Preterm Birth and Corticotrophin-Releasing Hormone as a Placental Clock

Allostatic Load as a Mediator and Perceived Chronic Stress as a Moderator in the Association between Maternal Mental Health and Preterm Birth: A Prospective Cohort Study of Pregnant Women in Pakistan

INTRODUCTION

The complex biopsychosocial pathways linking maternal mental health with preterm birth (PTB) are not well understood. This study aimed to explore allostatic load (AL) as a mediator and perceived chronic stress as a moderator in the pathway linking maternal mental health and PTB.

METHODS

A cohort study of pregnant women (n = 1,567) recruited at clinic visits within 10-19 weeks of gestation was assessed for maternal mental health (i.e., pregnancy-related anxiety, state anxiety, depressive symptoms) and perceived chronic stress. Blood pressure and levels of cortisol, total cholesterol, C-reactive protein, and glycosylated hemoglobin were used to create a composite measure of AL.

RESULTS

AL had the most significant effect on PTB (odds ratio (OR) = 1.84, 95% CI = 1.26-12.67, p = 0.001), while systolic blood pressure emerged as the only significant individual marker using variable selection (OR = 22%, 95% CI = 1.06-1.40, p < 0.001) in multiple logistic regression analysis. A mediation analysis revealed that maternal mental health did not have a significant direct effect on PTB (p = 0.824), but its indirect effect mediated by AL was significant (z = 2.33, p < 0.020). Low and high levels of perceived chronic stress, relative to the mean, moderated this indirect effect (z = 3.66, p < 0.001).

CONCLUSIONS

AL has a significant direct influence on PTB and mediates the effect of maternal mental health on PTB; however, the indirect effect of AL is indistinguishable between women with higher or lower levels of perceived chronic stress than normal.

Through a teratological lens: A narrative review of exposure to stress and drugs of abuse during pregnancy on neurodevelopment

Teratological research shows that both prenatal stress and prenatal substance exposure have a significant impact on neurodevelopmental outcomes in children. Using human research, the purpose of this narrative review is to explore the degree to which these exposures may represent complex prenatal and postnatal risks for the development of cognition and behavior in children. An understanding of the HPA axis and its function during pregnancy as well as the types and operationalization of prenatal stress provide a context for understanding the direct and indirect mechanisms by which prenatal stress affects brain and behavior development. In turn, prenatal substance exposure studies are evaluated for their importance in understanding variables that indicate a potential interaction with prenatal stress including reactivity to novelty, arousal, and stress reactivity during early childhood. The similarities and differences between prenatal stress exposure and prenatal substance exposure on neurodevelopmental outcomes including arousal and emotion regulation, cognition, behavior, stress reactivity, and risk for psychopathology are summarized. Further considerations for teratological studies of prenatal stress and/or substance exposure include identifying and addressing methodological challenges, embracing the complexity of pre-and postnatal environments in the research, and the importance of incorporating parenting and resilience into future studies.

Women's experiences with continuity for effective coordination during maternal and neonatal continuum in Kenya: An interpretive phenomenology

BACKGROUND

 Embracing women's experiences in decision-making is imperative for continuity in effective coordination of maternal and neonatal health (MNH); women are the end users within the care ecosystem. Through women's continuous feedback, skilled birth attendants (SBAs) and the healthcare system get to understand emerging issues based on their needs and preferences.

AIM

 The purpose of this article is to describe women's experiences of continuity for effective coordination of care through the transitions in the MNH continuum in Kenya.

SETTING

 The study was conducted in selected counties of Kenya based on birth rates per woman as follows: Wajir (7.8) Narok (6.0) Kirinyaga (2.3) and Nairobi (2.7) (1). The clients were interviewed concerning their experiences of the MNH continuum of care in English and Kiswahili.

METHODS

 An interpretive hermeneutic phenomenological approach was used to construct the experiences of women of continuity during transitions in the MNH continuum for effective care coordination. Twelve participants were interviewed between January and April 2023. Atlas ti 22 software was used for data analysis.

RESULTS

 Four women experiences were highlighted: Women unawareness of preconception care, use of prenatal care, labour, birthing and postpartum flow and the women's view on the MNH continuum.

