Birth weight and postnatal growth in preterm born children are associated with cortisol in early infancy, but not at age 8 years

A Preliminary Study of Correlates of Premature Birth and Their Influence on Cortisol Levels in Young Children

OBJECTIVE

The HPA-axis is programmed during early infancy, but a lot is unknown about the programming of the HPA-axis in prematurely born or small for gestational age (SGA) children. Therefore, the aim of this preliminary study was to investigate the influence of prematurity and variables associated with birth on cortisol levels in young children.

METHODS

Cortisol was measured in a cross-sectional design in 38 premature born participants (<37 weeks of gestation), aged between 3 - 9 years old. Correlates of prematurity (degree of prematurity and birth delivery route) were investigated in relationship with cortisol levels with regression analysis.

RESULTS

Corrected for sex, delivery by C-section was associated with lower cortisol levels in the children (ß = -.42, p = .028), with an explained variance of 34%.

CONCLUSION

Birth delivery route by C-section is associated with lowered (or flattened) cortisol levels in children born prematurely. This is clinically relevant and might have important implications, because an HPA-axis disturbance might lead to developmental problems later on in life. However, future research is necessary to investigate the underlying indications for performing a C-section, which will help to understand factors that influence the HPA-axis development in children born prematurely.

Salivary Diurnal Glucocorticoid Profiles in Monozygotic Twins With Intratwin Birthweight Differences

CONTEXT

Low birthweight (bw) and unfavorable intrauterine conditions have been associated with metabolic sequelae in later life, but little is known about their impact on glucocorticoid metabolism.

OBJECTIVE

We studied monozygotic twins with intratwin bw differences to analyze the long-term impact of bw on glucocorticoid metabolism.

METHODS

46 monozygotic twin pairs with bw differences of <1 SDS (concordant; n = 29) and ≥1 SDS (discordant; n = 17) were recruited. At 6.9 years (mean age), saliva samples were collected (at 7 hours, 13 hours, 18 hours and 21 hour) and analyzed with liquid chromatography-tandem mass spectrometry (LC-MS/MS).

RESULTS

We found significant or highly significant intratwin correlations in all twin pairs at 3 of 4 (cortisol), and 4 of 4 (cortisone) time points. Graphic evaluation of the diurnal cortisol patterns for each twin pair showed a distinct alignment in all groups. Analyses of the change of intratwin differences over the day by mixed linear modeling showed no intratwin differences in diurnal patterns. Regression analyses of intratwin differences at 7:00 hours showed a significant influence of catch-up growth, indicating lower cortisol concentrations in smaller twins with more catch-up growth (adj. R2 = 0.159, P = .014, ß = -3.71, F(1,42) = 9.15, f2 = 0.19).

CONCLUSION

In monozygotic twins with intratwin bw differences, intratwin catch-up growth showed a moderate influence on intratwin differences in morning cortisol concentrations. We observed no differences regarding diurnal patterns. In contrast, in all groups, we found significant intratwin correlations for cortisol and cortisone over the day and a pronounced graphic alignment of cortisol diurnal patterns. We therefore suggest a predominant significance of the genetic background compared with bw differences on cortisol metabolism.

Extremely and very preterm children who were born appropriate for gestational age show no differences in cortisol concentrations or diurnal rhythms compared to full-term children

OBJECTIVES

The objective of this study was to compare the diurnal variations in cortisol and cortisone concentrations in serum and saliva among extremely preterm (EPT), very preterm (VPT), and full-term (FT) children, all born appropriate for gestational age (AGA).

METHODS

EPT, VPT, and FT children, all born AGA, were recruited from two healthcare centers. Cortisol and cortisone concentrations in serum and saliva were measured by liquid chromatography-mass spectrometry (LC‒MS). Statistical analysis was performed using nonparametric tests.

RESULTS

A total of 101 children (5.0-8.9 years old) were included in this study: EPT=18, VPT=43 and FT=40. All groups had similar distributions in terms of age, birth weight standard deviation score (SDS) and BMI (SDS), showing no differences in serum ACTH, cortisol, or cortisone levels. Additionally, salivary cortisol and cortisone concentrations decreased significantly throughout the day (p-values<0.0001). Salivary cortisol concentrations were below the limit of detection (0.55 nmol/L) before dinner and before bedtime in approximately one-third and two-thirds of all children, respectively. Salivary cortisone was detectable in all but one sample.

