The Association between Maternal Stress and Glucocorticoid Rhythmicity in Human Milk.

BACKGROUND: Chronic stress is often accompanied by alterations in the diurnal rhythm of hypothalamus-pituitary-adrenal activity. However, there are limited data on the diurnal rhythmicity of breast milk glucocorticoids (GCs) among women with psychological distress. We compared mothers who sought consultation at an expertise center for pregnant women with an increased risk of psychological distress with control mothers for GC diurnal rhythmicity in milk and saliva obtained at the same time. METHODS: We included 19 mothers who sought consultation at the psychiatry-obstetric-pediatric (POP) outpatient clinic and 44 control mothers. One month postpartum, mothers collected on average eight paired milk and saliva samples during a 24 h period. GC levels were measured using liquid chromatography-tandem mass spectrometry. GC rhythmicity parameters were determined with specialized software. RESULTS: For both milk and saliva, no group differences regarding GC rhythms were found. Milk cortisol area under the curve with respect to the ground was lower in the POP group than in the control group (p = 0.02). GC levels in human milk and saliva were highly correlated within each group (p < 0.001). CONCLUSION: Although there were no differences between groups in GC rhythmicity, the total amount of milk cortisol was lower in the POP group. Long-term follow-up is needed to address the impact of vertical transmission of breast milk GCs.

Diurnal rhythmicity in breast-milk glucocorticoids, and infant behavior and sleep at age 3 months.

PURPOSE: In previous studies, associations between breast-milk cortisol levels obtained on one occasion and infant neurodevelopment were demonstrated. However, more recent evidence indicates that breast-milk cortisol and cortisone concentrations follow the diurnal rhythm of maternal hypothalamus-pituitary-adrenal axis, peaking in the early morning and with a nadir at midnight. We studied associations between breast-milk glucocorticoid (GC) rhythmicity, and infant behavior and sleep. METHODS: We included 59 mothers, and their infants, of whom 17 had consulted an expert center during pregnancy for an increased risk of psychological distress. At 1 month postpartum, breast milk was sampled (on average six times) over a 24 h period for assessment of cortisol and cortisone using LC-MS/MS, and experienced maternal distress was assessed using the Hospital Anxiety and Depression Scale questionnaire. Three months after birth, infant behavior was assessed with the Infant Behavior Questionnaire, and infant sleep pattern was quantified by questionnaire. Associations between breast-milk GC rhythm parameters (maximum, delta, and Area Under the Curve increase and ground) and infant behavior and sleep were tested with linear regression analyses. RESULTS: No consistent associations between breast-milk GC rhythm parameters and infant behavior or sleep were found. CONCLUSIONS: Breast-milk GC rhythmicity at 1 month postpartum was not associated with infant behavior or sleep at the age of 3 months. Findings from previous studies linking breast-milk cortisol to infant neurodevelopment might be biased by the lack of GC measurements across the full diurnal cycle, and should therefore be interpreted with caution.

Biphasic Glucocorticoid Rhythm in One-Month-Old Infants: Reflection of a Developing HPA-Axis?

CONTEXT: The hypothalamus-pituitary-adrenal (HPA) axis displays a diurnal rhythm. However, little is known about its development in early life. OBJECTIVE: To describe HPA-axis activity and study possible influencing factors in 1-month-old infants. DESIGN: Observational. SETTING: Amsterdam University Medical Center, location VU University Medical Center (VUMC), and Onze Lieve Vrouwe Gasthuis (OLVG), Amsterdam. PARTICIPANTS: Fifty-five mother-infant pairs. INTERVENTIONS: Collection of breast milk and infants' saliva 1 month postpartum for analysis of glucocorticoids (GCs; ie, cortisol and cortisone) using liquid chromatography- tandem mass spectrometry. MAIN OUTCOME MEASURE: GC rhythm in infants' saliva and associations with vulnerability for maternal psychological distress (increased Hospital Anxiety and Depression Scale [HADS] score) or consultation at the Psychiatric Obstetric Pediatric (POP clinic), season at sampling, sex, and breast milk GC rhythmicity analyzed with SigmaPlot 14.0 software (Systat Software, San Jose, CA, USA) and regression analyses. RESULTS: A significant biphasic GC rhythm was detected in infants, with mean peaks [standard error of the mean, SEM] at 6:53 am [1:01] and 18:36 pm [1:49] for cortisol, and at 8:50 am [1:11] and 19:57 pm [1:13] for cortisone. HADS score, POP consultation, season at sampling, and sex were not associated with the infants' GC rhythm. Breast milk cortisol maximum was positively associated with infants' cortisol area-under-the-curve (AUC) increase and maximum. Higher breast milk cortisone AUC increase, AUC ground, and maximum were associated with an earlier maximum in infants. Breast milk and infant GC concentrations were associated between 6:00 am and 9:00 am. CONCLUSIONS: A biphasic GC rhythm, peaking in the morning and evening, was seen in 1-month-old infants at a group level. Breast milk GC parameters might be associated with the infants' GC rhythm, possibly caused by a signaling effect of breast milk GCs, or as an associative effect of increased mother-infant synchrony. These results contribute to an increased understanding of early life HPA-axis development.

