSION

Septic newborn infants with therapy-resistant hypotension had very high DHEA levels, suggesting that 3-beta-hydroxysteroid dehydrogenase activity limited the rate of cortisol synthesis.

Brain disorders associated with corticotropin-releasing hormone expression in the placenta among children born before the 28th week of gestation

AIM

To evaluate the relationship between placenta corticotropin-releasing hormone (CRH) expression and brain structure and function abnormalities in extremely preterm newborns.

METHODS

In a sample of 1243 infants born before the 28th week of gestation, we evaluated the relationship between CRH expression in the placenta and the risk of brain ultrasound scan abnormalities identified while these infants were in the intensive care nursery, low scores on the Bayley Scales of Infant Development-II of 900 of these children at age two years and head circumference measurements then more than one and two standard deviations below the mean.

RESULTS

Infants who had a low placenta CRH messenger ribonucleic acid (mRNA) concentration were at increased risk of ventriculomegaly on an ultrasound scan. An elevated placenta CRH mRNA concentration was associated with increased risk of an inability to walk at age two years, and a Bayley Motor Scale 3 standard deviations below the mean.

CONCLUSION

Placenta CRH mRNA concentration appears to convey information about the risk of brain damage in the infant born at an extremely low gestational age.

Prematurity, Birth Weight, and Socioeconomic Status Are Linked to Atypical Diurnal Hypothalamic-Pituitary-Adrenal Axis Activity in Young Adults

In a prospective, case-controlled longitudinal design, 180 preterm and fullterm infants who had been enrolled at birth participated in a comprehensive assessment battery at age 23. Of these, 149 young adults, 34 formerly full-term and 115 formerly preterm (22 healthy preterm, 48 with medical complications, 21 with neurological complications, and 24 small for gestational age) donated five saliva samples from a single day that were assayed for cortisol to assess diurnal variation of the hypothalamic-pituitary-adrenal (HPA) axis. Analyses were conducted to determine whether prematurity category, birth weight, and socioeconomic status were associated with differences in HPA axis function. Pre- and perinatal circumstances associated with prematurity influenced the activity of this environmentally sensitive physiological system. Results are consistent with the theory of Developmental Origins of Health and Disease and highlight a possible mechanism for the link between prematurity and health disparities later in life.

Hypotension following patent ductus arteriosus ligation: the role of adrenal hormones

OBJECTIVE

To test the hypothesis that an impaired adrenal response to stress might play a role in the hypotension that follows patent ductus arteriosus (PDA) ligation.

STUDY DESIGN

We performed a multicenter study of infants born at <32 weeks' gestation who were about to undergo PDA ligation. Serum adrenal steroids were measured 3 times: before and after a cosyntropin (1.0 μg/kg) stimulation test (performed before the ligation), and at 10-12 hours after the ligation. A standardized approach for diagnosis and treatment of postoperative hypotension was followed at each site. A modified inotrope score (1 × dopamine [μg/kg/min] + 1 × dobutamine) was used to monitor the catecholamine support an infant received. Infants were considered to have catecholamine-resistant hypotension if their greatest inotrope score was >15.

RESULTS

Of 95 infants enrolled, 43 (45%) developed hypotension and 14 (15%) developed catecholamine-resistant hypotension. Low postoperative cortisol levels were not associated with the overall incidence of hypotension after ligation. However, low cortisol levels were associated with the refractoriness of the hypotension to catecholamine treatment. In a multivariate analysis: the OR for developing catecholamine-resistant hypotension was OR 36.6, 95% CI 2.8-476, P = .006. Low cortisol levels (in infants with catecholamine-resistant hypotension) were not attributable to adrenal immaturity or impairment; their cortisol precursor concentrations were either low or unchanged, and their response to cosyntropin was similar to infants without catecholamine-resistant hypotension.

CONCLUSION

Infants with low cortisol concentrations after PDA ligation are likely to develop postoperative catecholamine-resistant hypotension. We speculate that decreased adrenal stimulation, rather than an impaired adrenal response to stimulation, may account for the decreased production.

Dopamine-resistant hypotension and severe retinopathy of prematurity

OBJECTIVE

To examine the relationship between the cause or severity of hypotension and the development of severe ROP (sROP) (≥stage 3 or stage 2 with plus disease in zone I or II).

