Exploring the relationship of second-trimester corticotropin releasing hormone, chronic stress and preterm delivery

Associations between Phthalate Exposure and Gestational Age at Delivery in a Diverse Pregnancy Cohort

The association between prenatal phthalate exposure and late preterm birth (LPTB) is unclear. We examined singleton pregnancies (2006-2011) from a racially and socioeconomically diverse sample of women in the CANDLE cohort of the ECHO-PATHWAYS Consortium. Urine collected in the second and third trimester was analyzed for 14 phthalate metabolites. Multivariate logistic and linear regressions were performed for LPTB, defined as delivery 34-37 weeks, and gestational week, respectively. Models were controlled for socio-demographics, behavioral factors, clinical measurements, medical history, and phthalates in the other trimester. Effect modification by race and pregnancy stress, indicated by intimate partner violence (IPV), was investigated. We conducted a secondary analysis in women with spontaneous preterm labor. The rate of LPTB among 1408 women (61% Black, 32% White) was 6.7%. There was no evidence of decreased gestational age (GA) in association with any phthalate metabolite. Each two-fold increase in third trimester mono-benzyl phthalate (MBzP) was associated with 0.08 weeks longer gestational age (95% CI: 0.03, 0.12). When restricting to women with spontaneous labor, second trimester mono-n-butyl phthalate (MBP) was associated with 54% higher odds (95% CI: 2%, 132%) of LPTB. Associations were not modified by maternal race or IPV exposure. In conclusion, we observed mixed evidence concerning our hypothesis that prenatal phthalate exposure increases risk of LPTB, though secondary analyses suggest increased risk of spontaneous LPTB associated with MBP, which is consistent with a recent pooled analysis of 16 cohorts.

Maternal perceived stress and the increased risk of preterm birth in a majority non-Hispanic Black pregnancy cohort

OBJECTIVE

To determine whether perceived stress is associated with preterm birth (PTB) and to investigate racial differences in stress and PTB.

STUDY DESIGN

A secondary analysis of a prospective cohort study of 1911 women with singleton pregnancies examined responses to psychosocial stress questionnaires at 16-20 weeks of gestation.

RESULTS

High perceived stress (19%) and PTB (10.8%) were prevalent in our sample (62% non-Hispanic Black). Women with PTB were more likely to be Black, have chronic hypertension (cHTN), pregestational diabetes, and higher BMI. Women with high perceived stress had more PTBs than those with lower stress (15.2% vs. 9.8%), and stress was associated with higher odds of PTB (aOR: 1.55, 95% CI: 1.09-2.19).

CONCLUSION

The significant association between high perceived stress and PTB suggests that prenatal interventions to reduce maternal stress could improve the mental health of pregnant women and may result in reduced rates of PTB.

Nativity-Related Disparities in Preterm Birth and Cardiovascular Risk in a Multiracial U.S. Cohort

INTRODUCTION

Having a preterm birth is associated with future cardiovascular risk. Non-Hispanic Black women have higher rates of preterm birth than non-Hispanic White and Hispanic women, but nativity-related disparities in preterm birth are not well understood.

METHODS

Data from 6,096 women in the Boston Birth Cohort: non-Hispanic Black (2,699), non-Hispanic White (997), or Hispanic (2,400), were analyzed in June 2021. Differences in cardiovascular risk factors were assessed. The association of preterm birth with nativity and duration of U.S. residence were investigated using multivariable logistic regression.

RESULTS

U.S.-born women in all 3 racial-ethnic groups had a higher prevalence of obesity, smoking, and severe stress than foreign-born women. Foreign-born non-Hispanic Black and Hispanic women had lower odds of preterm birth than U.S.-born counterparts (non-Hispanic Black: AOR=0.79, 95% CI=0.65, 0.97; Hispanic: AOR=0.72, 95% CI=0.56, 0.93). In all the 3 groups, foreign-born women with shorter (<10 years) duration of U.S. residence had lower odds of preterm birth than the U.S.-born women (non-Hispanic Black: AOR=0.57, 95% CI=0.43, 0.75; Hispanic: AOR=0.72, 95% CI=0.55, 0.94; non-Hispanic White: AOR=0.46, 95% CI=0.25, 0.85), whereas the odds of preterm birth in foreign-born women with ≥10 years of residence were not significantly different.

CONCLUSIONS

Foreign-born women had better cardiovascular risk profiles in all groups and lower odds of preterm birth in non-Hispanic Black and Hispanic groups. In all the 3 groups, a shorter duration of U.S. residence was associated with lower odds of preterm birth. Further studies are needed to understand the biological and social determinants underlying these nativity-related disparities and the impact of acculturation.

