Hormone trajectories leading to human birth

The interplay of oxytocin and sex hormones

The neuropeptide oxytocin has historically been associated with reproduction and maternal behavior. However, more recent research has uncovered that oxytocin has a much wider range of roles in physiology and behavior. Despite the excitement surrounding potential therapeutical applications of intranasally administered oxytocin, the results of these intervention studies have been inconsistent. Various reasons for these mixed results have been proposed, which tend to focus on methodological issues, such as study design. While methodological issues are certainly important, emerging evidence suggests that the interaction between oxytocin and sex hormones may also account for these varied findings. To better understand the purpose and function of the interaction of oxytocin with sex hormones, with a focus on estrogens, progesterone, and testosterone, we conducted a comprehensive thematic review via four perspectives: evolutionary, developmental, mechanistic, and survival. Altogether, this synergistic approach highlights the critical function of sex hormone activity for accomplishing the diverse roles of oxytocin via the modulation of oxytocin release and oxytocin receptor activity, which is also likely to contribute to the heterogeneity of outcomes after oxytocin administration.

Challenges in timing and mode of delivery in morbidly obese women

Globally obesity is increasing especially in the reproductive age group. Pregnant women with obesity have higher complication and intervention rates. They are also at increased risk of stillbirth and intrapartum complications. Although organisations like NICE, RCOG, ACOG and WHO have published guidelines and recommendations on care of pregnant women with obesity the evidence from which Grade A recommendations can be made on timing and how to deliver is limited. The current advice is therefore to have discussions with the woman on risks to help her make an informed decision about timing, place, and mode of delivery. Obesity is an independent risk factor for pregnancy complications including diabetes, hypertension and macrosomia. In those with these complications, the timing of delivery is often influenced by the severity of the complication. As an independent factor, population based observational studies in obese women have shown an increase in the risk of stillbirth. This risk increases linearly with weight from overweight through to class II obesity, but then rises sharply in those with class III obesity by at least 10-fold beyond 42 weeks when compared to normal weight women. This risk of stillbirth is notably higher in obese women from 34 weeks onwards compared to normal weight women. One modifiable risk factor for stillbirth as shown from various cohorts of pregnant women is prolonged pregnancy. Research has linked obesity to prolonged pregnancy. Although the exact mechanism is yet unknown some have linked this to maternal dysregulation of the hypothalamic pituitary adrenal axis leading to hormonal imbalance delaying parturition. For these women the two dilemmas are when and how best to deliver. In this review, we examine the evidence and make recommendations on the timing and mode of delivery in women with obesity. For class I obese women there are no differences in outcome with regards to timing and mode of delivery when compared to lean weight women. However, for class II and III obesity, planned induction or caesarean sections may be associated with a lower perinatal morbidity and mortality although this may be associated with an increased in maternal morbidity especially in class III obesity. Studies have shown that delivery by 39 weeks is associated with lower perinatal mortality compared to delivering after in these women. On balance the evidence would favour planned delivery (induction or caesarean section) before 40 weeks of gestation. In the morbidly obese, apart from the standard lower transverse skin incision for CS, there is evidence that a supraumbilical transverse incision may reduce morbidity but is less cosmetic. Irrespective of the option adopted, it is important to discuss the pros and cons of each.

Trajectory of prenatal anxiety and depression and its association with fetal growth development

BACKGROUND

The stability of anxiety and depression during pregnancy and the impact on women and offspring has been recognized, yet the distinction of impact between them remains unclear. The aim of this study was to investigate the trajectory of prenatal anxiety and depression and their coexistence, as well as to examine the potential variations in pregnancy outcomes and fetal/neonatal growth development.

METHOD

At baseline (11-13+6 weeks), women were recruited and subsequently monitored in the second (16-20+6 weeks) and third (28-31+6 weeks) trimesters. Anxiety and depression were measured using the Hospital Anxiety and Depression Scale. In the second (16-20+6 weeks), third (28-31+6 weeks), and prenatal period (37-40+6 weeks), fetal growth was assessed by ultrasound scans. The joint trajectory model was used to determine the trajectory groups of depressive/anxiety dominant or coexistence. Comparisons of fetal/neonatal growth between groups were conducted using analysis of covariance and a multilevel model.

RESULT

A total of 457 pregnant women were finally included. Four trajectory groups were identified: none-negative emotion (n = 190, 41.6 %), anxiety dominant (n = 195, 42.6 %), depression dominant (n = 33, 7.2 %), and anxiety and depression coexistence (n = 39, 8.6 %). There were significant differences in the antenatal abdominal circumference (335.44 vs 333.92 vs 330.82 vs 325.13 mm, p = 0.007) of fetuses and the birth length (50.14 vs 50.03 vs 49.91 vs 49.18, p = 0.008) of newborns among four groups, showing a clear decreasing trend. Anxiety and depression coexistence displayed a notable and statistically significant difference when compared to the other groups and had a lower increase of fetal abdominal circumference (β = -8.91, 95%CI: -16.15, -1.67, p = 0.016) after controlling for confounding factors. Anxiety and depression dominant groups found no difference in fetal/neonatal growth.

CONCLUSIONS

The more severe the negative emotional state of mothers, the more restricted their offspring's development, especially in terms of fetal abdominal circumference and birth length. The impact of anxiety or depressive symptoms does not show a pronounced difference. However, what is noteworthy is the tendency and evident impact on offspring development when anxiety and depression coexistence work synergistically. As a result, healthcare professionals should place greater emphasis on addressing anxiety and depression in expectant mothers, particularly among those experiencing anxiety and depression coexisting symptoms.

Prenatal phthalate exposure in relation to placental corticotropin releasing hormone (pCRH) in the CANDLE cohort

CONTEXT

Phthalates may disrupt maternal-fetal-placental endocrine pathways, affecting pregnancy outcomes and child development. Placental corticotropin releasing hormone (pCRH) is critical for healthy pregnancy and child development, but understudied as a target of endocrine disruption.

OBJECTIVE

To examine phthalate metabolite concentrations (as mixtures and individually) in relation to pCRH.

DESIGN

Secondary data analysis from a prospective cohort study.

SETTING

Prenatal clinics in Tennessee, USA.

PATIENTS

1018 pregnant women (61.4% non-Hispanic Black, 32% non-Hispanic White, 6.6% other) participated in the CANDLE study and provided data. Inclusion criteria included: low-medical-risk singleton pregnancy, age 16-40, and gestational weeks 16-29.

INTERVENTION

None.

MAIN OUTCOME MEASURES

Plasma pCRH at two visits (mean gestational ages 23.0 and 31.8 weeks) and change in pCRH between visits (ΔpCRH).

RESULTS

In weighted quantile sums (WQS) regression models, phthalate mixtures were associated with higher pCRH at Visit 1 (β = 0.07, 95 %CI: 0.02, 0.11) but lower pCRH at Visit 2 (β = -0.08, 95 %CI: -0.14, -0.02). In stratified analyses, among women with gestational diabetes (n = 59), phthalate mixtures were associated with lower pCRH at Visit 1 (β = -0.17, 95 %CI: -0.35, 0.0006) and Visit 2 (β = -0.35, 95 %CI: -0.50, -0.19), as well as greater ΔpCRH (β = 0.16, 95 %CI: 0.07, 0.25). Among women with gestational hypertension (n = 102), phthalate mixtures were associated with higher pCRH at Visit 1 (β = 0.20, 95 %CI: 0.03, 0.36) and Visit 2 (β = 0.42; 95 %CI: 0.19, 0.64) and lower ΔpCRH (β = -0.17, 95 %CI: -0.29, -0.06). Significant interactions between individual phthalate metabolites and pregnancy complications were observed.

CONCLUSIONS

Phthalates may impact placental CRH secretion, with differing effects across pregnancy. Differences in results between women with and without gestational diabetes and gestational hypertension suggest a need for further research examining whether women with pregnancy complications may be more vulnerable to endocrine-disrupting effects of phthalates.

The Value of HPA Axis Hormones as Biomarkers for Screening and Early Diagnosis of Postpartum Depression: Updated Information About Methodology

Because of the high prevalence of postpartum depression (PPD) and the suffering involved, early diagnosis is urgent; however, current screening tools and diagnosis are inadequate. In addition to conventional methods such as the Edinburgh Postnatal Depression Scale and clinical interviews, several hormones in the hypothalamic-pituitary-adrenal (HPA) axis, such as corticotrophin-releasing hormone, adrenocorticotropic hormone, and cortisol, have been considered because of their critical roles in stress regulation in the mothers. The study designs are complicated, however, and so the effectiveness of these hormones as biomarkers for PPD is still controversial. Such inconsistency may have resulted from the variation in methodology between studies. The methodology problems in the investigation of PPD and HPA axis hormones have not been reported extensively. We therefore sought to summarize the methodological problems of studies published in the past decade, including the strengths and weaknesses of the examinations and the technological difficulties involved. Our findings suggest that (a) suitable samples and appropriate detection methods would reduce heterogeneity among trials; (b) the cutoff value of the scale test should be carefully selected for determining the performance of biomarker tests; (c) evaluation methods and criteria should be chosen with consideration of the tools feasible for use in local hospitals and population; and (d) the cost of diagnosis should be reduced. We hope that these findings provide insight for future investigations of HPA axis hormones as biomarkers for screening and early diagnosis of PPD.