CONCLUSION

 The women reported their segmental and transitional experience of the MNH continuum as one that did not consistently meet their needs and preferences in order for them to fully agree that the continuum enhanced continuity for effective coordination. They felt that they experienced continuity in some segments while in some they did not.Contribution: The embrace of women's experience of their needs and preferences through the MNH continuum (segments and transitional segments) through the lens of continuity for effective coordination is timely towards the improvement of maternal and neonatal care by 2030.

Optimizing Newborn Outcomes in Cesarean Sections: A Comparative Analysis of Stress Indicators under General and Spinal Anesthesia

BACKGROUND AND OBJECTIVES

The moment of birth represents a complex physiological process that is followed by adaptive changes in the vital systems of the newborn. Such reactions have their positive but also negative effects. The aim of this research was to determine the difference in laboratory values of stress indicators in newborn children delivered by cesarean section (CS) with general and spinal anesthesia. We attempted to make a recommendation about the optimal type of anesthesia based on our results.

MATERIALS AND METHODS

The study was performed on 150 healthy term newborns delivered by urgent or planned CS. Samples for adrenocorticotropic hormone (ACTH), cortisol, triglycerides, and interleukin-6 (IL-6) were analyzed.

RESULTS

Leukocyte numbers, triglycerides, and blood sugar values were normal for the newborns' age, with statistically significantly lower values of blood sugar and triglycerides in newborns delivered by CS in spinal anesthesia (p < 0.005) compared to general anesthesia. There were no significant differences in ACTH, cortisol, and IL-6 levels between those newborns delivered via CS after spinal or general anesthesia.

CONCLUSIONS

In cases where vaginal delivery is not possible, when CS is indicated, the use of well-controlled spinal anesthesia is followed by lower degrees of metabolic, inflammatory, and stress responses and better vitality of the baby upon birth.

Sex-specific associations between placental corticotropin releasing hormone and problem behaviors in childhood

Placental corticotropin-releasing hormone (pCRH) is a neuroactive peptide produced in high concentrations in mid-late pregnancy, during key periods of fetal brain development. Some evidence suggests that higher pCRH exposure during gestation is associated with adverse neurodevelopment, particularly in female offspring. In 858 mother-child dyads from the sociodemographically diverse CANDLE cohort (Memphis, TN), we examined: (1) the slope of pCRH rise in mid-late pregnancy and (2) estimated pCRH at delivery as a measure of cumulative prenatal exposure. When children were 4 years-old, mothers reported on problem behaviors using the Child Behavior Checklist (CBCL) and cognitive performance was assessed by trained psychologists using the Stanford-Binet Intelligence Scales. We fitted linear regression models examining pCRH in relation to behavioral and cognitive performance measures, adjusting for covariates. Using interaction models, we evaluated whether associations differed by fetal sex, breastfeeding, and postnatal neighborhood opportunity. In the full cohort, log-transformed pCRH measures were not associated with outcomes; however, we observed sex differences in some models (interaction p-values≤0.01). In male offspring, an interquartile (IQR) increase in pCRH slope (but not estimated pCRH at delivery), was positively associated with raw Total (β=3.06, 95%CI: 0.40, 5.72), Internalizing (β=0.89, 95%CI: 0.03, 1.76), and Externalizing (β=1.25, 95%CI: 0.27, 2.22) Problem scores, whereas, in females, all associations were negative (Total Problems: β=-1.99, 95%CI: -3.89, -0.09; Internalizing: β=-0.82, 95%CI: -1.42, -0.23; Externalizing: β=-0.56, 95%CI: -1.34, 0.22). No associations with cognitive performance were observed nor did we observe moderation by breastfeeding or postnatal neighborhood opportunity. Our results provide further evidence that prenatal pCRH exposure may impact subsequent child behavior in sex-specific ways, however in contrast to prior studies suggesting adverse impacts in females, steeper mid-gestation pCRH rise was associated with more problem behaviors in males, but fewer in females.

Ambient temperature and preterm birth: A case-crossover study

OBJECTIVE

To investigate the association between ambient temperature and preterm birth (PTB) and to estimate the population attributable fraction (PAF) of PTBs due to low and high temperatures.

DESIGN

Time-stratified case-crossover design.

SETTING

Japan (46 prefectures, excluding Okinawa), 2011-2020.

SAMPLE

214 050 PTBs registered in the Japan Perinatal Registry Network database among 1 908 168 singleton live births.