CONCLUSIONS

The diurnal cortisol rhythm was preserved in all preterm children, regardless of their gestational age, and no differences in cortisol concentrations among the groups were found. This may have significant implications for the clinical management and follow-up of preterm individuals.

Saliva cortisol diurnal variation and stress responses in term and preterm infants

OBJECTIVE

To determine if preterm birth is associated with adaptation of the hypothalamic-pituitary-adrenal (HPA) axis and whether HPA axis programming relates to the degree of prematurity (defined as extremely preterm birth at <28 weeks or very preterm birth at 28-32 weeks gestation).

DESIGN

This study reports findings from a prospective birth cohort. Saliva cortisol concentrations were measured prevaccination and postvaccination, and in the morning and evening, at 4 months chronological age.

SETTING

Infants born at a single Scottish hospital.

PARTICIPANTS

45 term-born, 42 very preterm and 16 extremely preterm infants.

OUTCOMES

Cortisol stress response to vaccination (postvaccination minus prevaccination cortisol concentrations), diurnal slope (log-transformed morning minus log-transformed evening cortisol values) and mean log-transformed daily cortisol.

RESULTS

Compared with infants born at term, infants born extremely preterm had a blunted cortisol response to vaccination (5.8 nmol/L vs 13.1 nmol/L, difference in means: -7.3 nmol/L, 95% CI -14.0 to -0.6) and a flattened diurnal slope (difference in geometric means: -72.9%, 95% CI -87.1 to -42.8). In contrast, the cortisol response to vaccination (difference in means -2.7 nmol/L, 95% CI -7.4 to 2.0) and diurnal slope at 4 months (difference in geometric means: -33.6%, 95% CI -62.0 to 16.0) did not differ significantly in infants born very preterm compared with infants born at term.

CONCLUSIONS

Infants born extremely preterm have blunted cortisol reactivity and a flattened diurnal slope. These patterns of HPA axis regulation are commonly seen after childhood adversity and could contribute to later metabolic and neurodevelopmental phenotypes observed in this population.

Mother's Own Milk Compared With Formula Milk for Feeding Preterm or Low Birth Weight Infants: Systematic Review and Meta-analysis

OBJECTIVES

We assessed the effect of feeding preterm or low birth weight infants with infant formula compared with mother's own milk on mortality, morbidity, growth, neurodevelopment, and disability.

METHODS

We searched Medline (Ovid), Embase (Ovid), and Cochrane Central Register of Controlled Studies to October 1, 2021.

RESULTS

Forty-two studies enrolling 89 638 infants fulfilled the inclusion criteria. We did not find evidence of an effect on mortality (odds ratio [OR] 1.26, 95% confidence interval [CI] 0.91-1.76), infection (OR 1.52, 95% CI 0.98-2.37), cognitive neurodevelopment (standardized mean difference -1.30, 95% CI -3.53 to 0.93), or on growth parameters. Formula milk feeding increased the risk of necrotizing enterocolitis (OR 2.99, 95% CI 1.75-5.11). The Grading of Recommendations Assessment, Development, and Evaluation certainty of evidence was low for mortality and necrotizing enterocolitis, and very low for neurodevelopment and growth outcomes.

CONCLUSIONS

In preterm and low birth weight infants, low to very low-certainty evidence indicates that feeding with infant formula compared with mother's own milk has little effect on all-cause mortality, infection, growth, or neurodevelopment, and a higher risk of developing necrotizing enterocolitis.

Redox ratio in the left ventricle of the growth restricted fetus is positively correlated with cardiac output

Intrauterine growth restriction (IUGR) is a result of limited substrate supply to the developing fetus in utero, and can be caused by either placental, genetic or environmental factors. Babies born IUGR can have poor long-term health outcomes, including being at higher risk of developing cardiovascular disease. Limited substrate supply in the IUGR fetus not only changes the structure of the heart but may also affect metabolism and function of the developing heart. We have utilised two imaging modalities, two-photon microscopy and phase-contrast MRI (PC-MRI), to assess alterations in cardiac metabolism and function using a sheep model of IUGR. Two-photon imaging revealed that the left ventricle of IUGR fetuses (at 140-141 d GA) had a reduced optical redox ratio, suggesting a reliance on glycolysis for ATP production. Concurrently, the use of PC-MRI to measure foetal left ventricular cardiac output (LVCO) revealed a positive correlation between LVCO and redox ratio in IUGR, but not control fetuses. These data suggest that altered heart metabolism in IUGR fetuses is indicative of reduced cardiac output, which may contribute to poor cardiac outcomes in adulthood.