Induction of labour in pregnant individuals with obesity

People with obesity may require induction of labour (IoL) due to a higher incidence of pre-existing comorbidities and pregnancy complications, as well as to prevent post-term pregnancies and late-term stillbirths. IoL at 39-40 weeks is associated with fewer caesarean births and lower morbidity for the pregnant person and neonate when compared with expectant management. Ensuring the success and safety of IoL in people with obesity requires adherence to evidence-based protocols for the management of labour induction and augmentation. Cervical ripening as well as the latent and active phases of labour in people with obesity may be considerably prolonged, requiring higher cumulative doses of oxytocin. This should be guided by intrauterine pressure catheters and early provision of neuraxial analgesia, where possible. There is insufficient evidence to recommend one method of IoL over another. The need for higher doses of prostaglandins and concurrent agents for cervical ripening should be studied in prospective studies.

Stress hormones mediate developmental plasticity in vertebrates with complex life cycles

The environment experienced by developing organisms can shape the timing and character of developmental processes, generating different phenotypes from the same genotype, each with different probabilities of survival and performance as adults. Chordates have two basic modes of development, indirect and direct. Species with indirect development, which includes most fishes and amphibians, have a complex life cycle with a free-swimming larva that is typically a growth stage, followed by a metamorphosis into the adult form. Species with direct development, which is an evolutionarily derived developmental mode, develop directly from embryo to the juvenile without an intervening larval stage. Among the best studied species with complex life cycles are the amphibians, especially the anurans (frogs and toads). Amphibian tadpoles are exposed to diverse biotic and abiotic factors in their developmental habitat. They have extensive capacity for developmental plasticity, which can lead to the expression of different, adaptive morphologies as tadpoles (polyphenism), variation in the timing of and size at metamorphosis, and carry-over effects on the phenotype of the juvenile/adult. The neuroendocrine stress axis plays a pivotal role in mediating environmental effects on amphibian development. Before initiating metamorphosis, if tadpoles are exposed to predators they upregulate production of the stress hormone corticosterone (CORT), which acts directly on the tail to cause it to grow, thereby increasing escape performance. When tadpoles reach a minimum body size to initiate metamorphosis they can vary the timing of transformation in relation to growth opportunity or mortality risk in the larval habitat. They do this by modulating the production of thyroid hormone (TH), the primary inducer of metamorphosis, and CORT, which synergizes with TH to promote tissue transformation. Hypophysiotropic neurons that release the stress neurohormone corticotropin-releasing factor (CRF) are activated in response to environmental stress (e.g., pond drying, food restriction, etc.), and CRF accelerates metamorphosis by directly inducing secretion of pituitary thyrotropin and corticotropin, thereby increasing secretion of TH and CORT. Although activation of the neuroendocrine stress axis promotes immediate survival in a deteriorating larval habitat, costs may be incurred such as reduced tadpole growth and size at metamorphosis. Small size at transformation can impair performance of the adult, reducing probability of survival in the terrestrial habitat, or fecundity. Furthermore, elevations in CORT in the tadpole caused by environmental stressors cause long term, stable changes in neuroendocrine function, behavior and physiology of the adult, which can affect fitness. Comparative studies show that the roles of stress hormones in developmental plasticity are conserved across vertebrate taxa including humans.

Cytokine profiling: variation in immune modulation with preterm birth vs. uncomplicated term birth identifies pivotal signals in pathogenesis of preterm birth

OBJECTIVES

To assess deviations in longitudinally measured cytokines with preterm birth (PTB).

METHODS

Prospective longitudinal study targeting 80 subjects. Phlebotomy specimens for broad panel of cytokine analysis were obtained at three time (T) intervals: first trimester (T1: 8-14 weeks' gestation), second trimester (T2: 18-22 weeks' gestation), and third trimester (T3: 28-32 weeks' gestation). Important demographics and outcomes were tracked. Data were stratified and the target groups were analyzed as follows: "Uncomplicated" (delivered ≥37 weeks) or "Preterm Birth" (<37 weeks). Generalized Linear Modeling determined rate of change T1-T3 by outcome.

RESULTS

Complete data replete with phlebotomy at all three visits were obtained on 80 women. Birth outcomes were as follows: 11 Uncomplicated Term Birth (UTB), 28 PTB, 4 low birth weight (LBW), 16 OB complications (OBC), 11 current infections (IFN), and 10 mixed complications (MC=2 or more of the above). 28 PTB were compared to 11 uncomplicated term deliveries. In both groups, T helper type 1 (TH1) cytokine (IL-1β), pleiotrophic pro-inflammatory cytokine (IL-6), and counter-regulatory cytokine (IL-10) responses decreased over gestation, but rates of change in IL-1β, IL-6, and IL-10 were significantly different. Stratification of women by smoking status additionally demonstrated significant variance in immune status over the course of pregnancy.

CONCLUSIONS

Women delivering PTB demonstrated significant differences in cytokine trajectory over pregnancy; these data further validate key role played by immune regulation in directing pregnancy outcome. Likewise, smoking impacts longitudinal trajectory of cytokines over pregnancy.

Placental Corticotrophin-Releasing Hormone is a Modulator of Fetal Liver Blood Perfusion

CONTEXT

Variation in fetal liver blood flow influences fetal growth and postnatal body composition. Placental corticotrophin-releasing hormone has been implicated as a key mediator of placental-fetal perfusion.

OBJECTIVE

To determine whether circulating levels of placental corticotrophin-releasing hormone across gestation are associated with variations in fetal liver blood flow.

DESIGN

Prospective cohort study.

METHODS

Fetal ultrasonography was performed at 30 weeks' gestation to characterize fetal liver blood flow (quantified by subtracting ductus venosus flow from umbilical vein flow). Placental corticotrophin-releasing hormone was measured in maternal circulation at approximately 12, 20, and 30 weeks' gestation. Multiple regression analysis was used to determine the proportion of variation in fetal liver blood flow explained by placental corticotrophin-releasing hormone. Covariates included maternal age, parity, pre-pregnancy body mass index, gestational weight gain, and fetal sex.

RESULTS

A total of 79 uncomplicated singleton pregnancies were analyzed. Fetal liver blood flow was 68.4 ± 36.0 mL/min (mean ± SD). Placental corticotrophin-releasing hormone concentrations at 12, 20, and 30 weeks were 12.5 ± 8.1, 35.7 ± 24.5, and 247.9 ± 167.8 pg/mL, respectively. Placental corticotrophin-releasing hormone at 30 weeks, but not at 12 and 20 weeks, was significantly and positively associated with fetal liver blood flow at 30 weeks (r = 0.319; P = 0.004) and explained 10.4% of the variance in fetal liver blood flow.

CONCLUSIONS

Placental corticotrophin-releasing hormone in late gestation is a possible modulator of fetal liver blood flow and may constitute a biochemical marker in clinical investigations of fetal growth and body composition.

Human Chorionic Gonadotropin Modulates the Transcriptome of the Myometrium and Cervix in Late Gestation

Human chorionic gonadotropin (hCG) is a critical hormone for the establishment and maintenance of pregnancy. hCG administration prevents the onset of preterm labor in mice; yet, the transcriptomic changes associated with this tocolytic effect that take place in the myometrium and cervix have not been elucidated. Herein, we implemented both discovery and targeted approaches to investigate the transcriptome of the myometrium and cervix after hCG administration. Pregnant mice were intraperitoneally injected with 10 IU of hCG on 13.0, 15.0, and 17.0 days post coitum, and the myometrium and cervix were collected. RNA sequencing was performed to determine differentially expressed genes, enriched biological processes, and impacted KEGG pathways. Multiplex qRT-PCR was performed to investigate the expression of targeted contractility- and inflammation-associated transcripts. hCG administration caused the differential expression of 720 genes in the myometrium. Among the downregulated genes, enriched biological processes were primarily associated with regulation of transcription. hCG administration downregulated key contractility genes, Gja1 and Oxtr, but upregulated the prostaglandin-related genes Ptgfr and Ptgs2 and altered the expression of inflammation-related genes in the myometrium. In the cervix, hCG administration caused differential expression of 3348 genes that were related to inflammation and host defense, among others. The downregulation of key contractility genes and upregulation of prostaglandin-related genes were also observed in the cervix. Thus, hCG exerts tocolytic and immunomodulatory effects in late gestation by altering biological processes in the myometrium and cervix, which should be taken into account when considering hCG as a potential treatment to prevent the premature onset of labor.