Long-Term Neurodevelopmental and Functional Outcomes of Infants Born Very Preterm and/or with a Very Low Birth Weight.

BACKGROUND: Birth weight (BW) is often used as a proxy for gestational age (GA) in studies on preterm birth. Recent findings indicate that, in addition to perinatal outcomes, subjects born very preterm (VP; GA < 32 weeks) differ from those with a very low birth weight (VLBW; BW < 1,500 g) in postnatal growth up to their final height. OBJECTIVE: To study whether neurodevelopmental and functional outcomes at the age of 19 years differ in VP and/or VLBW subjects. METHODS: 705 19-year-old subjects from the Project on Preterm and Small-for-Gestational-Age Infants (POPS) cohort were classified as (1) VP+/VLBW+ (n = 354), (2) VP+/VLBW- (n = 144), or (3) VP-/VLBW+ (n = 207), and compared with regard to IQ as assessed with the Multicultural Capacity Test-intermediate level; neuromotor function using Touwen's examination of mild neurologic dysfunction; hearing loss; self- and parent-reported behavioral and emotional functioning; educational achievement and occupation; and self-assessed health using the Health Utilities Index and the London Handicap Scale. RESULTS: VP+/VLBW- infants, on average, had 3.8-point higher IQ scores (95% confidence interval [CI] 0.5-7.1), a trend towards higher educational achievement, 3.3-dB better hearing (95% CI 1.2-5.4), and less anxious behavior, attention problems, and internalizing behavior than to VP+/VLBW+ subjects. VP-/VLBW+ infants reported 1.8 increased odds (95% CI 1.2-2.6) of poor health compared to VP+/VLBW+ subjects. CONCLUSIONS: At the age of 19 years, subjects born VP+/VLBW+, VP+/VLBW-, and VP-/VLBW+ have different neurodevelopmental and functional outcomes, although effect sizes are small. Hence, the terms VP and VLBW are not interchangeable. We recommend, at least for industrialized countries, to base inclusion in future studies on preterm populations on GA instead of on BW.

The Association between Breastmilk Glucocorticoid Concentrations and Macronutrient Contents Throughout the Day.

BACKGROUND: Glucocorticoids (GCs) in breastmilk follow the maternal hypothalamus⁻pituitary⁻adrenal axis activity and may affect the offspring's growth and neurodevelopment. There is some evidence suggesting that macronutrients in breastmilk also fluctuate throughout the day. We aimed to research whether GCs and macronutrients are correlated in multiple breastmilk samples obtained over a 24-h period. METHODS: A total of 10 mothers provided 45 breastmilk samples collected over a 24-h period. Cortisol and cortisone levels were determined by LC⁻MS/MS, and macronutrients were measured with mid-infrared spectroscopy. Correlations between breastmilk GCs and macronutrients were assessed with Pearson correlations and linear mixed models. RESULTS: No associations were found between breastmilk GCs and macronutrients (cortisol: ß-0.1 (95% confidence interval: -1.0 to 0.7), -4.9 (-12.9 to 3.1) for fat, protein, and carbohydrates, respectively; and -0.3 (-5.6 to 5.0) and cortisone: 0.0 (-2.5 to 2.5), -17.4 (-39.8 to 5.0), and -2.7 (-17.7 to 12.3)) for fat, protein, and carbohydrates, respectively. Adjusting for the time of collection to account for GC rhythmicity did not change the results. CONCLUSION: We found no associations between GCs and macronutrients in human breastmilk. The excretion of GCs in breastmilk and the effects of breastmilk GCs on offspring are, therefore, likely independent of the excretion and effects of the macronutrients.