Maternally derived low glucocorticoid mediates adrenal developmental programming alteration in offspring induced by dexamethasone

Adverse environments during pregnancy can increase susceptibility to chronic diseases in adult offspring. The occurrence and development of fetal-originated diseases were associated with adrenal developmental programming and homeostasis alteration in offspring. Dexamethasone is widely used for preterm delivery-related pregnancy diseases, but the intrauterine programming alteration and its occurrence mechanism of prenatal dexamethasone exposure (PDE) on adrenal development in offspring have not been clarified. In this study, prenatal dexamethasone therapy could inhibit neonatal development and cause a low exposure of maternally derived glucocorticoid in clinic. Then, we established a rat model of PDE and observed a similar phenomenon. Further, the adrenal steroidogenic function was continuously inhibited in the PDE male offspring rats, accompanied by the decreased H3K27ac level of adrenal insulin-like growth factor 1 (IGF1) and its expression. Moreover, chronic stress in PDE adult offspring rats could reverse the changes of the above indicators through the high level of glucocorticoid. In combination with in vivo, in vitro and a series of interference experiments, we confirmed that the low level of endogenous glucocorticoids inhibited the adrenal IGF1 expression and steroidogenic function through the GRα/miR-370-3p/Sirt3 pathway. In summary, PDE could continuously inhibit the adrenal steroidogenic function in the male offspring, which is associated with the maternally derived low glucocorticoid-mediated the adrenal developmental programming alteration in offspring. This study provides a theoretical and experimental basis for explaining the adrenal development origin of PDE-induced adult chronic diseases.

Influence of Prenatal Environment on Androgen Steroid Metabolism In Monozygotic Twins With Birthweight Differences

OBJECTIVE

Although low birthweight (bw) and unfavorable intrauterine conditions have been associated with metabolic sequelae in later life, little is known about their impact on steroid metabolism. We studied genetically identical twins with intra-twin bw-differences from birth to adolescence to analyze the long-term impact of bw on steroid metabolism.

METHODS

68 monozygotic twin pairs with a bw-difference of <1 standard deviation score (SDS; concordant; n = 41) and ≥1 SDS (discordant; n = 27) were recruited. At 14.9 years (mean age), morning urine samples were collected and analyzed with gas chromatography-mass-spectrometry.

RESULTS

No significant differences were detected in the concordant group. In contrast, in the smaller twins of the discordant group, we found significantly higher concentrations not only of the dehydroepiandrosterone sulfate (DHEAS) metabolite 16α-OH-DHEA (P = 0.001, 656.11 vs 465.82 µg/g creatinine) but also of cumulative dehydroepiandrosterone and downstream metabolites (P = 0.001, 1650.22 vs 1131.92 µg/g creatinine). Relative adrenal (P = 0.002, 0.25 vs 0.18) and overall androgen production (P = 0.001, 0.79 vs 0.65) were significantly higher in the formerly smaller discordant twins. All twin pairs exhibited significant intra-twin correlations for all individual steroid metabolites, sums of metabolites, indicators of androgen production, and enzyme activities. Multiple regression analyses of the smaller twins showed that individual steroid concentrations of the larger co-twin were the strongest influencing factor among nearly all parameters analyzed.

CONCLUSION

In monozygotic twin pairs with greater intra-twin bw-differences (≥1 SDS), we found that bw had a long-lasting impact on steroid metabolism, with significant differences regarding DHEAS metabolites and relative androgen production. However, most parameters showed significant intra-twin correlations, suggesting a consistent interrelationship between prenatal environment, genetic background, and steroid metabolism.

The IGF system and longitudinal growth in preterm infants in relation to gestational age, birth weight and gender

OBJECTIVE

Growth factors in the blood of very preterm infants may reflect growth and contribute to the understanding of early development. We investigated postnatal levels of insulin-like growth factors (IGFs) in infants born very preterm and related them to early growth development.