Pregnancy as a period of risk, adaptation, and resilience for mothers and infants

The pregnancy period represents a unique window of opportunity to identify risks to both the fetus and mother and to deter the intergenerational transmission of adversity and mental health problems. Although the maternal-fetal dyad is especially vulnerable to the effects of stress during pregnancy, less is known about how the dyad is also receptive to salutary, resilience-promoting influences. The present review adopts life span and intergenerational perspectives to review four key areas of research. The first part describes how pregnancy is a sensitive period for both the mother and fetus. In the second part, the focus is on antecedents of maternal prenatal risks pertaining to prenatal stress response systems and mental health. The third part then turns to elucidating how these alterations in prenatal stress physiology and mental health problems may affect infant and child outcomes. The fourth part underscores how pregnancy is also a time of heightened fetal receptivity to maternal and environmental signals, with profound implications for adaptation. This section also reviews empirical evidence of promotive and protective factors that buffer the mother and fetus from developmental and adaptational problems and covers a sample of rigorous evidence-based prenatal interventions that prevent maladaptation in the maternal-fetal dyad before babies are born. Finally, recommendations elaborate on how to further strengthen understanding of pregnancy as a period of multilevel risk and resilience, enhance comprehensive prenatal screening, and expand on prenatal interventions to promote maternal-fetal adaptation before birth.

Extracellular vesicles in spontaneous preterm birth

Feto-maternal communication helps to maintain pregnancy and contributes to parturition at term and preterm. Endocrine and immune factor are well-reported communication mediators. Recent advances in extracellular vesicle (EV) biology have introduced them as major communication channels between the mother and fetus. EVs are round structures with a lipid bilayer membrane. EVs are generally categorized based on their size and mode of biogenesis. The most commonly reported EVs are exosomes with a size range of 30-160 nm that are formed inside the intraluminal vesicles of multivesicular body. Microvesicles (MVs) are larger than > 200 nm and formed by outward budding of plasma membrane. Vesicles are released from all cells and carry various factors that reflect the physiologic state of cell at the time of their release. Analysis of vesicle provides a snapshot of origin cell. Recent studies in perinatal medicine have shown that exosomes are key communicators between feto-maternal units, and they can cross placenta. Fetal-derived exosomes released under term labor-associated conditions can cause parturition-associated changes in maternal uterine tissues. Exosomes carrying inflammatory cargo can cause preterm birth in animal models suggesting their functional role in parturition. A few reports have profiled differences between exosome cargos from term and preterm pregnancies and indicated their biomarker potential to predict high-risk pregnancy status. There are hardly any reports on MVs and their functional roles in reproduction. Herein, we review of EVs and MVs, their characteristics, function, and usefulness predicting adverse pregnancy complications such as preterm birth.

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

Preterm birth remains the leading cause of neonatal morbidity and mortality, with complex biochemical pathways requiring continued understanding and assessment. The objective of this study is to assess the associations between maternal cortisol and placental corticotropin-releasing hormone (placental CRH) concentrations with birth outcomes when stratified by placental histopathology. We conducted an analysis of 112 singleton pregnancies who received betamethasone between 23 and 34 weeks' gestation. Maternal blood and saliva were collected prior to betamethasone administration and samples assayed for plasma cortisol (pCort), salivary cortisol (sCort), and placental CRH levels. Placental findings were characterized as inflammatory, maternal vascular underperfusion (MVU), or no pathology, and compared for the outcomes of placental CRH, pCort, and sCort levels, gestational age at birth (GAB), and birthweight percentiles (BWP). Thirty-six subjects were characterized as inflammatory, 38 as MVU, and 38 without placental abnormalities. Histopathology groups differed significantly on placental CRH levels, GAB, and BWP. Post hoc tests suggested that the MVU group had higher placental CRH than the inflammatory or no pathology groups, and despite delivering earlier than the other two groups, the inflammatory group had infants with significantly higher BWP. No differences existed between groups in terms of mean plasma or sCort levels. Higher placental CRH and pCort levels were associated with earlier GAB in the overall sample, but when split by group, these associations remained significant only among the MVU group. Higher placental CRH was also associated with lower BWP in the overall sample but did not remain significant when split by group. Higher sCort was associated with lower BWP only in the MVU group. There is differentiation of placental CRH, cortisol, and birth outcomes when evaluated by placental histopathology. This highlights the importance of evaluating birth outcomes within the context of placental histopathology.

Novel pathways of inflammation in human fetal membranes associated with preterm birth and preterm pre-labor rupture of the membranes

Spontaneous preterm birth (PTB) and preterm pre-labor rupture of the membranes (pPROM) are major pregnancy complications. Although PTB and pPROM have common etiologies, they arise from distinct pathophysiologic pathways. Inflammation is a common underlying mechanism in both conditions. Balanced inflammation is required for fetoplacental growth; however, overwhelming inflammation (physiologic at term and pathologic at preterm) can lead to term and preterm parturition. A lack of effective strategies to control inflammation and reduce the risk of PTB and pPROM suggests that there are several modes of the generation of inflammation which may be dependent on the type of uterine tissue. The avascular fetal membrane (amniochorion), which provides structure, support, and protection to the intrauterine cavity, is one of the key contributors of inflammation. Localized membrane inflammation helps tissue remodeling during pregnancy. Two unique mechanisms that generate balanced inflammation are the progressive development of senescence (aging) and cyclic cellular transitions: epithelial to mesenchymal (EMT) and mesenchymal to epithelial (MET). The intrauterine build-up of oxidative stress at term or in response to risk factors (preterm) can accelerate senescence and promote a terminal state of EMT, resulting in the accumulation of inflammation. Inflammation degrades the matrix and destabilizes membrane function. Inflammatory mediators from damaged membranes are propagated via extracellular vesicles (EV) to maternal uterine tissues and transition quiescent maternal uterine tissues into an active state of labor. Membrane inflammation and its propagation are fetal signals that may promote parturition. This review summarizes the mechanisms of fetal membrane cellular senescence, transitions, and the generation of inflammation that contributes to term and preterm parturitions.

Ageing in human parturition: impetus of the gestation clock in the decidua†

Despite sharing many common features, the relationship between ageing and parturition remains poorly understood. The decidua is a specialized lining of endometrial tissue, which develops in preparation for pregnancy. The structure and location of the decidua support its role as the physical scaffold for the growing embryo and placenta, and thus, it is vital to sustain pregnancy. Approaching term, the physical support properties of the decidua are naturally weakened to permit parturition. In this review, we hypothesize that the natural weakening of decidual tissue at parturition is promoted by the ageing process. Studies of the ageing-related functional and molecular changes in the decidua at parturition are reviewed and classified using hallmarks of ageing as the framework. The potential roles of decidual mesenchymal stem/stromal cell (DMSC) ageing in labor are also discussed because, although stem cell exhaustion is also a hallmark of ageing, its role in labor is not completely understood. In addition, the potential roles of extracellular vesicles secreted by DMSCs in labor, and their parturition-related miRNAs, are reviewed to gain further insight into this research area. In summary, the literature supports the notion that the decidua ages as the pregnancy progresses, and this may facilitate parturition, suggesting that ageing is the probable impetus of the gestational clocks in the decidua. This conceptual framework was developed to provide a better understanding of the natural ageing process of the decidua during parturition as well as to encourage future studies of the importance of healthy ageing for optimal pregnancy outcomes.

Leukemia inhibitory factor induces corticotropin-releasing hormone in mouse trophoblast stem cells

Previous studies have shown that some inflammatory cytokines promote the expression of corticotropin-releasing hormone (CRH) in trophoblasts during pregnancy and that placental CRH could induce the production of adrenocorticotropic hormone (ACTH) in humans. However, whether the same is true in rodent placenta remains unclear. In this study, we examined the effect of pro-inflammatory cytokine LIF on the induction of CRH in mouse trophoblast stem cells (mTSCs). During differentiation, the CRH levels in mTSCs gradually increased. On days 3 and 5 after LIF supplementation, Crh expression in the differentiated mTSCs was significantly increased with LIF treatment than those without LIF treatment. Moreover, the CRH concentration in the culture media increased. Thereafter, we examined the contribution of the downstream pathways of LIF to CRH induction in differentiated mTSCs. The LIF-induced upregulation of CRH was attenuated by inhibition of PI3K/AKT and MAPK phosphorylation but not by inhibition of JAK/STAT3. Therefore, in mTSCs, LIF increased Crh expression through activation of the PI3K/AKT and MAPK pathways but not by the JAK/STAT3 pathway. The present study suggests that mTSC is an ideal in vitro model for studying regulation and function of placental CRH.

SKA2 gene - A novel biomarker for latent anxiety and preterm birth prediction

BACKGROUND

There is a relationship between preterm birth (PTB) and anxiety. Spindle and Kinetochore Associated Complex Subunit 2 (SKA2) gene polymorphism (NC_000017.11: g.59110368 G > A) has also been associated with the development of anxiety. The current study was designed to evaluate the relationship between SKA2 gene SNP (NC_000017.11: g.59110368 G > A) with the occurrence of anxiety and PTB which might be considered a predictive biomarker for the prediction of preterm delivery.

METHODS

SKA2 gene (SNP rs7208505) genotyping was performed in 300 women with term birth (TB) and 293 women with PTB using PCR-RFLP method and then followed by DNA sequencing. Cortisol level was analyzed with ELISA method and the presence of anxiety was detected using Spielberg Inventory.