A Qualitative Study Documenting Black Birthing Individuals' Perspectives on the Disproportionate Rate of Preterm Birth in the Black Community

Background:

Compared with all other racial and ethnic groups, the rate of preterm birth (PTB) is 50% higher among non-Hispanic Blacks (NHB). There are limited published data focused on the etiology of the racial disparity in PTB from the perspective of Black birthing individuals who have had a lived experience with PTB.

Methods:

To gain insights into the etiology of the race disparity in PTB from the NHB patient's perspective, we conducted a qualitative descriptive study with NHBs who have a history of PTB. We conducted both focus group discussions (FGDs), in-depth interviews (IDIs), and used applied thematic analysis to analyze the data.

Results:

Seven individuals participated in 3 FGDs and 15 individuals participated in an IDI. The majority of participants named stress as a contributor to PTB among NHBs. Participants described that stress becomes an ongoing cycle with a cumulative effect on health. Three primary sources of stress were identified: (1) individual including stress from lack of personal wellness, (2) relational stress from intimate partner and familial relationships, and (3) community-level stress from occupations and societal expectations.

Conclusion:

Uncovering NHB patient's perspectives on the etiology of PTB is a critical step to develop interventions that mitigate the disparity impacting the Black community. Our findings suggest that multilevel interventions targeting individual-, relational-, and community-level stress may be necessary to reduce rates of PTB among NHB individuals.

Surfactant Protein (SP) induces preterm birth by promoting oxidative stress via upregulating Storkhead-Box Protein 1

Preterm birth is the leading cause of infant mortality. The mechanisms that instigate preterm birth remain elusive and this makes it difficult to predict or prevent preterm birth. In this study, the authors found that SP-A induced pathological damage to the placenta and promoted preterm birth. Through mechanism, SP-A promoted the expression of STOX1 which further promoted the oxidative stress in the placenta by inhibiting the activities of a series of antioxidant enzymes including SOD, CAT and GSH-Px. SP-A also induced dysregulation of arginine metabolism by inhibiting NOS2 and ARG2. Overexpression of STOX1 aggravated SP-A induced oxidative stress, pathological damage, and preterm birth, whereas knockdown of STOX1 alleviated SP-A induced oxidative stress, pathological damage and preterm birth. The present study uncovers that SP-A induces preterm birth by promoting oxidative stress via upregulating STOX1, which provides new targets for the prediction and prevention of preterm birth.

Effect of a Nonoptimal Cervicovaginal Microbiota and Psychosocial Stress on Recurrent Spontaneous Preterm Birth

OBJECTIVE

While select cervicovaginal microbiota and psychosocial factors have been associated with spontaneous preterm birth, their effect on the risk of recurrence remains unclear. It is also unknown whether psychosocial factors amplify underlying biologic risk. This study sought to determine the effect of nonoptimal cervicovaginal microbiota and perceived stress on the risk of recurrent spontaneous preterm birth.

STUDY DESIGN

This was a secondary analysis of a prospective pregnancy cohort, Motherhood and Microbiome. The Cohen's Perceived Stress Scale (PSS-14) was administered and cervical swabs were obtained between 16 and 20 weeks of gestation. PSS-14 scores ≥30 reflected high perceived stress. We analyzed cervicovaginal microbiota using 16S rRNA sequencing and classified microbial communities into community state types (CSTs). CST IV is a nonoptimal cervicovaginal microbial community characterized by anaerobes and a lack of Lactobacillus. The final cohort included a predominantly non-Hispanic Black population of women with prior spontaneous preterm birth who had recurrent spontaneous preterm birth or term birth and had stress measurements (n = 181). A subanalysis was performed in the subset of these women with cervicovaginal microbiota data (n = 74). Multivariable logistic regression modeled adjusted associations between CST IV and recurrent spontaneous preterm birth, high stress and recurrent spontaneous preterm birth, as well as high stress and CST IV.

RESULTS

Among the 181 women with prior spontaneous preterm birth, 45 (24.9%) had high perceived stress. We did not detect a significant association between high stress and recurrent spontaneous preterm birth (adjusted odds ratio [aOR] 1.67, 95% confidence interval [CI]: 0.73-3.85). Among the 74 women with prior spontaneous preterm birth and cervicovaginal microbiota analyzed, 29 (39.2%) had CST IV; this proportion differed significantly among women with recurrent spontaneous preterm birth (51.4%) compared with women with term birth (28.2%) (p = 0.04). In models adjusted for race and marital status, the association between CST IV and recurrent spontaneous preterm birth persisted (aOR 3.58, 95% CI: 1.25-10.24). There was no significant interaction between stress and CST IV on the odds of spontaneous preterm birth (p = 0.328). When both stress and CST IV were introduced into the model, their associations with recurrent spontaneous preterm birth were slightly stronger than when they were in the model alone. The aOR for stress with recurrent spontaneous preterm birth was 2.02 (95% CI: 0.61-6.71) and for CST IV the aOR was 3.83 (95% CI: 1.30-11.33). Compared to women with neither of the two exposures, women with both high stress and CST IV had the highest odds of recurrent spontaneous preterm birth (aOR = 6.01, 95% CI: 1.002-36.03).