Early-life growth of preterm infants and its impact on neurodevelopment.

BACKGROUND: Increasing numbers of preterm-born children survive nowadays, and improving long-term health and neurodevelopment is becoming more important. Early-life growth has been linked to neurodevelopmental outcomes. We aimed to study whether this association has changed with time. METHODS: We studied two cohorts of preterm-born children (gestational age ≤32 weeks and/or birth weight ≤1500 g) from 1983 (n = 708) and 2003-2006 (n = 138), respectively. We distinguished four early-life growth patterns at 3 months corrected age: appropriate for gestational age (AGA) with or without growth restriction (AGA GR+/AGA GR-), and small for gestational age (SGA) with or without catch-up growth (SGA CUG+/SGA CUG-). Intelligence quotient (IQ), neuromotor function, and behavior were assessed at ages 19 and 8 years, respectively, for the cohorts. RESULTS: In the 2003-2006 cohort, less children had early-life GR. In both cohorts, SGA CUG- subjects had unfavorable growth trajectories and neurodevelopmental outcomes (IQ ß -6.5, 95% confidence interval (CI) -9.8; -3.2, P < 0.001; neuromotor score ß -1.9%, 95% CI -3.2; -0.6, P = 0.005), while SGA CUG+ subjects were comparable to adequately grown subjects. CONCLUSION: Although the incidence of adverse growth patterns decreased between the cohorts, possibly indicating improvements in care over time, the impact of these growth patterns on neurodevelopmental outcomes was not significantly different. Achieving adequate early-life growth may be crucial for improving neurodevelopmental outcomes, especially for preterms born SGA.

Maternal Stress During Pregnancy Is Associated with Decreased Cortisol and Cortisone Levels in Neonatal Hair.

BACKGROUND: Hair glucocorticoids (GCs) offer a retrospective view on chronic GC exposure. We assessed whether maternal pre- and postnatal stress was associated with neonatal and maternal hair GCs postpartum (pp). METHODS: On the first day pp 172 mother-infant pairs donated hair, of whom 67 had consulted a centre of expertise for psychiatric disorders during pregnancy. Maternal stress was scored on the Hospital Anxiety and Depression Scale during the first/second (n = 46), third trimester (n = 57), and pp (n = 172). Hair cortisol and cortisone levels were determined by liquid chromatography-tandem mass spectrometry, and associations with maternal hospital anxiety subscale (HAS) and hospital depression subscale (HDS) scores, and antidepressant use were analyzed with linear regression. RESULTS: Neonatal hair GCs were negatively associated with elevated HAS-scores during the first/second trimester, log 10 (ß [95% CI]) cortisol -0.19 (-0.39 to 0.02) p = 0.07, cortisone -0.10 (-0.25 to 0.05) p = 0.17; third trimester, cortisol -0.17 (-0.33 to 0.00) p = 0.05, cortisone -0.17 (-0.28 to -0.05) p = 0.01; and pp, cortisol -0.14 (-0.25 to -0.02) p = 0.02, cortisone -0.07 (-0.16 to 0.02) p = 0.10. A similar pattern was observed for elevated HDS-scores. Maternal hair GCs were positively associated with elevated HAS-scores pp (cortisol 0.17 [0.01 to 0.32] p = 0.04, cortisone 0.18 [0.06 to 0.31] p = 0.01), but not prenatally or with elevated HDS-scores. Antidepressant use was associated with elevated maternal hair GCs (p ≤ 0.05), but not with neonatal hair GCs. CONCLUSION: Exposure to excessive pre- and perinatal maternal stress was associated with a decrease in neonatal hair GCs, while elevated stress-scores around birth were associated with increased maternal hair GCs and elevated stress-scores earlier in gestation were not associated with maternal hair GCs pp. Further studies are needed to test associations with infant neurodevelopment.

Nutritional programming by glucocorticoids in breast milk: Targets, mechanisms and possible implications.