RESULTS

The AA genotype of SKA2 gene significantly increased the risk of PTB compared to the GG genotype by 9.6 fold ([CI] 4.5-20.2, P < 0.001) according to codominant model. Also, the frequency of A allele was significantly higher in PTB group (χ2 = 20.4, df = 1, P < 0.001) in comparison with the control group that increased the risk of PTB by 1.703 fold ([CI] 1.39-2.23, P < 0.001). Women with higher cortisol level with average 343.7 ± 3 nmol/L had AA genotype, while, the concentrations of cortisol in women with AG, and GG genotypes were 244.2 ± 3.1 nmol/L and 192.6 ± 2.5 nmol/L, respectively (P < 0.001). The score of apparent and latent anxiety in women with the AA genotype was higher compared to the AG and GG genotypes and also this score in women with the AG genotype was higher than the GG genotypes (P < 0.001). The history of preterm delivery was higher in women with the AA genotype (42.1%) in comparison with the GG (14.9%) and AG (22%) genotypes (P < 0.05).

CONCLUSION

The results of the current study suggest that prognosis of women with the AA genotype are more susceptible to be spontaneous preterm birth. Therefore, the A allele of SKA2 gene (NC_000017.11:g.59110368 G > A) could be as a predictive biomarker for the risk of PTB.

Quantitative Proteomics by SWATH-MS of Maternal Plasma Exosomes Determine Pathways Associated With Term and Preterm Birth

Exosomes are membrane-bound nanovesicles that transport molecular signals between cells. This study determined changes in maternal plasma exosome proteomics contents in term and preterm births. Maternal plasma (MP) samples were collected from group 1: term not in labor (TNIL, n = 13); group 2: term in labor (TL, n = 11); group 3: preterm premature rupture of membranes (pPROM, n = 8); and group 4: preterm birth (PTB, n = 13). Exosomes isolated from plasma by differential density centrifugation followed by size exclusion chromatography were characterized by morphology (electron microscopy), quantity and size (nanoparticle tracking analysis), and markers (western blot). A quantitative, information-independent acquisition [sequential windowed acquisition of all theoretical mass spectra (SWATH-MS)] approach was used to determine the protein profile in exosomes. Ingenuity Pathway Analysis determined pathways associated with the protein profile identified in exosomes. MP exosomes were spherical, had a mean diameter of 120 nm, and were positive for exosomal proteins CD63 and TSG101 irrespective of pregnancy status. No distinct changes in exosome quantities were seen in maternal circulation across the groups. SWATH-MS identified 72 statistically significant proteins across the groups studied. Bioinformatics analysis showed the proteins within the exosomes in TNIL, TL, pPROM, and PTB target pathways mainly associated with inflammatory and metabolic signals. Exosomal data suggest that homeostatic imbalances, specifically inflammatory and endocrine signaling, might disrupt pregnancy maintenance resulting in labor-related changes both at term and preterm. Reflection of physiologic changes in exosomes is suggestive of its usefulness as biomarkers and cellular function indicators.

Cumulative cortisol exposure in the third trimester correlates with postpartum mothers' neural response to emotional interference

Prolonged stress affects the central nervous system, rendering individuals vulnerable to a wide range of mental health disorders. 76 healthy postpartum mothers were studied by means of functional magnetic resonance imaging within 6 days of childbirth. The subjects were required to perform the emotional Stroop task involving happy and anxious word-face combinations. Hair samples were collected to determine cumulative hair cortisol concentration (HCC) in the third trimester. HCC was found to be negatively correlated with the recruitment of the dorsal anterior cingulate cortex (ACC) and the midcingulate cortex (MCC). In response to the emotional interference of only anxious target faces, a negative correlation was seen between HCC and the bilateral orbitofrontal cortex, extending to the rostral ACC and the MCC. Women with lower HCC recruited brain areas relevant to emotional cognitive control, indicating that lower HCC helps preserve conflict monitoring and resolution capacities and thus benefits mental health in pregnancy.

Can Placental Corticotropin-Releasing Hormone Inform Timing of Antenatal Corticosteroid Administration?

CONTEXT

Antenatal corticosteroids are commonly administered to pregnant women at risk for delivering between 23 and 34 gestational weeks; they provide crucial benefits to fetal lung maturation and reduce risk for neonatal morbidity and mortality. Corticosteroids are maximally efficacious for lung maturation when administered within 2 to 7 days of delivery. Accurately identifying the timing of preterm delivery is thus critical to ensure that antenatal corticosteroids are administered within a week of delivery and to avoid unnecessary administration to women who will deliver at term. A plausible biomarker for predicting time of delivery is placental corticotropin-releasing hormone (pCRH).

OBJECTIVE

To assess whether pCRH concentrations predict time to delivery and specifically which women will deliver within a week of treatment.

DESIGN

pCRH concentrations were evaluated before administration of the corticosteroid betamethasone, and timing of delivery was recorded.

PARTICIPANTS

A total of 121 women with singleton pregnancies who were prescribed betamethasone.

RESULTS

Elevated pCRH concentrations were associated with a shorter time from treatment to delivery. Receiver-operating characteristic curves revealed that pCRH may improve the precision of predicting preterm delivery.

CONCLUSIONS

In the current sample, pCRH concentrations predicted the likelihood of delivering within 1 week of corticosteroid treatment. Current findings suggest that pCRH may be a diagnostic indicator of impending preterm delivery. Increasing the precision in predicting time to delivery could inform when to administer antenatal corticosteroids, thus maximizing benefits and reducing the likelihood of exposing fetuses who will be delivered at term.

Prenatal CRH: An integrating signal of fetal distress

Corticotropin-releasing hormone (CRH) is distributed throughout the brain and in peripheral sites but primarily is localized in the paraventricular nucleus of the hypothalamus. It is a "master" stress hormone that is responsible for the synthesis of proopiomelanocortin (POMC) in the anterior pituitary gland. Behaviorally active peptide hormones, including adrenocorticotropin hormone (ACTH) and B-endorphin, are liberated from POMC by enzymes to activate critical processes during stress. CRH is not detectable in the circulation even during extreme stress. However, during human pregnancy, the human placenta expresses the gene for CRH (pCRH) resulting in detectable levels in maternal plasma that increases 20- to 40-fold over the course of gestation. Placental CRH is identical to CRH of hypothalamic origin in size, structure, immunoreactivity, and bioactivity. However, unlike the negative feedback between adrenal cortisol and hypothalamic CRH, cortisol stimulates the synthesis and release of pCRH. The bidirectional release of pCRH into maternal and fetal compartments is associated with regulating the timing of delivery, remodeling the fetal nervous system, and influencing developmental trajectories. Fetal exposure to pCRH during early and late gestation is associated with unique patterns of cortical thinning in school-age children. Placental CRH is elevated in response to physical and behavioral stress and may be an integrative marker of early adversity.

Pregnancy in Women with Obesity

Pregnancy in women with obesity is an important public health problem with short- and long-term implications for maternal and child health. Obesity complicates almost all aspects of pregnancy. Given the growing prevalence of obesity in women, obstetric providers need to understand the risks associated with obesity in pregnancy and the unique aspects of management for women with obesity. Empathic and patient-centered care, along with knowledge, can optimize outcomes for women and children.

Placental pathology, corticotropin-releasing hormone, timing of parturition, and fetal growth in the pregnancy outcomes and community health study

Background: Identification of vascular pathologies in delivered placentas and their associations with biomarkers measured during pregnancy may elucidate mechanisms of adverse pregnancy outcomes and inform early detection and intervention strategies.Objectives: To examine associations of placental vascular pathology with birth size and timing of parturition, and to evaluate maternal midpregnancy serum corticotropin-releasing hormone (CRH) levels as a marker of the above associations.Study design: The pregnancy outcomes and community health (POUCH) Study enrolled women at 16-27 weeks of pregnancy from five Michigan communities. Histological assessments of delivered placentas and assays of CRH in maternal blood sampled at enrollment were performed in a subcohort of 1152 participants. Five placental vascular pathology constructs were formulated: Maternal-Vascular-Obstructive (MVO), Fetal Vascular-Obstructive (FVO), Maternal Vascular-disturbance of Integrity (MVI), Fetal Vascular-disturbance of Integrity (FVI), and Maternal Vascular-Developmental (MVD). A four-level outcome variable combined small for gestational (SGA) yes/no and delivery timing preterm/term; the non-SGA/term served as the referent group. In multinomial logistic regression models, the five vascular pathology groups were evaluated in relation to the outcome variable and effect sizes were compared before versus after exclusion of participants with high CRH (top quartile).Results: Adjusted odds ratios (aOR) for MVO among SGA/term and SGA/preterm were 4.1 (95% CI: 2.2, 7.9) and 8.8 (95% CI: 3.3, 23.5) respectively. Among SGA/preterm births, the aOR was attenuated by ∼40%, i.e. 5.4 (95% CI: 1.1, 26.2) after removing high CRH pregnancies. MVI and FVO were each associated with SGA/preterm, aOR = 3.7 (95% CI: 1.3, 10.3) and 10.5 (95% CI: 3.6, 30.8) respectively. Removal of high CRH pregnancies reduced the OR estimates by nearly half, i.e. MVI aOR = 1.9 (95% CI: 0.34, 10.9), FVO aOR = 6.0 (95% CI: 1.3, 28.6). MVI, FVI and MVD were each associated with greater odds of non-SGA/preterm, but the aORs showed little change after removing high CRH pregnancies.Conclusions: Obstructive placental vascular pathologies in maternal or fetal vessels are associated with SGA. High CRH levels coincided with a portion of pregnancies that share these complications, particularly among pregnancies that also ended prematurely.