CONCLUSION

Among a predominantly non-Hispanic Black cohort of women with a prior spontaneous preterm birth, a nonoptimal cervicovaginal microbiota is associated with increased odds of recurrent spontaneous preterm birth. Adjustment for perceived stress may amplify associations between CST IV and recurrent spontaneous preterm birth. Identification of modifiable social or behavioral factors may unveil novel nonpharmacologic interventions to decrease recurrent spontaneous preterm birth among women with underlying biologic risk.

KEY POINTS

· CST IV, a nonoptimal microbiota, is associated with increased odds of recurrent spontaneous preterm birth.. · Adjustment for perceived stress amplified associations between CST IV and recurrent spontaneous preterm birth.. · Identification of modifiable psychosocial factors may unveil novel nonpharmacologic interventions to decrease recurrent preterm birth..

Maternal exposure to childhood traumatic events, but not multi-domain psychosocial stressors, predict placental corticotrophin releasing hormone across pregnancy

Maternal psychosocial stress increases the risk of adverse birth and postnatal outcomes for the mother and child, but the role of maternal exposure to childhood traumatic events (CTE) and multi-domain psychosocial stressors for the level and rise of placental Corticotrophin-Releasing Hormone (pCRH) across pregnancy has been understudied. In a sociodemographically and racially diverse sample of 1303 women (64% Black, 36% White/others) with low-medical risk pregnancies at enrollment from Shelby County, Tennessee, USA, blood samples were drawn twice, corresponding roughly to second and third trimester, and extracted prior to conducting radioimmune assays for pCRH. Mothers reported CTE (physical abuse, sexual abuse, or family violence, in childhood), adulthood traumatic events, and interpersonal violence during pregnancy. Neighborhood crime/deprivation was derived using geospatially-linked objective databases. General linear and mixed models tested associations between stress exposure variables and pCRH levels and rate of rise, adjusting for obstetric/clinical/health related factors. Maternal CTE did not predict pCRH levels at time 1, but positively predicted levels at time 2, and the rate of rise in pCRH across pregnancy. Race did not moderate this association. No additional maternal stress exposures across adulthood or during pregnancy predicted pCRH outcomes. Findings indicate that childhood violence or abuse exposure can become biologically embedded in a manner predicting later prenatal physiology relevant for maternal and offspring health, and that such embedding may be specific to childhood, but not adulthood, stress. Findings also highlight the placental-fetal unit as a mechanistic pathway through which intergenerational transmission of the adverse effects of childhood adversities may occur.

Psychosocial Stress and Preterm Birth: The Impact of Parity and Race

Objectives Studies examining risk factors for preterm birth (PTB) such as psychosocial stress are often focused on women with a history of PTB; however, most preterm babies are born to women with no history of preterm birth. Our objective was to determine if the relationship between psychosocial stress and PTB is altered by parity. Non-Hispanic black (NHB) women have increased psychosocial stress and PTB; therefore, we further aimed to determine if race alters the relationship between psychosocial stress, parity, and PTB. Methods We performed a secondary analysis of the Healthy Pregnancy, Healthy Baby Study comparing pregnant women who were primiparous (first pregnancy), multiparous with history of preterm birth, or multiparous with history of term birth. Perceived stress, perceived racism, interpersonal support, John Henryism and self-efficacy were measured using validated instruments. Logistic regression was used to model the effect of psychosocial stress on PTB stratified by parity and race. Results The analysis entire cohort included 1606 subjects, 426 were primiparous, 268 had a history of presterm birth, and 912 had a history of term birth. In women with a history of term birth, higher self-efficacy was associated with lower odds of spontaneous PTB, and this association was amplified in NHB women. In women with a history of spontaneous PTB, John Henryism Active Coping was associated with lower odds of spontaneous PTB in the index pregnancy. Conclusions for Practice The relationship between psychosocial stress and PTB may be mediated by parity and race.

Effects of corticotropin-releasing hormone on the expression of adenosine triphosphate-sensitive potassium channels (Kir6.1/SUR2B) in human term pregnant myometrium

Objective

Corticotropin-releasing hormone (CRH) is a crucial regulator of human pregnancy and parturition. Adenosine triphosphate (ATP)-sensitive potassium (KATP) channels are important for regulating myometrial quiescence during pregnancy. We investigated regulatory effects of different concentrations of CRH on KATP channel expression in human myometrial smooth muscle cells (HSMCs) in in vitro conditions.