Vertical transmission of glucocorticoids via breast milk might pose a mechanism through which lactating women could prepare their infants for the postnatal environment. The primary source of breast-milk glucocorticoids is probably the systemic circulation. Research from our group showed that milk cortisol and cortisone concentrations follow the diurnal rhythm of maternal hypothalamus-pituitary-adrenal axis activity, with a higher abundance of cortisone compared to cortisol. Measurement of breast-milk glucocorticoid concentrations is challenging due to possible cross-reactivity with progestagens and sex steroids, which are severely elevated during pregnancy and after parturition. This requires precise methods that are not hindered by cross reactivity, such as LC-MS/MS. There are some data suggesting that breast-milk glucocorticoids could promote intestinal maturation, either locally or after absorption into the systemic circulation. Breast-milk glucocorticoids might also have an effect on the intestinal microbiome, although this has not been studied thus far. Findings from studies investigating the systemic effects of breast-milk glucocorticoids are difficult to interpret, since none took the diurnal rhythm of glucocorticoids in breast milk into consideration, and various analytical methods were used. Nevertheless, glucocorticoids in breast milk might offer a novel potential pathway for signal transmission from mothers to their infants.

Interpretation of glucocorticoids in neonatal hair: a reflection of intrauterine glucocorticoid regulation?

BACKGROUND: Glucocorticoids (GCs) measured in neonatal hair might reflect intrauterine as well as postpartum GC regulation. We aimed to identify factors associated with neonatal hair GC levels in early life, and their correlation with maternal hair GCs. METHODS: In a single-center observational study, mother-infant pairs (n = 107) admitted for >72 h at the maternity ward of a general hospital were included. At birth and an outpatient visit (OPV, n = 72, 44 ± 11 days postpartum), maternal and neonatal hair was analyzed for cortisol and cortisone levels by LC-MS/MS. Data were analyzed regarding: (1) neonatal GC levels postpartum and at the OPV, (2) associations of neonatal GC levels with maternal GC levels and (3) with other perinatal factors. RESULTS: (1) Neonatal GC levels were >5 times higher than maternal levels, with a decrease in ±50% between birth and the OPV for cortisol. (2) Maternal and neonatal cortisol, but not cortisone, levels were correlated both at postpartum and at the OPV. (3) Gestational age was associated with neonatal GC postpartum (log-transformed ß (95% CI): cortisol 0.07 (0.04-0.10); cortisone 0.04 (0.01-0.06)) and at the OPV (cortisol 0.08 (0.04-0.12); cortisone 0.00 (-0.04 to 0.04)), while weaker associations were found between neonatal GCs and other perinatal and maternal factors. CONCLUSIONS: Neonatal hair GCs mainly reflect the third trimester increase in cortisol, which might be caused by the positive feedback loop, a placenta-driven phenomenon, represented by the positive association with GA. Between birth and 1.5 months postpartum, neonatal hair cortisol concentrations decrease sharply, but still appear to reflect both intra- and extrauterine periods.

Is HPA axis reactivity in childhood gender-specific? A systematic review.

BACKGROUND: In adults, hypothalamus-pituitary-adrenal (HPA) axis activity shows sexual dimorphism, and this is thought to be a mechanism underlying sex-specific disease incidence. Evidence is scarce on whether these sex differences are also present in childhood. In a meta-analysis, we recently found that basal (non-stimulated) cortisol in saliva and free cortisol in 24-h urine follow sex-specific patterns. We explored whether these findings could be extended with sex differences in HPA axis reactivity. METHODS: From inception to January 2016, PubMed and EMBASE.com were searched for studies that assessed HPA axis reactivity in healthy girls and boys aged ≤18 years. Articles were systematically assessed and reported in the categories: (1) diurnal rhythm, (2) cortisol awakening response (CAR), (3) protocolled social stress tests similar or equal to the Trier Social Stress Test for children (TSST-C), (4) pharmacological (ACTH and CRH) stress tests, and (5) miscellaneous stress tests. RESULTS: Two independent assessors selected 109 out of 6158 records for full-text screening, of which 81 studies (with a total of 14,591 subjects) were included. Studies showed that girls had a tendency towards a more variable diurnal rhythm (12 out of 29 studies), a higher CAR (8 out of 18 studies), and a stronger cortisol response to social stress tests (9 out of 21 studies). We found no evidence for sex differences in cortisol response after a pharmacological challenge or to miscellaneous stress tests. DISCUSSION: Sex differences in HPA axis reactivity appear to be present in childhood, although evidence is not unequivocal. For a better evaluation of sex differences in HPA axis reactivity, standardization of protocols and reports of stress tests is warranted.