An experimental test of the fetal programming hypothesis: Can we reduce child ontogenetic vulnerability to psychopathology by decreasing maternal depression?

Maternal depression is one of the most common prenatal complications, and prenatal maternal depression predicts many child psychopathologies. Here, we apply the fetal programming hypothesis as an organizational framework to address the possibility that fetal exposure to maternal depressive symptoms during pregnancy affects fetal development of vulnerabilities and risk mechanisms, which enhance risk for subsequent psychopathology. We consider four candidate pathways through which maternal prenatal depression may affect the propensity of offspring to develop later psychopathology across the life span: brain development, physiological stress regulation (hypothalamic-pituitary-adrenocortical axis), negative emotionality, and cognitive (effortful) control. The majority of past research has been correlational, so potential causal conclusions have been limited. We describe an ongoing experimental test of the fetal programming influence of prenatal maternal depressive symptoms using a randomized controlled trial design. In this randomized controlled trial, interpersonal psychotherapy is compared to enhanced usual care among distressed pregnant women to evaluate whether reducing prenatal maternal depressive symptoms has a salutary impact on child ontogenetic vulnerabilities and thereby reduces offspring's risk for emergence of later psychopathology.

Oxidative stress induces p38MAPK-dependent senescence in the feto-maternal interface cells

OBJECTIVE

This study tested the mechanism of the oxidative stress (OS)-induced senescence pathway at the feto-maternal interface cells.

METHODS

Primary amnion mesenchymal cells (AMCs), chorion and decidual cells isolated from the placental membranes of women at normal term (not in labor) were exposed to OS-inducing cigarette smoke extract (CSE) for 48 h. Reactive oxygen species (ROS) was measured using 2'7'-dichlorodihydrofluorescein. Western blot analysis determined phosphorylated (P) p38MAPK and p53 expression. Senescence-associated β-Galactosidase (SA-β-Gal) and matrix metallopeptidase 9 (MMP9) histochemistry were used to measure senescence and inflammation respectively. Cotreatment of cells with the antioxidant, N-acetyl cysteine (NAC), or the p38MAPK inhibitor, SB203580 (SB), verified the activation specificity.

RESULTS

CSE increased ROS production from AMCs, chorion cells, and decidual cells (P < 0.05) compared to controls. Western blot analysis determined that CSE induced p38MAPK activation (P < 0.05) and cotreatment with NAC inhibited ROS production and p38MAPK activation (P < 0.05) in all cell types. CSE did not increase p53 phosphorylation in any of the cells; however, AMCs showed constitutive P-p53 expression. CSE increased senescence in AMCs and chorion cells compared to controls (P = 0.01 and P = 0.003, respectively); however, senescence was not observed in decidual cells. Senescence was significantly reduced following cotreatment with SB and NAC (AMCs; P = 0.01 and chorion; P = 0.009). CSE increased MMP9 in all cells that was reduced by NAC.

CONCLUSION

OS induced p38MAPK activation and inflammation in all cell types that was associated with senescence in fetal cells but not in maternal cells.

Regulation of p38 mitogen-activated kinase-mediated fetal membrane senescence by statins

PROBLEM

Oxidative stress (OS)-induced, p38 mitogen-activated protein kinase (p38MAPK)-mediated chorioamniotic senescence and inflammation (senescence-associated secretory phenotype [SASP]) are associated with parturition. In response to OS-inducing risk factors, premature senescence contributes to preterm premature rupture of the membranes (pPROM) and spontaneous preterm birth (PTB). We determined the effect of simvastatin, rosuvastatin, and progesterone in downregulating p38MAPK-mediated senescence and SASP.

METHOD OF STUDY

Normal term, not-in-labor fetal membranes (n = 8) were exposed to cigarette smoke extract (CSE: OS inducer) alone or combined with simvastatin (100 and 200 ng/mL), rosuvastatin (100 and 200 ng/mL), and progesterone (10^-6  mol/L). p38MAPK expression changes were studied by Western blot, senescence was determined by senescence-associated β-Galactosidase (SA-β-Gal) staining, and multiplex analysis determined changes associated with 4 SASP markers (IL-8, IL-10, TNF-α, and GM-CSF). A pairwise comparison between groups was conducted by ANOVA.

RESULTS

Compared to untreated controls, CSE induced p38MAPK-mediated senescence and SASP. CSE cotreatment with simvastatin and rosuvastatin significantly reduced p38MAPK activation, senescence (decrease in SA-β-Gal) and SASP markers, GM-CSF, and TNF, but not IL-8, while increasing anti-inflammatory IL-10 in a dose-dependent manner. Cotreatment of CSE and progesterone had no effect on reducing p38MAPK activation, senescence, or SASP.

CONCLUSION

Both simvastatin and rosuvastatin downregulated OS-induced p38MAPK activation, senescence, and SASP, while rosuvastatin showed a pronounced effect. Progesterone did not reduce OS-induced fetal membrane senescence and SASP. Simvastatin or rosuvastatin may reduce the incidences of OS-associated PTB and pPROM by preventing premature senescence and SASP.

Amniotic Fluid Exosome Proteomic Profile Exhibits Unique Pathways of Term and Preterm Labor

Our objective was to determine the amniotic fluid-derived exosomal proteomic profile in patients who had spontaneous preterm birth (PTB) or preterm premature rupture of membranes (pPROM) compared with those who delivered at term. A cross-sectional study of a retrospective cohort was used to quantify and determine the protein content of exosomes present in amniotic fluid, in PTB or pPROM, and normal term labor (TL) or term not in labor (TNIL) pregnancies. Exosomes were isolated by differential centrifugation and quantified using nanocrystals (Qdot) coupled to CD63 and placental alkaline phosphatase (PLAP) by fluorescence nanoparticle tracking analysis. The exosomal proteomic profile was identified by liquid chromatography-tandem mass spectrometry, and a small ion library was constructed to quantify the proteomic data by Sequential Window Acquisition of All Theoretical analysis. Ingenuity Pathway Analysis determined canonical pathways and biofunctions associated with dysregulated proteins. Amniotic fluid exosomes have similar shape and quantity regardless of the conditions; however, the PLAP/CD63 ratios for TL, PTB, and pPROM were significantly higher (∼3.8-, ∼4.4-, and ∼3.5-fold, respectively) compared with TNIL. The PLAP/CD63 ratio was also significantly higher (∼1.3-fold) in PTB compared with pPROM. Biological functions primarily indicated nonspecific inflammatory response regardless of condition, but unique profiles were also identified in cases (PTB and pPROM) compared with term. Amniotic fluid exosomes provide information specific to normal and abnormal parturition. Inflammatory marker enrichment and its uniqueness in term and preterm pregnancies support the value of exosomes in determining underlying physiology associated with term and preterm parturition.

Biomechanics of the human uterus

The appropriate biomechanical function of the uterus is required for the execution of human reproduction. These functions range from aiding the transport of the embryo to the implantation site, to remodeling its tissue walls to host the placenta, to protecting the fetus during gestation, to contracting forcefully for a safe parturition and postpartum, to remodeling back to its nonpregnant condition to renew the cycle of menstruation. To serve these remarkably diverse functions, the uterus is optimally geared with evolving and contractile muscle and tissue layers that are cued by chemical, hormonal, electrical, and mechanical signals. The relationship between these highly active biological signaling mechanisms and uterine biomechanical function is not completely understood for normal reproductive processes and pathological conditions such as adenomyosis, endometriosis, infertility and preterm labor. Animal studies have illuminated the rich structural function of the uterus, particularly in pregnancy. In humans, medical imaging techniques in ultrasound and magnetic resonance have been combined with computational engineering techniques to characterize the uterus in vivo, and advanced experimental techniques have explored uterine function using ex vivo tissue samples. The collective evidence presented in this review gives an overall perspective on uterine biomechanics related to both its nonpregnant and pregnant function, highlighting open research topics in the field. Additionally, uterine disease and infertility are discussed in the context of tissue injury and repair processes and the role of computational modeling in uncovering etiologies of disease. WIREs Syst Biol Med 2017, 9:e1388. doi: 10.1002/wsbm.1388 For further resources related to this article, please visit the WIREs website.

Association among Maternal Obesity, Cervical Length, and Preterm Birth

Objective The objective of this study was to determine if mid-trimester cervical length is associated with the inverse relationship between maternal body mass index (BMI) at delivery and spontaneous preterm birth (SPTB). Materials and Methods This was a retrospective cohort of women with a singleton pregnancy without prior SPTB who underwent routine transvaginal cervical length assessment between 18 and 24 weeks. Women were categorized into four BMI groups: (1) 18.5 to 24.9, (2) 25 to 29.9, (3) 30 to 34.9, and (4) ≥ 35 kg/m2. Univariable and multivariable analyses were conducted to determine whether BMI group was associated with SPTB at < 37, 34, or 32 weeks independent of the cervical length. Results Of the 18,100 women in this analysis, 43.5% had a BMI ≥ 30. In univariable analysis, increasing BMI group was associated with longer cervical length but not with cervical length < 10th percentile. SPTB at < 37, 35, and 32 weeks was less common among women with higher BMI. In multivariable regression, a higher BMI group was associated with a lower frequency of SPTB at 37 weeks (adjusted odds ratios [aORs] of 0.64, 0.68, and 0.51), at 34 weeks (aORs of 0.53, 0.54, and 0.31) and at 32 weeks (aORs of 0.47, 0.60, and 0.27) for BMI groups 2 to 4, respectively. This association persisted even when cervical length was entered into the model as a covariate. Conclusion Women with a higher BMI group had longer mid-trimester cervical length, and correspondingly reduced SPTB. However, the decreased risk of SPTB was not associated with cervical length. The reason for the potential protective effect from prematurity is unknown and its mechanisms require further investigation.

