Associations Between Placental Corticotropin-Releasing Hormone, Maternal Cortisol, and Birth Outcomes, Based on Placental Histopathology

The Impact of Stress, Microbial Dysbiosis, and Inflammation on Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is the leading cause of intestinal morbidity and mortality in neonates. A large body of work exists; however, the pathogenesis of NEC remains poorly understood. Numerous predictors have been implicated in the development of NEC, with relatively less emphasis on maternal factors. Utilizing human tissue plays a crucial role in enhancing our comprehension of the underlying mechanisms accountable for this devastating disease. In this review, we will discuss how maternal stress affects the pathogenesis of NEC and how changes in the intestinal microbiome can influence the development of NEC. We will also discuss the results of transcriptomics-based studies and analyze the gene expression changes in NEC tissues and other molecular targets associated with the pathogenesis of NEC.

Maternal exposure to childhood maltreatment and adverse birth outcomes

Exposure to traumatic events during pregnancy may influence pregnancy and birth outcomes. Growing evidence suggests that exposure to traumatic events well before pregnancy, such as childhood maltreatment (CM), also may influence the course of pregnancy and risk of adverse birth outcomes. We aimed to estimate associations between maternal CM exposure and small-for-gestational-age birth (SGA) and preterm birth (PTB) in a diverse US sample, and to examine whether common CM-associated health and behavioral sequelae either moderate or mediate these associations. The Measurement of Maternal Stress (MOMS) Study was a prospective cohort study that enrolled 744 healthy English-speaking participants ≥ 18 years with a singleton pregnancy, who were < 21 weeks at enrollment, between 2013 and 2015. CM was measured via the Childhood Trauma Questionnaire (CTQ) and participants above the moderate/severe cut-off for any of the five childhood abuse and neglect scales were assigned to the CM-exposed group. Common CM-associated health (obesity, depressive symptoms, hypertensive disorders) and behavioral (substance use) sequelae were obtained from standardized questionnaires and medical records. The main outcomes included PTB (gestational age < 37 weeks at birth) and SGA (birthweight < 10%ile for gestational age) abstracted from the medical record. Multivariable logisitic regression was used to test associations between CM, sequeale, and birth outcomes, and both moderation and mediation by CM-related sequelae were tested. Data were available for 657/744 participants. Any CM exposure was reported by 32% of participants. Risk for SGA birth was 61% higher among those in the CM group compared to the non-CM group (14.1% vs. 7.6%), and each subsequent form of CM that an individual was exposed to corresponded with a 27% increased risk for SGA (aOR 1.27, 95% CI 1.05, 1.53). There was no significant association between CM and PTB (9.3% vs. 13.0%, aOR 1.07, 95% CI 0.58, 1.97). Of these sequelae only hypertensive disorders were associated with both CM and SGA and hypertensive disorders of pregnancy did not mediate the association between CM and SGA. Our findings indicate that maternal CM exposure is associated with increased risk for SGA birth and highlight the importance of investigating the mechanisms whereby childhood adversity sets the trajectory for long-term and intergenerational health issues.

Postnatal corticosteroid response in neonates < 32 weeks and relation with placental pathology

Acute chorioamnionitis and maternal vascular malperfusion are associated with an increased risk of bronchopulmonary dysplasia. To prevent bronchopulmonary dysplasia, postnatal corticosteroids are given to preterm neonates. Clinical observations indicate not all neonates respond to corticosteroids, the so-called non-responders. This study aimed to investigate the association between placental pathology and short-term response to postnatal corticosteroids in neonates < 32 weeks postconceptional age at risk for bronchopulmonary dysplasia. All neonates < 32 weeks born between 2009 and 2016, receiving corticosteroids in the course of BPD, were included. The preterm neonates were divided into three groups depending on placental histology: acute chorioamnionitis, maternal vascular malperfusion, or no placental pathology. Respiratory support was assessed prior to treatment and at days 4 and 7. A responder was defined as extubation within 7 days after starting corticosteroid treatment. In total, 52% of the chorioamnionitis neonates, 67% of the maternal vascular malperfusion neonates, and 58% of neonates in the no pathology group were responders. The odds ratio for extubation was 0.53 (0.18-1.55) at day 4 and 0.66 (0.23-1.97) at day 7, in the chorioamnionitis group compared to the maternal vascular malperfusion.

CONCLUSION

Short-term response to postnatal corticosteroids did not significantly differ between premature neonates born after acute chorioamnionitis, maternal vascular malperfusion, or no placenta pathology. However, a trend of better corticosteroid response in maternal vascular malperfusion neonates was found, potentially due to differences in prenatal pulmonary development and postnatal cortisol.

WHAT IS KNOWN

• Bronchopulmonary dysplasia is related to chorioamnionitis and maternal vascular malperfusion. • Corticosteroids remain an important treatment in the course of bronchopulmonary dysplasia despite conflicting results and non-responsiveness in some preterm neonates.

WHAT IS NEW

• Non-responsiveness might be related to differences in pulmonary inflammation and systemic cortisol due to predispositions triggered by chorioamnionitis or maternal vascular malperfusion. • Neonates born after maternal vascular malperfusion seem to respond better to postnatal corticosteroid treatment.

Metabolomic profiling of intrauterine growth-restricted preterm infants: a matched case-control study

BACKGROUND

The biochemical variations occurring in intrauterine growth restriction (IUGR), when a fetus is unable to achieve its genetically determined potential, are not fully understood. The aim of this study is to compare the urinary metabolomic profile between IUGR and non-IUGR very preterm infants to investigate the biochemical adaptations of neonates affected by early-onset-restricted intrauterine growth.