Growth pattern and final height of very preterm vs. very low birth weight infants.

BackgroundBoth very preterm (VP; i.e., gestational age <32 weeks) and very low birth weight (VLBW; i.e., birth weight <1,500 g) are used as inclusion criteria by studies on preterm birth. We aimed to quantify the impact of these entities on postnatal growth until final height.MethodsSubjects born VP and/or with VLBW from the Project On Preterm and Small-for-gestational-age infants cohort were classified as follows: (1) VP+/VLBW+ (n=495), (2) VP+/VLBW- (n=207), or (3) VP-/VLBW+ (n=296) infants. Anthropometric data were collected at birth, 3, 6, 12, and 24 months' corrected age, and at 5 and 19 years. At 19 years, 590/998 (59%) of the subjects enrolled in 1983 were followed up.ResultsBirth size was smallest in the VP-/VLBW+ group compared with the VP+/VLBW+ and VP+/VLBW- groups. During childhood, length, weight, and head circumference SD scores increased in the VP-/VLBW+ group, whereas SD scores in the VP+/VLBW+ and VP+/VLBW- groups either remained stable or decreased. Despite catch-up growth, VP-/VLBW+ infants remained the shortest and lightest at age 19.ConclusionClassification on the basis of VP and VLBW impacts growth, causing different growth patterns for infants born VP+/VLBW+, VP+/VLBW-, or VP-/VLBW+. For future studies, we recommend, at least for industrialized countries, including preterm infants based on gestational age.

Programming of the Hypothalamus-Pituitary-Adrenal Axis by Very Preterm Birth.

BACKGROUND: Many very preterm (i.e., <32 weeks of gestation) newborns fail to mount an adequate adrenocortical response to stress or illness, termed relative adrenal insufficiency. Conversely, later in life these infants show features of increased glucocorticoid bioactivity, such as abdominal adiposity, insulin resistance, raised blood pressure, shorter stature and internalizing problem behavior. SUMMARY: Studies suggested that very preterm newborns have impairments along multiple levels of the hypothalamus-pituitary-adrenal (HPA) axis. Among the impairment were defects in: (1) the pituitary responsiveness to exogenous corticotropin-releasing hormone, (2) 11ß-hydroxylase activity, and (3) the interconversion between cortisol and inert cortisone. There is some evidence suggesting that later in life these infants have an increased basal secretion rate of cortisol and adrenal hyperandrogenism. However, the response to acute (psychosocial) stress was blunted rather than enhanced in them. The mechanisms explaining this switch in HPA axis activity are complex and not yet fully understood. Key Messages: Very preterm newborns have several impairments along the HPA axis that could impede an adequate adrenocortical response to stress or illness. Later in life, these infants are predisposed to increased HPA axis activity, which could partially explain their phenotype.

Gender-specific differences in hypothalamus-pituitary-adrenal axis activity during childhood: a systematic review and meta-analysis.