Methods

After treating HSMCs with different concentrations of CRH (1, 10, 10², 10³, 10⁴ pmol/L), mRNA and protein expression of K_ATP channel subunits (Kir6.1 and SUR2B) was analyzed by reverse transcription-polymerase chain reaction and western blot. We investigated which CRH receptor was involved in the reaction and measured the effects of CRH on intracellular Ca²⁺ concentration when oxytocin was administered in HSMCs using Fluo-8 AM ester.

Results

When HSMCs were treated with low (1 pmol/L) and high (10³, 10⁴ pmol/L) CRH concentrations, K_ATP channel expression significantly increased and decreased, respectively. SUR2B mRNA expression at low and high CRH concentrations was significantly antagonized by antalarmin (CRH receptor-1 antagonist) and astressin 2b (CRH receptor-2 antagonist), respectively; however, Kir6.1 mRNA expression was not affected. After oxytocin treatment, the intracellular Ca²⁺ concentration in CRH-treated HSMCs was significantly lowered in low concentration of CRH (1 pmol/L), but not in high concentration of CRH (10³ pmol/L), compared to control.

Conclusion

Our data demonstrated the regulatory effect was different when HSMCs were treated with low (early pregnancy-like) and high (labor-like) CRH concentrations and the KATP channel expression showed significant increase and decrease. This could cause inhibition and activation, respectively, of uterine muscle contraction, demonstrating opposite dual actions of CRH.

Genetics, hormonal influences, and preterm birth

Prematurity is a devastating disease with high neonatal morbidity and mortality based on gestational age at birth. Genetic and hormonal signals impact directly on the maternal predisposition to preterm birth or sudden onset of myometrial contractility. Candidate gene or genome-wide approaches are beginning to identify potential variants for women at risk for premature delivery or increased responsiveness to hormonal signals including progesterone. However, a majority of these studies have not yielded definitive results to allow for at this stage for development of personalized therapy.

Childhood stress and birth timing among African American women: Cortisol as biological mediator

Preterm birth (PTB) occurs among 1:11U.S. white women and 1:7.5 African American women and is a significant driver of racial disparities in infant mortality. Maternal stress is the most common clinical phenotype underlying spontaneous PTB. Specific patterns of stress and biological mediators driving PTB remain unclear. We examined the effect of childhood stress on birth timing among African American women and evaluated maternal cortisol elevation as a biological mediator. A prospective observational design was employed, with a single study visit at 28-32 weeks gestation and medical record review. The Stress and Adversity Inventory was administered, which provides a comprehensive estimate of childhood stress, stress in adulthood, and five core characteristic subscales (interpersonal loss, physical danger, humiliation, entrapment, role disruption). Venipuncture was performed between 11:00am and 4:00pm and plasma cortisol quantified by ELISA. Analyses controlled for stress in adulthood. Among a final sample of 89, cumulative childhood stress predicted birth timing (p=0.01). The association was driven by stress related to interpersonal loss and physical danger, with support for maternal cortisol as a biological mediator (ab=0.02, 95% CI [0.001, 0.045]; ab=0.02, 95% CI [0.001, 0.043], respectively). Results were similar, overall, in sub-group analyses among spontaneously laboring women (n=53); however, role disruption arose as an additional predictor, as mediated by cortisol elevations (ab=0.03, 95% CI [0.005, 0.074]). Of note, cortisol was no longer supported as a mediator linking physical danger to birth timing after adjusting for sleep quality and hours awake prior to venipuncture (ab=0.02, 95% CI [-0.0001, 0.046]). We provide preliminary evidence that, independent of stress in adulthood, childhood stress of specific core characteristics may shape birth timing, with cortisol elevation as a biological mediator. Further investigation is warranted and may bolster the development of biologically-informed screening tools for the prediction and targeted prevention of stress-related PTB.

Gestation-related psychosocial factors in women from Medellin, Colombia

INTRODUCTION

Perinatal stress and the impact generated by adverse conditions could affect fetal development negatively with long term and short term manifestations and could increase the risk of maternal depression.

OBJECTIVE

To determine the psychosocial risk factors present in women with high-obstetric risk and hospitalized in a high complexity institution.

METHODS

A cross-sectional study that included 112 pregnant or immediate postpartum women, who were evaluated using a scale designed by the researchers and the Edinburgh Postnatal Depression Scale.

RESULTS

Median age was 24 (RIC 9) years; 39.3% of the women were pregnant, and 65.9% had a gestational age of more than 28 weeks. The main reason for hospitalization was threat of preterm delivery in 39.2%. 52.4% planned the pregnancy and 22.3% had depressive symptoms compatible with depression. Suicidal ideas and suicide attempts were more prevalent in the first trimester (7.2% and 3.6%).

DISCUSSION

The high prevalence of depressive symptoms in the population studied coincides with what was reported in similar studies in Latin America. The fact that pregnancy does not protect against suicide was confirmed.