DESIGN

Blood samples were analyzed weekly for IGF-I, IGF-II, IGF binding protein (BP)-1, IGFBP-3, and acid-label subunit (ALS).

METHODS

73 children born very preterm (gestational age (GA) <32 weeks) were divided according to their gender-specific birth weight standard deviation score (SDS) into either appropriate for GA (AGA) or small for GA (SGA). Fifty-two (71%) and forty-three (59%) infants completed follow-up with anthropometry at approximately 3 years and at 5 years of age respectively. Thirty-six subjects (49%) had blood sampling for IGF-I and IGFBP-3 measurements up to 3 years of age.

RESULTS

IGF-I, IGFBP-3, and ALS levels increased in all groups from week 31 to week 36, with generally lower levels in the SGAs, with a concomitant lower growth velocity. Postnatal ALS was strongly associated with IGF-I and IGFBP-3 in boys, girls and AGA infants. IGF-II was higher in earlier born preterms (GA < 27 weeks) at postmenstrual ages 27.5-29.9 weeks compared with SGAs and late GA (GA ≥ 27 weeks) preterms (p < .0001). IGF-II, in contrast to IGF-I, did not differ between SGAs and AGAs at weeks 31-36. Mean IGFBP-1 was highest in the SGAs compared to AGAs at mean week 28,5 and 31 (p = .001) and IGFBP-1 levels were elevated in relation to IGF-I in the SGAs at that period. At follow-up, the increase in IGF-I between week 31 and 33.5 was a significant positive determinant of height SDS at 3 and 5 years of age in forward multiple regression analysis, independent of target height.

CONCLUSION

This is the first study to investigate postnatal ALS levels in preterm infants. In very preterm infants, IGF-II is less affected by size at birth during early postnatal weeks compared with IGF-I. Early elevated IGFBP-1 might protect the SGA infants from an intense metabolic rate. Our results indicate that anabolic and metabolic processes during weeks 31-36 predicts later height.

Prenatal and childhood predictors of hair cortisol concentration in mid-childhood and early adolescence

Background

Hair cortisol concentration (HCC) is an increasingly used measure of systemic cortisol concentration. However, determinants of HCC in children and adolescents are unclear because few prospective studies have been conducted to date.

Study design

We followed 725 children in Project Viva, a pre-birth cohort study of mothers and children, who provided hair samples at mid-childhood (median age: 7.7 years) or early adolescence (median age: 12.9 years). We examined associations of various factors measured from pregnancy to mid-childhood with HCC in mid-childhood and early adolescence, as well as change in HCC between these time points (ΔHCC).

Results

There were 426 children with HCC measurements in both mid-childhood and early adolescence, 173 children with measures only in mid-childhood, and 126 with measures only in early adolescence. HCC was lower in mid-childhood (median 1.0pg/mg [interquartile range, IQR: 0.5, 2.4]) than early adolescence (2.2pg/mg [1.1, 4.4]). In multivariable-adjusted regression models, female sex (β = -0.41, 95% CI: -0.67, -0.15) and birth weight-for-gestational age z-score (β = -0.19, 95% CI: -0.33, -0.04) were associated with lower mid-childhood HCC, while prenatal smoking was associated with higher mid-childhood HCC (β = 0.53, 95% CI: 0.04, 1.01). In early adolescence, child age (β = 0.34 per year, 95% CI: 0.21, 0.46) female sex (β = 0.33, 95% CI: 0.10, 0.57), and maternal pre-pregnancy body mass index (β = 0.15 per 5-kg/m², 95% CI: 0.01, 0.29) were positively associated with HCC. Child anthropometric measures and biomarker concentrations were not associated with HCC.

Conclusion

Maternal pre-pregnancy BMI, maternal prenatal smoking, and low birth weight were associated with higher mid-childhood and adolescent HCC. However, few postnatal characteristics were associated with HCC.

Physical Activity and Spatial Memory Are Minimally Affected by Moderate Growth Restriction in Preterm Piglets

BACKGROUND

Preterm birth is associated with impaired brain functions, but it is unknown whether fetal growth restriction (GR) makes these deficits worse. Using piglets as a model for preterm infants, we hypothesized that moderate GR reduces growth rate, physical activity, and spatial memory in the first weeks after preterm birth.