METHODS

A quasi-Poisson regression model with a distributed lag nonlinear model was employed to assess the associations between daily mean temperature and PTBs for a lag of 0-27 days in each prefecture. A random effects meta-analysis was conducted by combining effect estimates from the 46 prefectures to estimate pooled relative risks (RRs). The PAFs of the PTBs due to below or above the mean of the 46 median temperatures (16.0°C) were calculated.

MAIN OUTCOME MEASURES

Preterm singleton live births.

RESULTS

The association between daily mean temperature and PTB risk exhibited a U-shaped curve. The adjusted RRs were 1.15 (95% confidence interval [CI] 1.05-1.25) at the mean of the 1st percentiles (0.8°C) and 1.08 (95% CI 1.00-1.17) at the mean of the 99th percentiles (30.2°C) of 46 prefectures, with 16.0°C as the reference temperature. Approximately 2.3% (95% CI 0.6-4.0) of PTBs were attributable to low temperatures.

CONCLUSIONS

Both low and possibly high temperatures were associated with an increased risk of PTBs. These findings may help to inform preventive measures for pregnant women.

Human placenta releases extracellular vesicles carrying corticotrophin releasing hormone mRNA into the maternal blood

The human placenta releases diverse extracellular vesicles (EVs), including microvesicles (100-1000 nm) and exosomes (30-150 nm), into the maternal blood for feto-maternal communication. Exosomes and microvesicles contribute to normal pregnancy physiology and major pregnancy pathologies. Differences in miRNA expressions and protein content in placental exosomes have been reported in complicated pregnancies. During human pregnancy, Corticotropin-Releasing Hormone (CRH) is produced and released by the placenta into the maternal blood. CRH is involved in regulating gestational length and the initiation of labour. CRH mRNA levels in the maternal plasma rise with gestation. High levels of CRH mRNA are reported to be associated with preeclamptic and preterm pregnancies. However, the underlying mechanism of placental CRH mRNA secretion remains to be elucidated. We hypothesise that the placenta releases CRH mRNA packaged within extracellular vesicles (EVs) into the maternal blood. In this study, placental EVs (microvesicles and exosomes) were isolated from human term healthy placentas via villus washes and from explant culture media by differential centrifugation and purified by density gradient ultracentrifugation using a continuous sucrose gradient (0.25-2.5 M). Western blotting using placenta- and exosome-specific markers and electron microscopy confirmed exosomes and microvesicles in the placental wash and explant media samples. Real-time quantitative RT-PCR data detected CRH mRNA in placenta-derived EVs from placental washes and explants. We also sorted placenta-secreted EVs in maternal plasma samples (≥37 weeks) by high-resolution flow cytometry using a fluorescent-labelled PLAP antibody. CRH mRNA was demonstrated in placental EVs obtained from maternal blood plasma. We therefore show that human placental EVs carry CRH mRNA into the maternal blood. Our study implies that measuring CRH mRNA in placental EVs in the maternal plasma could beused for monitoring pregnancy.

Unveiling the hidden players: The crucial role of transposable elements in the placenta and their potential contribution to pre-eclampsia

The human placenta is a vital connection between maternal and fetal tissues, allowing for the exchange of molecules and modulation of immune interactions during pregnancy. Interestingly, some of the placenta's unique functions can be attributed to transposable elements (TEs), which are DNA sequences that have mobilised into the genome. Co-option throughout mammalian evolution has led to the generation of TE-derived regulators and TE-derived genes, some of which are expressed in the placenta but silenced in somatic tissues. TE genes encompass both TE-derived genes with a repeat element in the coding region and TE-derived regulatory regions such as alternative promoters and enhancers. Placental-specific TE genes are known to contribute to the placenta's unique functions, and interestingly, they are also expressed in some cancers and share similar functions. There is evidence to support that aberrant activity of TE genes may contribute to placental pathologies, cancer and autoimmunity. In this review, we highlight the crucial roles of TE genes in placental function, and how their dysregulation may lead to pre-eclampsia, a common and dangerous placental condition. We provide a summary of the functional TE genes in the placenta to offer insight into their significance in normal and abnormal human development. Ultimately, this review highlights an opportunity for future research to investigate the potential dysregulation of TE genes in the development of placental pathologies such as pre-eclampsia. Further understanding of TE genes and their role in the placenta could lead to significant improvements in maternal and fetal health.

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.