CONCLUSIONS

Psychosocial screening is recommended in every pregnant woman and women in immediate postpartum to detect symptoms and risk factors for depression.

Effect of Vocalization of the Holy Quran With and Without Translation on Pregnancy Outcomes: A Randomized Clinical Trial

Background

During recent decades, research in Iran in the area of the Quran and medical science has been seriously engaged in. With respect to the tendency toward spirituality and alternative medicine, we tried to find other aspects of the influence of the Quran.

Objectives

This study aimed to determine the effect of vocalizations of the Holy Quran with and without translation on the consequences of pregnancy (the prevalence of preterm delivery, caesarean delivery, and neonatal anthropometric indices) in women admitted to health care centers in Urmia, Iran.

Materials and Methods

This was a three-armed parallel-group randomized clinical trial in which 168 pregnant women (25-28 weeks) in their first and second pregnancies were divided into three groups of 56 (Holy Quran with translation, Holy Quran without translation, and control group) by randomized blocking. The intervention was implemented once a week for three weeks in the health center, and on other days of the week, the participants listened at home to a CD they were given. The intervention and the control groups all received routine pregnancy care once a week. These mothers were tracked during their labor. Outcomes including gestational age at delivery, delivery type, and neonatal anthropometric indices were recorded based on the mother’s records.

Results

There was no statistically significant difference between the groups in terms of demographic and obstetric characteristics before the intervention. In comparison with the control group, the probability of preterm delivery was lower in the Holy Quran with translation group (odds ratio: 0.3, CI 95%: 0.1-1.2) and in the Holy Quran without translation group (0.6, 0.2-1.9) as compared to the control group. However, this difference was not statistically significant. Similarly, the probability of caesarean delivery was lower in the Holy Quran with translation group (0.6, 0.3-1.4) and the Holy Quran without translation group (0.5, 0.2-1.2) as compared to the control group. Based on one-way ANOVA, there was no statistically significant difference between the study groups regarding the infants’ anthropometric indices.

Conclusions

Based on the results of this study, despite the lower prevalence of preterm labor and caesarean section in the intervention groups as compared to the control group, no statistically significant effect was seen. This was apparently due to the small sample size.

Treatment with serotonin reuptake inhibitors during pregnancy is associated with elevated corticotropin-releasing hormone levels

Treatment with serotonin reuptake inhibitors (SSRI) has been associated with an increased risk of preterm birth, but causality remains unclear. While placental CRH production is correlated with gestational length and preterm birth, it has been difficult to establish if psychological stress or mental health problems are associated with increased CRH levels. This study compared second trimester CRH serum concentrations in pregnant women on SSRI treatment (n=207) with untreated depressed women (n=56) and controls (n=609). A secondary aim was to investigate the combined effect of SSRI treatment and CRH levels on gestational length and risk for preterm birth. Women on SSRI treatment had significantly higher second trimester CRH levels than controls, and untreated depressed women. CRH levels and SSRI treatment were independently associated with shorter gestational length. The combined effect of SSRI treatment and high CRH levels yielded the highest risk estimate for preterm birth. SSRI treatment during pregnancy is associated with increased CRH levels. However, the elevated risk for preterm birth in SSRI users appear not to be mediated by increased placental CRH production, instead CRH appear as an independent risk factor for shorter gestational length and preterm birth.

Preterm and postterm birth in immigrant- and Swedish-born parents: a population register-based study

Ethnic minorities/immigrant groups tend to have increased risk for preterm birth. Less is known about this risk in diverse immigrant groups, couples of mixed ethnic-origin and in relation to duration of residence. Data from the Swedish Medical Birth Register on 1,028,303 mothers who gave birth to 1,766,026 singleton live born infants (1982-2002), was linked to the Education and Total Population Registers. Immigrant parents were identified by country of birth. Risk of early preterm, late preterm and postterm birth was analyzed using multinomial logistic regression. Polish, Yugoslavian, Iranian, South Asian, East Asian and Sub-Saharan African parents, Swedish mothers who had children with non-Swedish fathers, and parents from two different immigrant groups had higher risk of early preterm birth [adjusted relative risk (RR) (95% CI) 1.76 (1.24-2.50), 1.57 (1.31-1.87), 1.67 (1.30-2.14), 1.52 (1.07-2.16), 1.51 (1.08-2.10), 2.03 (1.32-3.12), 1.56 (1.45-1.67), and 1.55 (1.35-1.77) respectively] compared to Swedish-born parents. South Asian, Sub-Saharan African, and East Asian immigrants had a higher risk of late preterm birth compared to Swedish-born parents. North African and Middle Eastern, Somali, and Ethiopian/Eritrean groups had increased risk of postterm birth [adjusted RR 1.31 (1.16-1.47), 2.57 (2.31-2.86), 1.85 (1.67-2.04) respectively]. Adjustment for covariates did not substantially change associations. Immigrant mothers resident <3 years had higher risk for early preterm and postterm birth compared to residents >10 years [adjusted RR 1.46 (1.24-1.71) and 1.16 (1.11-1.23) respectively]. In addition to higher risk of preterm birth in select immigrant groups, some immigrant groups are also at higher risk of postterm birth. Shorter duration of residence is associated with higher risk of non-term deliveries.