METHODS

Neonates born <32 weeks of gestation admitted to neonatal intensive care unit (NICU) were enrolled in this prospective matched case-control study. IUGR was diagnosed by an obstetric ultra-sonographer and all relevant clinical data during NICU stay were captured. For each subject, a urine sample was collected within 48 h of life and underwent untargeted metabolomic analysis using mass spectrometry ultra-performance liquid chromatography. Data were analyzed using multivariate and univariate statistical analyses.

RESULTS

Among 83 enrolled infants, 15 IUGR neonates were matched with 19 non-IUGR controls. Untargeted metabolomic revealed evident clustering of IUGR neonates versus controls showing derangements of pathways related to tryptophan and histidine metabolism and aminoacyl-tRNA and steroid hormones biosynthesis.

CONCLUSIONS

Neonates with IUGR showed a distinctive urinary metabolic profile at birth. Although results are preliminary, metabolomics is proving to be a promising tool to explore biochemical pathways involved in this disease.

IMPACT

Very preterm infants with intrauterine growth restriction (IUGR) have a distinctive urinary metabolic profile at birth. Metabolism of glucocorticoids, sexual hormones biosynthesis, tryptophan-kynurenine, and methionine-cysteine pathways seem to operate differently in this sub-group of neonates. This is the first metabolomic study investigating adaptations exclusively in extremely and very preterm infants affected by early-onset IUGR. New knowledge on metabolic derangements in IUGR may pave the ways to further, more tailored research from a perspective of personalized medicine.

The influence of maternal anxiety and cortisol during pregnancy on childhood anxiety symptoms

BACKGROUND

The etiology of child and adolescent anxiety remains poorly understood. Although several previous studies have examined associations between prenatal maternal psychological functioning and infant and child health outcomes, less is known about the impact of maternal anxiety specific to pregnancy and cortisol during pregnancy on childhood anxiety outcomes.

METHODS

Participants included 496 mother-child pairs from the PROGRESS longitudinal birth cohort in Mexico City. Anxiety symptoms were assessed at age 8-11 years during 2018-2019 using the Revised Children's Manifest Anxiety Scale. Pregnancy-specific anxiety was assessed using an expanded version of the Pregnancy Anxiety Scale. Maternal biological stress response during pregnancy was assessed using salivary cortisol measures (area under the curve, cortisol awakening response, and diurnal slope). Linear regression models were used to estimate associations between maternal anxiety and cortisol in relation to continuous child anxiety symptom T-scores. Models were adjusted for maternal age, socioeconomic status, child sex and age, and gestational age at saliva collection.

RESULTS

We found that higher levels of pregnancy-specific anxiety in the mother were associated with higher anxiety symptoms in the child (β: 1.30, 95% CI: 0.19, 2.41). We additionally observed an association between higher maternal total cortisol output during pregnancy and higher anxiety symptoms in the child (β: 1.13, 95% CI: 0.25, 2.01).

DISCUSSION

These findings highlight the importance of screening for maternal pregnancy-specific anxiety and the need to identify interventions and support for mothers during pregnancy in order to promote healthy outcomes for mothers and their children.

Molecular and endocrine mechanisms involved in preterm birth

Preterm birth is a worldwide social problem. Incidence rates may vary from 5 to 18% of all deliveries, with important differences observed between developed and developing countries. Preterm birth has a negative impact on newborns and neonatal mortality and morbidity are high. Despite improvements in modern neonatal care, we know little of the mechanisms that determine the onset and development of preterm birth. Infections seem to be one the most important triggers, determining the activation of protective mechanisms aimed at ending the pregnancy and safeguarding the health of the woman. However, threatened preterm birth often occurs even in women who do not have any ongoing infectious process. Of these, which are the majority, the causes and the activation mechanisms remain unknown or unclear; however, there are several molecular and endocrine mechanisms that finally lead to preterm birth. In this review, we seek to shed light and summarize the molecular and endocrine mechanisms underlying the development of preterm birth. Their understanding could help us to understand the dynamics of premature birth but, above all, to allow an early diagnosis and primary prevention of the problem.

Antepartum Depression and Preterm Birth: Pathophysiology, Epidemiology, and Disparities due to structural racism

PURPOSE OF REVIEW

Informed by the evidence of links between physiology of stress and parturition, we review recent epidemiologic evidence (2015-2020) of antenatal depression as a risk factor for preterm birth (PTB). We also explain racial/ethnic disparities in depression and preterm birth as a consequence of structural racism.

RECENT FINDINGS

Epidemiologic evidence is consistent in linking antepartum depression with an elevated risk of PTB. Antidepressant usage has been linked with an elevated risk of PTB. However, recent evidence suggests that severity of depression is the underlying driver of the elevated risk attributed to antidepressant usage. The number of depressive symptoms, as a proxy for severity of maternal stress, may be a more informative predictor of PTB than criterion based predictors. Across various study designs, measurement modalities, and populations, antenatal depression predicts an elevated risk of delivering preterm. The physiology of stress provides a plausible explanation for this observation. Excessive stress-induced elevations in maternal and then fetal HPA hormones can alter maternal and fetal homeostasis and hasten the timing of parturition. Antenatal depression and exposure to structural racism are two stressors that can trigger the maternal stress response. Chronically elevated levels of stress hormones among women of color in the USA provide a likely physiologic explanation for Black-White disparities in the risk of PTB. Focusing on the number of depressive symptoms as the more informative predictor of PTB raises several questions. We consider these questions as well as directions for future research in the context of recent advances in the field.