STUDY DESIGN

Infants (<28 weeks' gestation, n = 242) were observed for hypotension and treated with a standardized hypotension-treatment protocol. Hypotension was classified as resulting from one of the following causes: (1) culture-positive infection and/or necrotizing enterocolitis; (2) patent ductus arteriosus ligation; or (3) "idiopathic" (no cause identified other than prematurity), and as being either dopamine responsive or dopamine resistant. Cortisol levels were measured for infants with dopamine-resistant hypotension. Eye examinations were performed until the retinopathy of prematurity resolved or the vasculature matured. Multivariable logistic regression analysis was performed to determine the relationship between the cause/severity of hypotension and sROP.

RESULTS

Overall, 66% of infants developed hypotension (41% were dopamine responsive and 25% were dopamine resistant). sROP developed in 19% of infants. "Idiopathic" dopamine-resistant hypotension was the only cause significantly related to sROP. Of the infants with dopamine-resistant hypotension, 66% had low serum cortisol (≤10 μg/dL). Low cortisol, in the presence of dopamine-resistant hypotension, was significantly associated with sROP and accounted for the relationship between "idiopathic" hypotension and sROP. When low cortisol was included in statistical models, other known risk factors, such as immature gestation, were no longer significantly related to sROP.

CONCLUSION

Low cortisol, in the presence of dopamine-resistant hypotension, has the greatest magnitude of association with sROP.

Cardiovascular instability after patent ductus arteriosus ligation in preterm infants: the role of hydrocortisone

OBJECTIVE

Following patent ductus arteriosus (PDA) ligation, preterm infants may develop profound hypotension and respiratory failure. Prophylactic stress hydrocortisone (HC) has emerged as a therapy to prevent complications, postulating these infants do not synthesize steroids because of an immature hypothalamic-pituitary-adrenal axis. The purpose of this study was to compare outcomes in infants who received stress HC before their PDA ligations to those who did not.

STUDY DESIGN

A retrospective chart review was performed of infants who underwent PDA ligations at our institution's neonatal intensive care unit. Data were collected on treatment with HC, and respiratory and cardiovascular support.

RESULT

Gestational age (GA) and birth weight were lower in the HC group (24 vs 25 weeks, 632 vs 790 g), but age at time of surgery was similar (26 vs 21 days). Cardiorespiratory support was comparable between the groups pre- and post-operatively. In regression models that adjusted for GA, HC treatment was not independently related to respiratory support postoperatively, but was associated with a decrease in postoperative dopamine (2.2 mcg kg(-1)  min(-1); P=0.03). Respiratory support postoperatively was predicted by preoperative respiratory support. GA and age at surgery were not independently associated with outcome.

CONCLUSION

Preoperative stress HC was not associated with improved cardiorespiratory stability, regardless of GA. Further investigation is needed to identify infants who may benefit from this therapy.

The use of an early ACTH test to identify hypoadrenalism-related hypotension in low birth weight infants

OBJECTIVE

To investigate if in preterm newborns, an early adrenocorticotropin hormone (ACTH) test can identify possible transient adrenal insufficiency (TAI), using significant hypotension as a clinical marker.

STUDY DESIGN

We studied 40 premature newborns born 24 to 29 weeks gestational age (GA) before 8 h of life. Serum cortisol levels were obtained before and 40 min after administration of 1.0 mcg kg(-1) cosyntropin. Inotropes were used to treat hypotension based on clinical assessment following no response to fluid boluses. Functional echocardiogram was used to support the clinical diagnosis of hypotension. The accuracy of the ACTH test was evaluated using receiver operating characteristic (ROC) curve.

RESULT

Study patients had mean GA of 26.6 weeks and birth weight of 876 g. In all, 30% required inotropes. The area under the ROC curve for the ACTH test was 87%. Using a cutoff of an increase in cortisol below 12% from baseline had 75% sensitivity and 93% specificity for detecting hypotension. This cutoff was associated with bronchopulmonary dysplasia (8/12 vs 7/28, 95% CI: 0.1 to 0.72), but not with other morbidities or death.

CONCLUSION

An early ACTH test using the above cutoff has high specificity for detecting hypotension, and thus, can serve as a marker for potential TAI in preterm newborns. Future studies should focus on identifying those newborns for which steroid supplementation would be most beneficial.