Psychosocial stress in pregnancy and preterm birth: associations and mechanisms

AIMS

Psychosocial stress during pregnancy (PSP) is a risk factor of growing interest in the etiology of preterm birth (PTB). This literature review assesses the published evidence concerning the association between PSP and PTB, highlighting established and hypothesized physiological pathways mediating this association.

METHOD

The PubMed and Web of Science databases were searched using the keywords "psychosocial stress", "pregnancy", "pregnancy stress", "preterm", "preterm birth", "gestational age", "anxiety", and "social support". After applying the exclusion criteria, the search produced 107 articles.

RESULTS

The association of PSP with PTB varied according to the dimensions and timing of PSP. Stronger associations were generally found in early pregnancy, and most studies demonstrating positive results found moderate effect sizes, with risk ratios between 1.2 and 2.1. Subjective perception of stress and pregnancy-related anxiety appeared to be the stress measures most closely associated with PTB. Potential physiological pathways identified included behavioral, infectious, neuroinflammatory, and neuroendocrine mechanisms.

CONCLUSIONS

Future research should examine the biological pathways of these different psychosocial stress dimensions and at multiple time points across pregnancy. Culture-independent characterization of the vaginal microbiome and noninvasive monitoring of cholinergic activity represent two exciting frontiers in this research.

CRH activation of different signaling pathways results in differential calcium signaling in human pregnant myometrium before and during labor

CONTEXT

Our previous study has demonstrated that CRH has differential effects on human uterine contractility before and after onset of labor. Intracellular Ca2+ concentration ([Ca2+]i) mobilization plays an important role in the control of uterine contraction.

OBJECTIVE

Our objective was to investigate the effects of CRH on [Ca2+]i homeostasis in laboring and nonlaboring myometrial cells and determine subsequent signaling involved in [Ca2+]i regulation by CRH.

DESIGN

The myometrial tissues were obtained from pregnant women who were undergoing or not undergoing labor at term. [Ca2+]i was determined by Ca2+ imaging system using the fluorescent dye fura-2-acetoxymethyl ester. Western blot analysis, ELISA, and RIA were used to determine the signaling pathways induced by CRH.

RESULTS

CRH induced Ca2+ transient in laboring cells, which was blocked by CRH receptor type 1 (CRHR1) antagonist antalarmin. CRHR1 knockdown impaired this effect of CRH. CRH activated Gi protein, decreased cAMP production, and induced phosphorylated phospholipase C-β3 and inositol-1,4,5-triphosphate production. Phospholipase C and inositol-1,4,5-triphosphate receptor inhibitors blocked the CRH-induced Ca2+ transient in laboring cells. CRH did not induce whereas antalarmin induced the Ca2+ transient in nonlaboring cells. Knockdown of CRHR1 impaired the effect of antalarmin. CRH acted on CRHR1 to activate Gs in nonlaboring cells. Forskolin blocked antalarmin-induced Ca2+ transient.

CONCLUSIONS

CRH acts on CRHR1 to activate different signaling pathways before and after onset of labor, thereby resulting in differential calcium signaling in response to CRH. The signaling pathways of CRHR1 might serve as a target for the development of new therapeutic strategies for preterm birth.

Adverse perinatal outcomes after the February 27th 2010 Chilean earthquake

OBJECTIVE

To investigate whether the February 27th earthquake exposition was associated to adverse perinatal outcomes in Chilean pregnant women.

METHODS

We analyzed all deliveries occurred in 2009 (n = 3,609) and 2010 (n = 3,279) in a reference hospital in the area of the earthquake. Furthermore, we investigated pregnant women who gave birth between March 1st and December 31st 2010 (n = 2,553) and we classified them according to timing of exposition.

RESULTS

We found a 9% reduction in birth rate, but an increase in the rate of early preterm deliveries (<34 weeks), premature rupture of membranes (PROM), macrosomia, small for gestational age, and intrauterine growth restriction (IUGR) after the earthquake, in contrast to the previous year. Women exposed to the earthquake during her first trimester delivered smaller newborns (3,340 ± 712 g v/s 3,426 ± 576 g respectively, p = 0.007) and were more likely diagnosed with early preterm delivery, preterm delivery (<37 weeks) and PROM but were less likely diagnosed with IUGR and late delivery (42 weeks, p < 0.05) compared to those exposed at third trimester. Accordingly, IUGR and preterm deliveries presented elevated healthcare costs.