BACKGROUND: Gender-specific differences in hypothalamus-pituitary-adrenal (HPA) axis activity have been postulated to emerge during puberty. We conducted a systematic review and meta-analysis to test the hypothesis that gender-specific differences in HPA axis activity are already present in childhood. METHODS: From inception to January 2016, PubMed and EMBASE.com were searched for studies that assessed non-stimulated cortisol in serum or saliva or cortisol in 24-h urine in healthy males and females aged ≤18 years. Studies that conform with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement were reported. Standardized mean differences (95% CIs) were calculated and analyzed using fixed-effect meta-analysis stratified for age: <8 years (prepubertal) and 8-18 years (peri-/postpubertal). For comparison, we ran the same analyses using random-effects models. RESULTS: Two independent assessors selected 413 out of 6158 records (7%) for full-text screening, of which 79 articles were included. Of these, 58 (with data on 16,551 subjects) were included in the meta-analysis. Gender differences in cortisol metabolism differed per age group. Boys aged <8 years had 0.18 (0.06; 0.30) nmol/L higher serum and 0.21 (0.05; 0.37) nmol/L higher salivary cortisol levels, while between 8 and 18 years, boys had 0.34 (0.28; 0.40) nmol/L lower serum and 0.42 (0.38; 0.47) nmol/L lower salivary cortisol levels. In 24-h urine, cortisol was consistently higher in boys, being 0.34 (0.05; 0.64) and 0.32 (0.17; 0.47) µg/24 h higher in the <8- and 8-18-year groups, respectively. However, gender-differences in serum cortisol <8 years and between 8 and 18 years were absent when using random-effects models. CONCLUSIONS: Gender differences in cortisol metabolism are already present in childhood, with higher salivary cortisol in boys aged <8 years compared to girls. This pattern was reversed after the age of 8 years. In contrast, the gender-specific difference in cortisol production as assessed through 24-h urine did not change with age. Although differences were small, and analyses of gender differences in serum cortisol were inconclusive, they might contribute to gender-specific origins of health and disease.

Transient hypothyroxinemia of prematurity and problem behavior in young adulthood.

INTRODUCTION: Preterm newborns are at risk of developing transient hypothyroxinemia of prematurity (THoP), which has been associated with subsequent neurodevelopmental impairments. Behavioral outcomes at adult age after THoP have never been reported. AIM: To examine whether there is an association between THoP and problem behavior at young adult age. METHODS: This study was part of the follow-up of 19-year-old subjects born very preterm (i.e., <32 weeks) and/or with a very low birth weight (i.e.,<1500g) from the Project On Preterm and Small-for-gestational-age infants (POPS) cohort. We included 468 subjects of the POPS cohort; of whom 123 had THoP. Thyroxine (T4) concentrations were obtained through the national neonatal screening program for congenital hypothyroidism. THoP was defined as a T4 concentration <-3 SD (approximately 60nmol/L). At age 19, behavior was assessed using the Young Adult Self Report and the Young Adult Behavioral Checklist for parents. RESULTS: THoP was associated with a 1.8 (95% confidence interval (CI): 1.01-3.4) -fold increased odds of self-reported Internalizing behavior, as well as with a 1.9 (95% CI: 1.1-3.1) -fold increased odds of parent-reported Total problem behavior. These relations persisted after correction for demographic and perinatal variables. Similar associations were absent for the other self-reported and parent-reported syndrome and problem scales. CONCLUSIONS: THoP was associated with more internalizing and total problem behavior at age 19. While our observations warrant more awareness of problem behavior in preterm infants, at present, it is unclear whether these associations are causal and screening for THoP does not seem necessary.

No Association Between Transient Hypothyroxinemia of Prematurity and Neurodevelopmental Outcome in Young Adulthood.

CONTEXT: Transient hypothyroxinemia of prematurity (THoP) has been associated with neurodevelopmental impairment in infancy and childhood. It is not known whether these relations persist into adulthood. OBJECTIVE: The objective was to examine whether there is an effect of THoP on intelligence quotient (IQ) score and motor functioning at a young adult age. DESIGN: This study was part of the 19-year follow-up of the Project On Preterm and Small-for-gestational-age birth (POPS) cohort, which included infants born very preterm (ie, <32 wk) and/or with a very low birth weight (ie, <1500 g). SETTING: This was a multicenter study. PATIENTS: There were 398 19-year-old participants of the POPS cohort, of whom 120 had THoP. EXPOSURE: T4 concentrations were obtained through the national neonatal screening program for congenital hypothyroidism. THoP was defined as a total T4 concentration < -3 SD of the daily mean (approximately 60 nmol/L). MAIN OUTCOME MEASURES: Main outcome measures were IQ and motor functioning, measured with the digital Multicultural Capacities Test-Intermediate Level and a revised version of Touwen's examination of minor neurological dysfunction, respectively. RESULTS: THoP was not associated with IQ score (mean difference, 0 [95% confidence interval, -3.8 to 3.8] points) or motor function (mean difference, 0.6 [95% confidence interval, -1.3 to 2.5] points) after adjustment for demographic and perinatal characteristics. CONCLUSIONS: No associations between THoP and neurodevelopmental outcome at age 19 years were found.