METHODS

Preterm pigs were delivered by caesarean section and fed until 19 days (n = 830 from 55 pregnant sows) and received intensive clinical care. GR pigs were classified as animals with the lowest 5-20% percentile birth weight within each litter and were compared with litter-mate controls (21-100% percentile birth weight). Basic motor skill development, physical activity, and morbidities (e.g., necrotizing enterocolitis) were recorded within the first week. Weight of internal organs and data from a T-maze spatial memory test were noted until 19 days.

RESULTS

Moderate GR and control preterm pigs (birth weights 728 ± 140 and 1,019 ± 204 g, respectively) showed similar relative weights of internal organs (relative to body), except higher adrenal gland weights in GR pigs (+20-50%, p < 0.05). This was associated with a tendency to higher plasma cortisol (p < 0.05 on day 11). GR preterm pigs showed delayed ability to stand and walk (days 2-5, p < 0.01), but physical activity and proportion of correct choices in a T-maze test (70.3 vs. 71.6%) were similar.

CONCLUSION

Moderate GR has limited effect on motor function and spatial memory in the early postnatal period of preterm pigs, despite some initial delays in basic motor skills. In the postnatal period, moderately growth-restricted preterm infants may adapt well with regards to organ growth and neurodevelopment.

Adrenal Function in Adolescence is Related to Intrauterine and Postnatal Growth

Background and objectives: Intrauterine growth restriction is thought to be implicated in long-term programming of hypothalamic-pituitary-adrenal axis activity. We investigated adrenal function in adolescents born small for gestational age (SGA) in relation to their postnatal growth and cardiovascular parameters. Materials and Methods: Anthropometric parameters, blood pressure, heart rate, dehydroepiandrosterone sulfate (DHEAS), and cortisol levels were assessed in 102 adolescents aged 11-14 years followed from birth (47 SGA and 55 born appropriate for gestational age (AGA)). Results: Mean DHEAS levels were higher in SGA adolescents with catch-up growth (SGACU+), compared with AGA. Second-year height velocity and body mass index (BMI) gain during preschool years were positively related to DHEAS levels. Morning cortisol levels and systolic and diastolic blood pressure were higher in SGA adolescents without catch-up growth (SGACU-) compared with AGA. Second-year BMI gain was inversely, and 2-12 years increase in subscapular skinfold thickness was directly associated with cortisol levels. Size at birth and postnatal growth explained 47.8% and 38.2% of variation in DHEAS and cortisol levels, respectively. Conclusion: Adrenal function in adolescence is affected by prenatal and postnatal growth: small size at birth with postnatal catch-up growth is related to higher DHEAS secretion, whereas increased cortisol levels and blood pressure are higher in short SGA adolescents.

Intrauterine growth and the maturation process of adrenal function

BACKGROUNDS

Environmental factors during early life alter the hypothalamus-pituitary-adrenal (HPA) axis regulation and increase the risk of diseases in later life. However, adrenal function at each developmental stage has not fully been investigated in relation to pathological antenatal conditions. Cortisol levels of newborns with intrauterine growth restriction (IUGR) are elevated during the neonatal period; however, when studied during early childhood, cortisol levels are reduced compared with their peers, suggesting that the HPA axis regulation might be altered from activation to suppression, the timing of which remains uncertain.

AIM

The aim of this study was to assess the presence of an interaction between intrauterine growth and postnatal age on cortisol levels in newborns hospitalised at a neonatal intensive care unit.

METHODS

We performed a secondary analysis using a dataset from saliva samples of 62 newborns collected between 30 and 40 weeks corrected age. Interactions between postnatal age and clinical variables with regard to cortisol levels were assessed.

RESULTS

The z-score of the birth weight and IUGR showed significant interactions with postnatal age on cortisol levels; cortisol levels were higher ≤5 days of birth and lower >14 days of birth than those in their peers without IUGR.

CONCLUSION

The adrenal function of newborns with IUGR might be altered from activation to suppression within the first several weeks of life. Longitudinal studies need to address when/how IUGR alters adrenal functions, and how these responses are associated with diseases during adulthood.

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 β -6.5, 95% confidence interval (CI) -9.8; -3.2, P < 0.001; neuromotor score β -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.