CONCLUSION

Natural disasters such as earthquakes are associated to adverse perinatal outcomes that impact negatively the entire maternal-neonatal healthcare system.

Preconceptional stress and racial disparities in preterm birth: an overview

OBJECTIVE

We reviewed the evidence for three theories of how preconceptional psychosocial stress could act as a contributing determinant of excess preterm birth risk among African American women: early life developmental plasticity and epigenetic programming of adult neuroendocrine systems; blunting, weathering, or dysfunction of neuroendocrine and immune function in response to chronic stress activation through the life course; individuals' adoption of risky behaviors such as smoking as a response to stressful stimuli.

METHODS

Basic science, clinical, and epidemiologic studies indexed in MEDLINE and Web of Science databases on preconceptional psychosocial stress, preterm birth and race were reviewed.

RESULTS

Mixed evidence leans towards modest associations between preconceptional chronic stress and preterm birth (for example common odds ratios of 1.2-1.4), particularly in African American women, but it is unclear whether this association is causal or explains a substantial portion of the Black-White racial disparity in preterm birth. The stress-preterm birth association may be mediated by hypothalamic-pituitary-adrenal axis dysfunction and susceptibility to bacterial vaginosis, although these mechanisms are incompletely understood. Evidence for the role of epigenetic or early life programming as a determinant of racial disparities in preterm birth risk is more circumstantial.

CONCLUSIONS

Preconceptional stress, directly or in interaction with host genetic susceptibility or infection, remains an important hypothesized risk factor for understanding and reducing racial disparities in preterm birth. Future studies that integrate adequately sized epidemiologic samples with measures of stress, infection, and gene expression, will advance our knowledge and allow development of targeted interventions.

The use of psychosocial stress scales in preterm birth research

Psychosocial stress has been identified as a potential risk factor for preterm birth. However, an association has not been found consistently, and a consensus on the extent to which stress and preterm birth are linked is still lacking. A literature search was performed with a combination of keywords and MeSH terms to detect studies of psychosocial stress and preterm birth. Studies were included in the review if psychosocial stress was measured with a standardized, validated instrument and if the outcomes included either preterm birth or low birthweight. Within the 138 studies that met inclusion criteria, 85 different instruments were used. Measures that had been designed specifically for pregnancy were used infrequently, although scales were sometimes modified for the pregnant population. The many different measures that have been used may be a factor that accounts for the inconsistent associations that have been observed.

The contribution of maternal stress to preterm birth: issues and considerations

Preterm birth represents the most significant problem in maternal-child health, with maternal stress identified as a variable of interest. The effects of maternal stress on risk of preterm birth may vary as a function of context. This article focuses on select key issues and questions highlighting the need to develop a better understanding of which particular subgroups of pregnant women may be especially vulnerable to the potentially detrimental effects of maternal stress, and under what circumstances and at which stages of gestation. Issues related to the characterization and assessment of maternal stress and candidate biologic mechanisms are addressed.

Elevated corticotropin releasing hormone (CRH) during pregnancy and risk of postpartum depression (PPD)

CONTEXT

Perinatal depression has a prevalence of 10% with devastating consequences for mother and baby. The prospective identification of those at risk for postpartum (PPD) or prenatal (PND) depression has led to biomarker searches in pregnancy. There are conflicting reports of associations between midpregnancy placental CRH (pCRH) and PPD or PND.

OBJECTIVE

The objective of the study was to quantify the association of maternal pCRH with PPD and PND.

DESIGN

This was a prospective cohort study (the Pregnancy, Infection, and Nutrition Study).

SETTING

The study was conducted at a prenatal clinics at the University of North Carolina at Chapel Hill.

PATIENTS

Patients included 1230 pregnant women.

MAIN OUTCOME MEASURES

The relationship between pCRH at less than 20 wk and 24-29 wk and maternal depression assessed in pregnancy [Center for Epidemiologic Studies Depression Scale (CES-D)] and postpartum (12 wk and 1 yr) with the Edinburgh Postnatal Depression Scale (EPDS).

RESULTS

At 24-29 wk, 24.8% of women had CES-D score of 17 or greater, and 9.7% had a CES-D score of 25 or greater. At 12 wk postpartum, 18.2% of women had an EPDS score of 10 or greater and 7.6% had an EPDS score of 13 or greater. CRH measures at less than 20 wk and 24-29 wk were inversely correlated with a CES-D score at 24-29 wk (n = 1080, P < 0.05 and P < 0.01, respectively). Pregnancy pCRH was not correlated with the EPDS score at 12 wk (n = 484) or 1 yr postpartum (n = 391). In covariate-adjusted models, higher pCRH was not associated with a CES-D of 17 or greater at 24-29 wk (odds ratio 0.88 per sd change in pCRH at 24-29 wk, 95% confidence interval 0.76-1.03). There was no association between log CRH at 24-29 wk and PPD (covariate-adjusted odds ratio per sd 0.99, 95% confidence interval 0.69-1.42).