Programmed Fetal Membrane Senescence and Exosome-Mediated Signaling: A Mechanism Associated With Timing of Human Parturition

Human parturition is an inflammatory process that involves both fetal and maternal compartments. The precise immune cell interactions have not been well delineated in human uterine tissues during parturition, but insights into human labor initiation have been informed by studies in animal models. Unfortunately, the timing of parturition relative to fetal maturation varies among viviparous species-indicative of different phylogenetic clocks and alarms-but what is clear is that important common pathways must converge to control the birth process. Herein, we hypothesize a novel signaling mechanism initiated by human fetal membrane aging and senescence-associated inflammation. Programmed events of fetal membrane aging coincide with fetal growth and organ maturation. Mechanistically, senescence involves in telomere shortening and activation of p38 mitogen-activated signaling kinase resulting in aging-associated phenotypic transition. Senescent tissues release inflammatory signals that are propagated via exosomes to cause functional changes in maternal uterine tissues. In vitro, oxidative stress causes increased release of inflammatory mediators (senescence-associated secretory phenotype and damage-associated molecular pattern markers) that can be packaged inside the exosomes. These exosomes traverse through tissues layers, reach maternal tissues to increase overall inflammatory load transitioning them from a quiescent to active state. Animal model studies have shown that fetal exosomes can travel from fetal to the maternal side. Thus, aging fetal membranes and membrane-derived exosomes cargo fetal signals to the uterus and cervix and may trigger parturition. This review highlights a novel hypothesis in human parturition research based on data from ongoing research using human fetal membrane model system.

Placental membrane aging and HMGB1 signaling associated with human parturition

Aging is associated with the onset of several diseases in various organ systems; however, different tissues may age differently, rendering some of them dysfunctional sooner than others. Placental membranes (fetal amniochorionic membranes) protect the fetus throughout pregnancy, but their longevity is limited to the duration of pregnancy. The age-associated dysfunction of these membranes is postulated to trigger parturition. Here, we investigated whether cellular senescence-the loss of cell division potential as a consequence of stress-is involved in placental membrane function at term. We show telomere reduction, p38 MAPK activation, increase in p21 expression, loss of lamin B1 loss, increase in SA-β-galactosidase , and senescence-associated secretory phenotype (SASP) gene expression in placental membranes after labor and delivery (term labor [TL]) compared to membranes prior to labor at term (term, not-in-labor [TNIL]). Exposing TNIL placental membranes to cigarette smoke extract, an oxidative stress inducer, also induced markers of cellular senescence similar to those in TL placental membranes. Bioinformatics analysis of differentially expressed SASP genes revealed HMGB1 signaling among the top pathways involved in labor. Further, we show that recombinant HMGB1 upregulates the expression of genes associated with parturition in myometrial cells. These data suggest that the natural physiologic aging of placental tissues is associated with cellular senescence and human parturition.

Feto-Maternal Trafficking of Exosomes in Murine Pregnancy Models

Timing and initiation of labor are well-orchestrated by signals communicated between the fetal and maternal compartments; however, how these signals are communicated is not completely understood. Fetal exosomes, intercellular signaling vesicles, may play a key role in the process. The objective of this study was to evaluate exosome trafficking in vivo from fetal to maternal compartments. Pregnant CD-1 mice were intra-amniotically injected on gestational day 16 and 17 with exosomes isolated from primary human amnion epithelial cells fluorescently labeled with the lipophilic dye 1,1-dioctadecyl-3,3,3,3-tetramethylindotricarbocyanine iodide (DiR). All our analyses were performed on samples collected on Day 18. After 24 h, mice were imaged using Bruker MS FX PRO In vivo Imager and tissues were collected. In vivo imaging of mouse showed fluorescence in the uterus, on the exosome-injected side whereas the uterine tissues from the uninjected side and saline and dye alone injected animals remained negative. Histological analysis of placenta showed exosome migration from the fetal to the maternal side of the placenta. Fluorescence released from exosomes was seen in maternal blood samples as well as in maternal uterus and kidneys. This study demonstrates that exosomal cargo can be carried through systemic route from the fetal to the maternal side of the uterine tissues during pregnancy, supporting the idea that fetal signals can be delivered via exosomes.

Prevention of preterm delivery: current challenges and future prospects

Preterm birth (PTB), defined as delivery at <37 weeks of gestation, is the most important cause of neonatal morbidity and mortality. Therefore, preventing PTB is one of the main goals in obstetric care. In this review, we provide an overview of the current available literature on screening for risk factors for PTB and a summary of preventive strategies in both low-risk and high-risk women with singleton or multiple gestations. Furthermore, current challenges and future prospects on PTB are discussed. For an optimal prevention of PTB, risk stratification should be based on a combination of (maternal) risk factors, obstetric history, and screening tools. Cervical length measurements can help identify women at risk. Thereafter, preventive strategies such as progesterone, pessaries, and cerclage may help prevent PTB. Effective screening and prevention of PTB vary between the different pregnancy populations. In singleton or multiple pregnancies with a short cervix, without previous PTB, a pessary or progesterone might prevent PTB. In women with a (recurrent) PTB in the past, progesterone and a cerclage may prevent recurrence. The effect of a pessary in these high-risk women is currently being studied. A strong collaboration between doctors, patients' organizations, pharmaceutical companies, and (international) governments is needed to reduce the morbidity and mortality as a result of spontaneous PTB.

Misoprostol modulates the gene expression prostaglandin E2 and oxidative stress markers in myometrial cells

Misoprostol, prostaglandin E1 analogue, used for labour induction. However, one-third of patients who have labour induced with prostaglandins do not reach vaginal delivery. The differential expression of prostaglandin receptors in myometrial cells could account for this differential response. Since delivery physiology also involves modulation of oxidative metabolism that can be potentially affected by pharmacological drugs, in the present investigation the role of misoprostol on expression of prostaglandin receptors, and oxidative markers of myometrial cells was evaluated. Samples of myometrial tissues procured from women with spontaneous (SL) and nonspontaneous (NSL) labours were cultured in vitro and exposed to different concentrations of misoprostol. Gene expression was evaluated by qRT-PCR and oxidative biomarkers were evaluated by spectrophotometric and fluorometric analysis. Cells from SL women presented greater responsiveness to misoprostol, since an upregulation of genes related to increased muscle contraction was observed. Otherwise, cells from NSL women had low responsiveness to misoprostol exposure or even a suppressive effect on the expression of these genes. Oxidative biomarkers that previously have been related to labour physiology were affected by misoprostol treatment: lipoperoxidation and protein carbonylation (PC). However, a decrease in lipoperoxidation was observed only in SL cells treated with low concentrations of misoprostol, whereas a decrease of PC occurred in all samples treated with different misoprostol concentrations. The results suggest a pharmacogenetic effect of misoprostol in labour induction involving differential regulation of EP receptor genes, as well as some minor differential modulation of oxidative metabolism in myometrial cells.

Novel concepts on pregnancy clocks and alarms: redundancy and synergy in human parturition

The signals and mechanisms that synchronize the timing of human parturition remain a mystery and a better understanding of these processes is essential to avert adverse pregnancy outcomes. Although our insights into human labor initiation have been informed by studies in animal models, the timing of parturition relative to fetal maturation varies among viviparous species, indicative of phylogenetically different clocks and alarms; but what is clear is that important common pathways must converge to control the birth process. For example, in all species, parturition involves the transition of the myometrium from a relaxed to a highly excitable state, where the muscle rhythmically and forcefully contracts, softening the cervical extracellular matrix to allow distensibility and dilatation and thus a shearing of the fetal membranes to facilitate their rupture. We review a number of theories promulgated to explain how a variety of different timing mechanisms, including fetal membrane cell senescence, circadian endocrine clocks, and inflammatory and mechanical factors, are coordinated as initiators and effectors of parturition. Many of these factors have been independently described with a focus on specific tissue compartments.In this review, we put forth the core hypothesis that fetal membrane (amnion and chorion) senescence is the initiator of a coordinated, redundant signal cascade leading to parturition. Whether modified by oxidative stress or other factors, this process constitutes a counting device, i.e. a clock, that measures maturation of the fetal organ systems and the production of hormones and other soluble mediators (including alarmins) and that promotes inflammation and orchestrates an immune cascade to propagate signals across different uterine compartments. This mechanism in turn sensitizes decidual responsiveness and eventually promotes functional progesterone withdrawal in the myometrium, leading to increased myometrial cell contraction and the triggering of parturition. Linkage of these processes allows convergence and integration of the gestational clocks and alarms, prompting a timely and safe birth. In summary, we provide a comprehensive synthesis of the mediators that contribute to the timing of human labor. Integrating these concepts will provide a better understanding of human parturition and ultimately improve pregnancy outcomes.

