Consequences of Prematurity on Cortisol Regulation and Adjustment Difficulties: A 9-Year Longitudinal Study

The cortisol awakening response in very preterm born adults compared to term born adults

Very preterm infants are at higher risk of long-term neurodevelopmental and psychiatric impairments, including anxiety. Prematurity is also linked to altered programming of the hypothalamus-pituitary-adrenal (HPA) axis, associated with stress-related diseases. The cortisol awakening response (CAR), marked by a rapid cortisol increase after waking, is a biomarker of HPA reactivity and is linked to psychiatric disorders. This study aimed to evaluate for the first time the CAR in adults born very preterm and to explore its association with anxiety and stress. Twenty-five young adults born very preterm and 24 age- and sex-matched term-born controls collected saliva samples on two consecutive mornings at 0, 30, 45, and 60 min after awakening. Anxiety was measured using the State-Trait Anxiety Inventory, and stress was assessed with the Perceived Stress Scale. The CAR was analyzed using the sample at 0 min (S1), total cortisol output (AUCg), and actual CAR (AUCi). There were no significant differences in AUCi. The preterm group exhibited lower S1 levels and a reduced AUCg. Preterm-born participants reported higher trait anxiety and stress, though no consistent link with the CAR was identified. Findings suggest long-term neuroendocrine changes in adults born very preterm, warranting further research. Clinical Trial Registration: Duetsche Register Klinischer Studien (DRKS): 00020235.

The impact of skin-to-skin contact upon stress in preterm infants in a neonatal intensive care unit

Introduction

Neonatal stress significantly affects the early adaptation, maturation and long-term development of preterm infants.

The objective of the study

To investigate the effect of skin-to-skin contact (SSC) on stress level in preterm infants.

Materials and methods

The research was a prospective study. Stress indicators (cortisol, melatonin) were measured before the SSC began (pre-intervention level) and after this intervention (post-intervention).

Results

The study included 150 preterm infants in the NICU with gestational age (GA) ≤36 weeks. Pre-intervention salivary cortisol level was higher in extremely and very preterm neonates compared to moderate and late preterm newborns (p = 0.028), in children with low Apgar scores (p = 0.041), in those who were on mechanical ventilation (p = 0.005), and suffered neonatal sepsis (p = 0.005). Pre-intervention melatonin level was lower in children with low Apgar scores (p = 0.032). Salivary cortisol levels were significantly decreased after SSC in preterm infants [pre-intervention: 0.294 (0.111; 0.854) μg/dL vs. post-intervention: 0.127 (0.070; 0.229) μg/dL, p < 0.001], and urinary melatonin levels were significantly increased after SSC [pre-intervention: 4.01 (2.48; 6.34) ng/mL vs. post-intervention: 5.48 (3.39; 9.17) ng/mL, p < 0.001]. A greater reduction in cortisol levels after skin-to-skin contact was revealed in infants with a lower gestational age (p = 0.022), in boys compared to girls (p = 0.012), in infants with respiratory distress syndrome (p = 0.048), in those who had mechanical ventilation compared to non-ventilated neonates (p = 0.008), and in infants with seizures (p = 0.036). The melatonin levels increased more intensively in infants with low Apgar scores (p = 0.002), and in those with late-onset sepsis (p = 0.006).

Conclusion

The reduction in cortisol levels and the increase in melatonin levels provided strong evidence that SSC ameliorated the NICU-related stress in preterm infants. We found higher indicators of stress and more dramatic responses to SSC in reducing indicators of stress in infants with lower GA than in infants with higher GA, indicating that SSC may be even more important for lower GA infants. The infants who need SSC the most should not be denied the care they need to reduce the stress they experience from being born too soon and continuing their gestational development in the stressful environment of the NICU.

Salivary Cortisol Levels after Hydrotherapy and Land-Based Therapy as a Marker of Stress in Children with Psychomotor Developmental Disorders: A Pilot Study

Background: The number of children experiencing postnatal situations of neurological risk (such as psycho-motor developmental disorders and delays) after birth has increased in recent years. These infants often require multiple pediatric interventions to address functional problems that might generate stress, anxiety, and discomfort. The aim of the present study is to determine whether the level of salivary cortisol, as a stress marker, increases after hydrotherapy and land-based therapy in children at risk of or currently presenting delayed psycho-motor development. Methods: Saliva samples were collected from 25 children (aged 3-36 months) between June 2022 and January 2023 at the Rehabilitation and Physical Medicine Clinical Management Unit of the Virgen de las Nieves University Hospital, Granada, Spain. Three samples were collected from each child, representing baseline, post-hydrotherapy and post-land-based therapy. Result: All salivary cortisol levels were within the normal range. Resting values were the highest, and both modes of therapy decreased salivary cortisol levels. There were no statistically significant differences between the two therapies. Conclusions: Both therapies appear to be useful for treating children with psychomotor developmental disorders without increasing stress during physiotherapy sessions. Although cortisol levels were slightly higher with hydrotherapy than with land-based therapy, this may be due to the small sample size.

Preterm birth: A neuroinflammatory origin for metabolic diseases?

Preterm birth and its related complications have become more and more common as neonatal medicine advances. The concept of "developmental origins of health and disease" has raised awareness of adverse perinatal events in the development of diseases later in life. To explore this concept, we propose that encephalopathy of prematurity (EoP) as a potential pro-inflammatory early life event becomes a novel risk factor for metabolic diseases in children/adolescents and adulthood. Here, we review epidemiological evidence that links preterm birth to metabolic diseases and discuss possible synergic roles of preterm birth and neuroinflammation from EoP in the development of metabolic diseases. In addition, we explore theoretical underlying mechanisms regarding developmental programming of the energy control system and HPA axis.

Modulation of fetoplacental growth, development and reproductive function by endocrine disrupters

Maternal endocrine homeostasis is vital to a successful pregnancy, regulated by several hormones such as human chorionic gonadotropin, estrogen, leptin, glucocorticoid, insulin, prostaglandin, and others. Endocrine stress during pregnancy can modulate nutrient availability from mother to fetus, alter fetoplacental growth and reproductive functions. Endocrine disrupters such as bisphenols (BPs) and phthalates are exposed in our daily life's highest volume. Therefore, they are extensively scrutinized for their effects on metabolism, steroidogenesis, insulin signaling, and inflammation involving obesity, diabetes, and the reproductive system. BPs have their structural similarity to 17-β estradiol and their ability to bind as an agonist or antagonist to estrogen receptors to elicit an adverse response to the function of the endocrine and reproductive system. While adults can negate the adverse effects of these endocrine-disrupting chemicals (EDCs), fetuses do not equip themselves with enzymatic machinery to catabolize their conjugates. Therefore, EDC exposure makes the fetoplacental developmental window vulnerable to programming in utero. On the one hand prenatal BPs and phthalates exposure can impair the structure and function of the ovary and uterus, resulting in placental vascular defects, inappropriate placental expression of angiogenic growth factors due to altered hypothalamic response, expression of nutrient transporters, and epigenetic changes associated with maternal endocrine stress. On the other, their exposure during pregnancy can affect the offspring's metabolic, endocrine and reproductive functions by altering fetoplacental programming. This review highlights the latest development in maternal metabolic and endocrine modulations from exposure to estrogenic mimic chemicals on subcellular and transgenerational changes in placental development and its effects on fetal growth, size, and metabolic & reproductive functions.