CONCLUSION

Higher midpregnancy pCRH was not associated with an increased risk of PND or PPD.

Levels of maternal serum corticotropin-releasing hormone (CRH) at midpregnancy in relation to maternal characteristics

BACKGROUND

Corticotropin-releasing hormone (CRH) in maternal blood originates primarily from gestational tissues and elevated levels in midpregnancy have been linked to adverse pregnancy outcomes. Investigators have hypothesized that high levels of maternal stress might lead to elevated CRH levels in pregnancy. Yet a few studies have measured maternal CRH levels among subgroups of women who experience disproportionate socioeconomic disadvantage, such as African-American and Hispanic women, and found that these groups have lower CRH levels in pregnancy. Our goal was to identify maternal characteristics related to CRH levels in midpregnancy and examine which if any of these factors help to explain race differences in CRH levels.

METHODS

The Pregnancy Outcomes and Community Health (POUCH) Study prospectively enrolled women at 15-27 weeks' gestation from 52 clinics in five Michigan communities (1998-2004). Data from the POUCH Study were used to examine maternal demographics, anthropometrics, health behaviors, and psychosocial factors (independent variables) in relation to midpregnancy blood CRH levels modeled as logCRHpg/ml (dependent variable). Analyses were conducted within a sub-cohort from the POUCH Study (671 non-Hispanic Whites, 545 African-Americans) and repeated in the sub-cohort subset with uncomplicated pregnancies (n=746). Blood levels of CRH and independent variables were ascertained at the time of enrollment. All regression models included week of enrollment as a covariate. In addition, final multivariate regression models alternately incorporated different psychosocial measures along with maternal demographics and weight. Psychosocial variables included measures of current depressive symptoms, perceived stress, coping style, hostility, mastery, anomie, and a chronic stressor (history of abuse as a child and adult).

RESULTS

In sub-cohort models, the adjusted mean log CRH level was significantly lower in African-Americans vs. non-Hispanic Whites; the difference was -0.48pg/ml (P<0.01). This difference was reduced by 21% (-0.38pg/ml, P<0.01) after inclusion of other relevant covariates. Adjusted mean log CRH levels were also lower among women with <12 years vs. >or=12 years of education (minimal difference=-0.19pg/ml, P<0.05), and among women with high levels of depressive symptoms who did not use antidepressants vs. women with lower levels of depressive symptoms and no antidepressant use (minimal difference=-0.13pg/ml, P<0.01). Log CRH levels were inversely associated with maternal weight (-0.03pg/ml per 10 pound increase, P<.05) but unrelated to smoking and all other psychosocial measures. Results were similar in the subset of women with uncomplicated pregnancies, except that lower CRH levels were also linked to higher perceived stress.

CONCLUSION

African-American women have lower blood CRH levels at midpregnancy and the race difference in CRH levels is reduced modestly after adjustment for other maternal characteristics. CRH levels were not elevated among women with high levels of perceived stress or more chronic stressors. The inverse association between CRH levels and maternal weight is likely due to a hemodilution effect. Relations among maternal CRH levels and maternal race, educational level, and depressive symptoms are difficult to explain and invite further investigation. Our results highlight a group of covariates that merit consideration in studies that address CRH in the context of pregnancy and/or post-partum complications.

Non-stress-related factors associated with maternal corticotrophin-releasing hormone (CRH) concentration

During pregnancy, most maternal corticotrophin-releasing hormone (CRH) is secreted by the placenta, not the hypothalamus. Second trimester maternal CRH concentration is robustly associated with the subsequent risk of preterm birth, and it is often assumed that physiological and/or psychological stress stimulates placental CRH release. Evidence supporting the latter assumption is weak, however, and other factors affecting maternal CRH have received little attention from investigators. We carried out a case-control study nested within a large, multicentre prospective cohort of pregnant women to examine potential 'upstream' factors associated with maternal CRH concentration measured at 24-26 weeks of gestation. The predictors studied included maternal age, parity, birthplace (as a proxy for ethnic origin), pre-pregnancy body mass index, height, smoking, bacterial vaginosis and vaginal fetal fibronectin (FFN) concentration. Women with high (above the median) plasma CRH concentration were significantly less likely to have been born in Sub-Saharan Africa or the Caribbean, less likely to be overweight or obese, and more likely to be smokers. Associations with maternal birthplace and BMI persisted in logistic regression analyses controlling for potential confounding variables and when restricted to term controls. A strong (but imprecise and statistically non-significant) association was also observed with high vaginal FFN concentration. Further studies are indicated both in animal models and human populations to better understand the biochemical and physiological pathways to CRH secretion and their aetiological role, if any, in preterm birth.