Amnion-Epithelial-Cell-Derived Exosomes Demonstrate Physiologic State of Cell under Oxidative Stress

At term, the signals of fetal maturity and feto-placental tissue aging prompt uterine readiness for delivery by transitioning quiescent myometrium to an active stage. It is still unclear how the signals reach the distant myometrium. Exosomes are a specific type of extracellular vesicle (EVs) that transport molecular signals between cells, and are released from a wide range of cells, including the maternal and fetal cells. In this study, we hypothesize that i) exosomes act as carriers of signals in utero-placental compartments and ii) exosomes reflect the physiologic status of the origin cells. The primary aims of this study were to determine exosomal contents in exosomes derived from primary amnion epithelial cells (AEC). We also determined the effect of oxidative stress on AEC derived exosomal cargo contents. AEC were isolated from amniotic membrane obtained from normal, term, not in labor placentae at delivery, and culture under standard conditions. Oxidative stress was induced using cigarette smoke extract for 48 hours. AEC-conditioned media were collected and exosomes isolated by differential centrifugations. Both growth conditions (normal and oxidative stress induced) produced cup shaped exosomes of around 50 nm, expressed exosomes enriched markers, such as CD9, CD63, CD81 and HSC70, embryonic stem cell marker Nanog, and contained similar amounts of cell free AEC DNA. Using confocal microscopy, the colocalization of histone (H) 3, heat shock protein (HSP) 70 and activated form of pro-senescence and term parturition associated marker p38 mitogen activated protein kinase (MAPK) (P-p38 MAPK) co-localized with exosome enrich marker CD9. HSP70 and P-p38 MAPK were significantly higher in exosomes from AEC grown under oxidative stress conditions than standard conditions (p<0.05). Finally, mass spectrometry and bioinformatics analysis identified 221 different proteins involved in immunomodulatory response and cell-to-cell communication. This study determined AEC exosome characteristics and their cargo reflected the physiologic status of the cell of origin and suggests that AEC-derived exosomal p38 MAPK plays a major role in determining the fate of pregnancy. Understanding the propagation of fetal signals and their mechanisms in normal term pregnancies can provide insights into pathologic activation of such signals associated with spontaneous preterm parturitions.

Human fetal membranes at term: Dead tissue or signalers of parturition?

Various endocrine, immune, and mechanical factors produced by feto-maternal compartments at term increase intrauterine inflammatory loads to induce labor. The role of fetal (placental) membranes (amniochorion) as providers of parturition signals has not been well investigated. Fetal membranes line the intrauterine cavity and grow with and protect the fetus. Fetal membranes exist as an entity between the mother and fetus and perform unique functions during pregnancy. Membranes undergo a telomere-dependent p38 MAPK-induced senescence and demonstrate a decline in functional and mechanical abilities at term, showing signs of aging. Fetal membrane senescence is also allied with completion of fetal maturation at term as the fetus readies for delivery, which may also indicate the end of independent life and longevity of fetal membranes as their functional role concludes. Fetal membrane senescence is accelerated at term because of oxidative stress and increased stretching. Senescent fetal membranes cells produce senescence-associated secretory phenotype (SASP-inflammation) and also release proinflammatory damage-associated molecular patterns (DAMPs), namely HMGB1 and cell-free fetal telomere fragments. In a feedback loop, SASP and DAMPs increase senescence and enhance the inflammatory load to promote labor. Membranes increase the inflammatory load to disrupt homeostatic balance to transition quiescent uterine tissues toward a labor phenotype. Therefore, along with other well-described labor-promoting signals, senescent fetal membranes may also contribute to human term parturition.

Interaction of steroid receptor coactivators and estrogen receptors in the human placenta

Female sex steroid hormones such as estrogen and progesterone have a pivotal role in maintaining pregnancy in human and animals. Especially, estrogen exerts specific effects on the cardiovascular system and angiogenesis, and thus affects significantly on placentation. Although the functions of estrogen have been emphasized during pregnancy, their signaling pathways in the placenta have not been fully understood. In this study, estrogen signaling was evaluated according to gestational age. Human placenta samples were collected and divided into early preterm (n=10), late preterm (n=18), and term (n=20) groups. First, serum estrogen concentration and corticotropin-releasing hormone (CRH) mRNA expression, which is known as gestation clock gene, were increased following gestation age in our experimental condition, as we expected. Next, the expression of estrogen receptors (ERs) and steroid receptor coactivators (SRCs) in the placenta was evaluated. ERα (ESR1) and ERβ (ESR2) were expressed highly at term period compared with early preterm. In addition, SRC family including SRC1, SRC2, and SRC3 was expressed in the human placenta, and the levels of SRC1, SRC2, and SRC3 were increased in the placenta at the late stage of gestation. The interaction of ERs with SRCs was also examined, which was significantly enhanced at term period. In the immunostaining results, it was indicated that ERs and SRCs were all dominantly expressed in syncytiotrophoblast cells. These results suggested that SRC1, SRC2, and SRC3 were expressed and interact with ERs highly at the late stage of gestation, and may amplify the signaling of estrogen in the placenta to maintain pregnancy.

Fetal exposure to placental corticotropin-releasing hormone (pCRH) programs developmental trajectories

The maternal endocrine stress system is profoundly altered during the course of human pregnancy. The human placenta expresses the genes for CRH as early as the seventh week of gestation and it is the expotential increase in placental CRH (pCRH) over the course of human gestation that is responsible for the greatest modification in the maternal stress system. The bi-directional placental release of hormones into the maternal and fetal compartments has profound influences for both. The influential Fetal Programming model predicted that early or fetal exposures to maternal signals of threat or adverse conditions have lifelong consequences for health outcomes. A basic assumption of this model was that developing organisms play a dynamic role in their own construction. Data are reviewed and new data are presented that elevated pCRH over the course of human gestation plays a fundamental role in the organization of the fetal nervous system, modifies birth phenotype (the timing of the onset of spontaneous labor and delivery), and influences developmental, temperamental and metabolic trajectories. Evidence for sex differences and conserved function across species is presented. Finally, a model is presented that proposes several pathways that pCRH can program risk for health and disease.

The idiopathic preterm delivery methylation profile in umbilical cord blood DNA

BACKGROUND

Preterm delivery is the leading cause of neonatal morbidity and mortality. Two-thirds of preterm deliveries are idiopathic. The initiating molecular mechanisms behind spontaneous preterm delivery are unclear. Umbilical cord blood DNA samples are an easy source of material to study the neonatal state at birth. DNA methylation changes can be exploited as markers to identify spontaneous preterm delivery. To identify methylation differences specific to idiopathic preterm delivery, we assessed genome-wide DNA methylation changes in 24 umbilical cord blood samples (UCB) using the 450 K Illumina methylation array. After quality control, conclusions were based on 11 term and 11 idiopathic preterm born neonates. The differentially methylated positions (DMPs) specific for preterm/term delivery, neonatal sex, use of oxytocin and mode of initiation of labor were calculated by controlling the FDR p value at 0.05.

RESULTS

The analysis identifies 1855 statistically significant DMPs between preterm and term deliveries of which 508 DMPs are also attributable to clinical variables other than preterm versus term delivery. 1347 DMPs are unique to term vs preterm delivery, of which 196 DMPs do not relate to gestational age as such. Pathway analysis indicated enrichment of genes involved in calcium signalling, myometrial contraction and relaxation pathways. The 1151 DMPs that correlate with advancing gestational age (p < 0.05) include 161 DMPs that match with two previously reported studies on UCB methylation. Additionally, 123 neonatal sex specific DMPs, 97 DMPs specific to the induction of labour and 42 DMPs specific to the mode of initiation of labor were also identified.

CONCLUSION

This study identifies 196 DMPs in UCB DNA of neonates which do not relate to gestational age or any other clinical variable recorded and are specific to idiopathic preterm delivery. Furthermore, 161 DMPs from our study overlap with previously reported studies of which a subset is also reported to be differentially methylated at 18 years of age. A DMP on MYL4, encoding myosin light chain 4, is a robust candidate for the identification of idiopathic preterm labour as it is identified by all 3 independent studies.

MTHFR (C677T) polymorphism and PR (PROGINS) mutation as genetic factors for preterm delivery, fetal death and low birth weight: A Northeast Indian population based study

Preterm delivery (PTD) is one of the most significant contributors to neonatal mortality, morbidity, and long-term adverse consequences for health; with highest prevalence reported from India. The incidence of PTD is alarmingly very high in Northeast India. The objective of the present study is to evaluate the associative role of MTHFR gene polymorphism and progesterone receptor (PR) gene mutation (PROGINS) in susceptibility to PTD, negative pregnancy outcome and low birth weights (LBW) in Northeast Indian population.

Methods

A total of 209 PTD cases {extreme preterm (< 28 weeks of gestation, n = 22), very preterm (28–32 weeks of gestation, n = 43) and moderate preterm (32–37 weeks of gestation, n = 144) and 194 term delivery cases were studied for MTHFR C677T polymorphism and PR (PROGINS) gene mutation. Statistical analysis was performed using SPSS software.