Diagnostic value of salivary cortisol in the CRH stimulation test in premature infants

CONTEXT

According to a recent nationwide survey in Japan, a significant proportion of very low birth weight infants (VLBWI) develop late-onset circulatory collapse after the first week of life. Small doses of glucocorticoid are very effective in these patients, and relative adrenal insufficiency is suspected to be the main cause of the condition. Although the CRH test is required to evaluate the hypothalamic-pituitary-adrenal axis, obtaining multiple blood samples is invasive.

OBJECTIVES

The present study was carried out to validate the consistency of the cortisol profiles of matched serum and saliva samples collected as part of the CRH test from VLBWI.

SUBJECTS/METHODS

In 23 VLBWI with a gestational age of less than 29 wk, we performed CRH tests at 2 wk after birth and at term. Their cortisol values were measured at the baseline and 30 min after the administration of a single dose of human CRH (1 μg/kg) using matched serum and saliva samples.

RESULTS

In 26 CRH tests in 19 infants, we were able to measure both serum and salivary cortisol. Significant correlations were detected between the infants' serum and salivary cortisol values (r=0.78; P<0.0001), the increases in these values induced in response to the CRH test (r=0.81; P<0.0001), and their peak serum and salivary cortisol values (r=0.68; P=0.0001).

CONCLUSION

This study indicated that using salivary cortisol measurements for the CRH test could be a reliable method for evaluating the hypothalamic-pituitary-adrenal axis in VLBWI with gestational age of less than 29 wk.

Lack of renal 11 beta-hydroxysteroid dehydrogenase type 2 at birth, a targeted temporal window for neonatal glucocorticoid action in human and mice

Background

Glucocorticoid hormones play a major role in fetal organ maturation. Yet, excessive glucocorticoid exposure in utero can result in a variety of detrimental effects, such as growth retardation and increased susceptibility to the development of hypertension. To protect the fetus, maternal glucocorticoids are metabolized into inactive compounds by placental 11beta-hydroxysteroid dehydrogenase type2 (11βHSD2). This enzyme is also expressed in the kidney, where it prevents illicit occupation of the mineralocorticoid receptor by glucocorticoids. We investigated the role of renal 11βHSD2 in the control of neonatal glucocorticoid metabolism in the human and mouse.

Methods

Cortisol (F) and cortisone (E) concentrations were measured in maternal plasma, umbilical cord blood and human newborn urine using HPLC. 11βHSD2 activity was indirectly assessed by comparing the F/E ratio between maternal and neonatal plasma (placental activity) and between plasma and urine in newborns (renal activity). Direct measurement of renal 11βHSD2 activity was subsequently evaluated in mice at various developmental stages. Renal 11βHSD2 mRNA and protein expression were analyzed by quantitative RT-PCR and immunohistochemistry during the perinatal period in both species.

Results

We demonstrate that, at variance with placental 11βHSD2 activity, renal 11βHSD2 activity is weak in newborn human and mouse and correlates with low renal mRNA levels and absence of detectable 11βHSD2 protein.

Conclusions

We provide evidence for a weak or absent expression of neonatal renal 11βHSD2 that is conserved among species. This temporal and tissue-specific 11βHSD2 expression could represent a physiological window for glucocorticoid action yet may constitute an important predictive factor for adverse outcomes of glucocorticoid excess through fetal programming.

Perinatal endocrinology: common endocrine disorders in the sick and premature newborn

Endocrine disorders are common in infants in the neonatal ICU. They often are associated with prematurity, low birth weight or very low birth weight, and small size for gestational age. They also frequently occur in infants who are critically ill or stressed. This article describes the most common conditions and current knowledge regarding management.

A prospective longitudinal study to estimate the "adjusted cortisol percentile" in preterm infants

The normal range of serum cortisol concentrations and the appropriate levels of circulating cortisol in different clinical situations in preterm infants are not well defined. This study aimed to evaluate the impact of perinatal factors on circulating cortisol levels in preterm infants and to create a quantitative model that could estimate the "adjusted cortisol percentile." Serial serum cortisol concentrations were measured in 209 infants ≤ 32 wk gestation on d 1, 4, 7, 14, and 21 of life. Seven perinatal factors or conditions that could affect circulating cortisol level were identified. Serum cortisol levels were higher on d 4 (p = 0.007) and d 7 (p = 0.007) but lower on d 21 (p = 0.001) compared with d 1. Serum cortisol was also higher in infants on nasal continuous positive airway pressure (p = 0.003); requiring a second vasopressor (p < 0.001); with intraventricular hemorrhage (≥ grade 3; p < 0.001); with histologic chorioamnionitis (p = 0.007); with severe lung disease (p = 0.046); and with decreasing GA (p < 0.001). A mathematical equation was proposed based on factors derived in this preliminary study for estimating the adjusted cortisol percentile. Frontline neonatologists could now access the equation on our Web site (http://www.sta.cuhk.edu.hk/pswong/ACortP.html) to calculate the adjusted cortisol percentile, which could potentially improve the interpretation of circulating cortisol in different clinical situations.

Bronchopulmonary Dysplasia: Development and Progression in the Neonatal Intensive Care Unit

Advances in neonatology have led to increased survival at younger gestational ages. These advances have included the ability to provide and titrate oxygen, improved modalities of assisted ventilation, improved nutritional and environmental support, and surfactant therapy. As a result of increasing survival of these immature infants, bronchopulmonary dysplasia (BPD) has become a consistent outcome despite improvements in technology. Varying definitions of BPD have emerged in an effort to best identify infants at risk for long-term adverse outcome and those who might benefit most from preventive therapies. Underlying abnormal pulmonary development of extremely preterm infants in the face of exposure to oxygen, assisted ventilation and inflammation make this a complex, multifactorial disease. Recent focus has been directed at preventing and treating inflammation. Efforts to minimize the inflammatory process include avoiding hyperoxia, minimizing injury from assisted ventilation, and preventing and treating postnatal infections. Additional therapies to modulate inflammation, such as steroid therapy or inhaled nitric oxide, need further investigation of both short- and long-term outcomes before routine use can be recommended.

Effect of stress on the hypothalamic-pituitary-adrenal axis in the fetus and newborn

The hypothalamic-pituitary-adrenal (HPA) axis is essential for maintaining homeostasis in the fetus and newborn. A proportion of extremely preterm infants suffer from transient adrenocortical insufficiency of prematurity. Although these infants have suboptimal adrenocortical response to stress in the first week of life, the HPA axis adapts rapidly, and most exhibit an adequate response by day 14. An attenuated cortisol response in preterm infants might be protective against intracranial bleeding. Severe hypoxic-ischemic encephalopathy is a potent stimulus to the HPA axis. Chronic intrauterine hypoxemia can up-regulate the setpoint of the HPA axis and augments adrenal steroidogenic production, resulting in sustained elevation of circulating cortisol levels.

Judicious use of antenatal glucocorticoids: putting the risks into the balance

The administration of a course of antenatal glucocorticoids (AG) to improve neonatal outcome after preterm birth is a prime example of evidence-based medicine, but the current clinical application of AG is too broad. AG override the glucocorticoid enzymatic placental barrier in order to elicit fetal lung maturation at a pre-physiological gestational age. Yet the maturation benefit is accompanied by a number of undesirable phenomena, most of which are transient (lasting for at least 24-48 h after the last injection). These include metabolic effects in both mother and fetus and signs of reduced fetal wellbeing. In addition, the fetal growth rate slows down depending on the number of AG courses. Multiple courses may increase the risk of cerebral palsy, as neonatal dexamethasone treatment does. There are no randomised trials on the benefit-risk balance of AG in pregnancies complicated by diabetes or intra-uterine growth restriction (IUGR). Animal studies indicate that AG are associated with an inadequate response to acute hypoxaemia and different brain development. Judicious use of AG includes avoidance of multiple courses, and a case-based -approach in pregnancies with (pre)gestational diabetes, IUGR or equivocal fetal condition, until more data become available. In addition, better prediction models of preterm birth are needed.

Serum cortisol values, superior vena cava flow and illness severity scores in very low birth weight infants

OBJECTIVE

Recent evidence suggests that high cortisol concentrations are associated with increased morbidity and mortality in very low birth weight (VLBW) infants. Neonatal illness severity and mortality risk scores are reliable in predicting morbidity and mortality. The objectives were (i) to assess the correlation between serum cortisol levels and clinical assessment of multi-organ dysfunction/illness severity scores (CRIB II, SNAPPE-II and neonatal multiple organ dysfunction score (NEOMOD)) in first 24 h in VLBW infants and (ii) to assess the relationship between surrogates of end organ blood flow and serum cortisol levels.

STUDY DESIGN

A prospective observational cohort study. Neonates with birth weight <1500 g were eligible for enrollment. Echocardiography evaluation of superior vena cava (SVC) flow was carried out in the first 24 h life. Cortisol levels were measured simultaneously and appropriate clinical scores were calculated.

RESULT

A total of 54 VLBW neonates were enrolled following parental consent. Two patients were excluded because of congenital malformations. In 14 babies the cortisol value was not simultaneously obtained. The mean birth weight was 1.08 kg, mean gestational age was 27.8 weeks. There was a significant correlation between cortisol and NEOMOD score (P=0.006). There was no correlation between cortisol and CRIB II score (P=0.34), SVC flow (P=0.49) and mean arterial blood pressure respectively (P=0.35).

CONCLUSION

There was no correlation between SVC flow and cortisol values or between cortisol and mean blood pressure values. There was a significant correlation between cortisol levels and neonatal organ dysfunction score evaluated suggesting that stressed VLBW infants do mount a cortisol response.

Early cortisol values and long-term outcomes in extremely low birth weight infants

OBJECTIVE

Both excess and insufficient levels of glucocorticoid in extremely low birth weight (ELBW) infants have been associated with adverse hospital outcomes, whereas excess glucocorticoid exposure has been associated with long-term adverse neurodevelopment. Our objective was to evaluate the relationship between neonatal cortisol concentrations and long-term outcomes of growth and neurodevelopment.

STUDY DESIGN

As part of a multicenter randomized trial of hydrocortisone treatment for prophylaxis of relative adrenal insufficiency, cortisol concentrations were obtained at 12 to 48 h of postnatal age and at days 5 to 7 on 350 intubated ELBW infants, of whom 252 survived and returned for neurodevelopmental follow-up at 18 to 22 months corrected age. Cortisol values from each time point were divided into quartiles. Growth and neurodevelopmental outcome were compared for each quartile.

RESULT

Median cortisol value was 16.0 microg per 100 ml at baseline for all infants, and 13.1 microg per 100 ml on days 5 to 7 in the placebo group. Outcomes did not differ in each quartile between treatment and placebo groups. Low cortisol values at baseline or at days 5 to 7 were not associated with impaired growth or neurodevelopment at 18 to 22 months corrected age. High cortisol values were associated with an increase in cerebral palsy, related to the increased incidence of severe intraventricular hemorrhage (IVH) and periventricular leukomalacia.

CONCLUSION

Low cortisol concentrations were not predictive of adverse long-term outcomes. High cortisol concentrations, although predictive of short-term adverse outcomes such as IVH and periventricular leukomalacia, did not additionally predict adverse outcome. Further analysis into identifying factors that modulate cortisol concentrations shortly after birth could improve our ability to identify those infants who are most likely to benefit from treatment with hydrocortisone.

Adrenal insufficiency in newborns with congenital diaphragmatic hernia

Newborns with congenital diaphragmatic hernia frequently have catecholamine-unresponsive systemic hypotension and respiratory failure. We found that adrenal insufficiency frequently complicates the clinical course of infants with congenital diaphragmatic hernia and was associated with increased severity of illness.

Transient adrenal insufficiency in the premature newborn

PURPOSE OF REVIEW

Relative adrenal insufficiency is a controversial phenomenon described in adults and children with critical illness, especially septic shock. In the past 2 decades, relative adrenal insufficiency has also been reported in the critically ill premature as well as term newborn. The present study will review the initial and more recent studies addressing adrenal insufficiency in the premature infant.

RECENT FINDINGS

Studies suggest that 'relative adrenal insufficiency' is a contributing factor to hemodynamic instability in the sick preterm newborn. Many ill preterm newborns have inappropriately low serum cortisol concentrations and respond to steroid administration. Adrenal insufficiency is transient and likely reflects normal adrenal physiology at younger gestational ages. There is no general consensus on its diagnosis, effective minimum dose for treatment and duration of treatment.

SUMMARY

More large scale, multicenter, randomized, double-blind studies are needed to make the diagnosis of relative adrenal insufficiency and to determine the indication, dose, complications and outcome of glucocorticoid therapy.

Perinatal endocrinology: common endocrine disorders in the sick and premature newborn

Endocrine disorders are common in infants in the neonatal ICU. They often are associated with prematurity, low birth weight or very low birth weight, and small size for gestational age. They also frequently occur in infants who are critically ill or stressed. This article describes the most common conditions and current knowledge regarding management.