Results

Distribution of MTHFR and PR mutation was higher in PTD cases. Presence of MTHFR C677T polymorphism was significantly associated and resulted in the increased risk of PTD (p < 0.001), negative pregnancy outcome (p < 0.001) and LBW (p = 0.001); more significantly in extreme and very preterm cases. Presence of PR mutation (PROGINS) also resulted in increased risk of PTD and negative pregnancy outcome; but importantly was found to increase the risk of LBW significantly in case of very preterm (p < 0.001) and moderately preterm (p < 0.001) delivery cases.

Conclusions

Both MTHFR C677T polymorphism and PR (PROGINS) mutation are evident genetic risk factors associated with the susceptibility of PTD, negative pregnancy outcome and LBW. MTHFR C677T may be used as a prognostic marker to stratify subpopulation of pregnancy cases predisposed to PTD; thereby controlling the risks associated with PTD.

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This is the first study involving the analysis of genetic risk factors associated with preterm delivery in Northeast India.

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MTHFR C677T polymorphism and PR (PROGINS) mutation in predisposition to preterm delivery, negative pregnancy outcome and low birth weight.

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MTHFR C677T polymorphism may be used as a prognostic marker to stratify subpopulation of pregnancy cases predisposed to PTD; thereby controlling the risks associated with PTD.

Lessons from evolution: developmental plasticity in vertebrates with complex life cycles

Developmental plasticity is the property of a given genotype to produce different phenotypes in response to the environmental conditions experienced during development. Chordates have two basic modes of development, direct and indirect. Direct development (mode of humans) was derived evolutionarily from indirect development (mode of many amphibians), the major difference being the presence of a larval stage with indirect development; larvae undergo metamorphosis to the juvenile adult. In amphibians, environmental conditions experienced during the larval stage can lead to extreme plasticity in behaviour, morphology and the timing of metamorphosis and can cause variation in adult phenotypic expression (carry-over effects, or developmental programming). Hormones of the neuroendocrine stress axis play pivotal roles in mediating environmental effects on animal development. Stress hormones, produced in response to a deteriorating larval habitat, accelerate amphibian metamorphosis; in mammals, stress hormones hasten the onset of parturition and play an important role in pre-term birth caused by intra-uterine stress. While stress hormones can promote survival in a deteriorating larval or intra-uterine habitat, costs may be incurred, such as reduced growth and size at metamorphosis or birth. Furthermore, exposure to elevated stress hormones during the tadpole or foetal stage can cause permanent neurological changes, leading to altered physiology and behaviour later in life. The actions of stress hormones in animal development are evolutionarily conserved, and therefore amphibians can serve as important model organisms for research on the mechanisms of developmental plasticity.

Progesterone to prevent spontaneous preterm birth

Preterm birth is the leading cause of perinatal morbidity and mortality worldwide, and its prevention is an important healthcare priority. Preterm parturition is one of the 'great obstetrical syndromes' and is caused by multiple etiologies. One of the mechanisms of disease is the untimely decline in progesterone action, which can present as a clinically silent sonographic short cervix in the midtrimester. The detection of a short cervix in the midtrimester is a powerful risk factor for preterm delivery. Vaginal progesterone can reduce the rate of preterm delivery by 45% and the rate of neonatal morbidity (admission to the neonatal intensive care unit, respiratory distress syndrome, need for mechanical ventilation, etc.). To prevent one case of spontaneous preterm birth <33 weeks of gestation, 11 patients with a short cervix would need to be treated (based on an individual patient meta-analysis). Vaginal progesterone reduces the rate of spontaneous preterm birth in women with a short cervix, both with and without a prior history of preterm birth. In patients with a prior history of preterm birth, vaginal progesterone is as effective as cervical cerclage to prevent preterm delivery. 17α-Hydroxyprogesterone caproate has not been shown to be effective in reducing the rate of spontaneous preterm birth in women with a short cervix.

New insights into the role of perinatal HPA-axis dysregulation in postpartum depression

Postpartum depression affects 10-20% of women following birth and exerts persisting adverse consequences on both mother and child. An incomplete understanding of its etiology constitutes a barrier to early identification and treatment. It is likely that prenatal hormone trajectories represent both markers of risk and also causal factors in the development of postpartum depression. During pregnancy the maternal hypothalamic-pituitary-adrenal axis undergoes dramatic alterations, due in large part, to the introduction of the placenta, a transient endocrine organ of fetal origin. We suggest that prenatal placental and hypothalamic-pituitary-adrenal axis dysregulation is predictive of risk for postpartum depression. In this model the positive feedback loop involving the systems regulating the products of the HPA axis results in higher prenatal levels of cortisol and placental corticotropin-releasing hormone. Greater elevations in placental corticotropin-releasing hormone are related to a disturbance in the sensitivity of the anterior pituitary to cortisol and also perhaps to decreased central corticotropin-releasing hormone secretion. Secondary or tertiary adrenal insufficiencies of a more extreme nature, which emerge during the prenatal period, may be predictive of an extended or more pronounced postpartum hypothalamic-pituitary-adrenal refractory period, which in turn represents a risk factor for development of postpartum depression. In addition to reviewing the relevant existing literature, new data are presented in support of this model which link elevated placental corticotropin-releasing hormone with low levels of ACTH at 3-months postpartum. Future research will further elucidate the role of hypothalamic-pituitary-adrenal axis dysregulation in postpartum depression and also whether prenatal placental and hypothalamic-pituitary-adrenal profiles might prove useful in the early identification of mothers at risk for postpartum mood dysregulation.

Proximity of term labor deepens the fall of Doppler impedance in the fetal cerebral arteries

OBJECTIVE

To determine the existence of Doppler changes in the fetal vertebral, middle cerebral and umbilical arteries prior to term labor.

METHODS

Five hundred and twenty eight Doppler examinations of the vertebral (VA), middle cerebral (MCA) and umbilical (UA) arteries resistance indices (RI) were performed between 37 and 41 weeks gestation. For each artery, values were converted into multiples of the median (MoM) and were divided into four groups according to the interval to labor and compared using Kruskal-Wallis tests. Subsequently, values were plotted in scattergrams and linear regressions and 95% confidence intervals were calculated. Finally, using multivariate analysis and model averaging, the importance and interrelationship of Doppler measurements in the explanation of the interval to labor was evaluated.

RESULTS

Univariate and multivariate analysis confirmed that, independently of gestational age, fetuses examined close to labor presented more intense Doppler changes in the cerebral arteries with a significant reduction of the VA RI and MCA RI. This reduction was larger in the MCA. No significant changes were detected in the UA.

CONCLUSION

Before the onset of term labor, the fetal cerebral flow presents an additional reduction of impedance, which is more intense in the MCA system.

Can we predict delivery date with obstetric ultrasound?

OBJECTIVE

The long-term prediction of delivery date with obstetric ultrasound.

METHOD

The cervical length (CL) and the fetal vertebral, middle cerebral and umbilical resistance indices were measured in 317 pregnancies between 30 and 37 weeks. Subsequently, multivariate analysis was applied to calculate the best model for the prediction of delivery date.

RESULTS

The best model included the examinations of the CL and the middle cerebral artery resistance index. In comparison with estimated delivery date (EDD) based on the last menstrual period, a small improvement was detected, particularly in earlier deliveries, however 34% of predictions still had an error of more than 5 days.

CONCLUSIONS

Long-term sonographic prediction of delivery date depends mainly on the CL and improves the prediction of the EDD. However, it is still too inaccurate for clinical use.

Cyclic stretch augments production of neutrophil chemokines and matrix metalloproteinases-1 (MMP-1) from human decidual cells, and the production was reduced by progesterone

PROBLEM

The purpose of this study was to evaluate the impact of mechanical stretch caused by uterine contraction and progesterone (P₄) on decidual cells (DC), neutrophil chemokines, and MMP-1 expression.

METHOD OF STUDY

DC were cultured, and cyclic stretch was applied using a computer-operated cell stretch system. Interleukin (IL)-8, growth-regulated oncogene (GRO) α, matrix metalloproteinase (MMP)-1, and mRNA and/or protein expression/activity was measured using RT-PCR and ELISA. Neutrophil chemotactic activity in conditioned media was evaluated using migration assays. The effect of P₄ was also studied.

RESULTS

Cyclic mechanical stretch increased IL-8, GROα, mRNA and protein, and MMP-1 production and activity level. Supernatant from stretched cells induced neutrophil chemotactic activity significantly. P₄ suppressed the effect of stretch.

CONCLUSION

The current study demonstrates that cyclic mechanical stretch stimulates the production of neutrophil chemokines and MMP-1 from human decidual cells, and the production was reduced by progesterone. These findings suggest that decidual cells are responding to mechanical and endocrine signals and induce biochemical factors and thereby contribute to the regulation of human labor.

Maternal serum progesterone, estradiol and estriol levels in successful dinoprostone-induced labor

Hormone-mediated quiescence involves the maintenance of a decreased inflammatory responsiveness. However, no study has investigated whether labor induction with prostanoids is associated with changes in the levels of maternal serum hormones. The objective of this study was to determine whether labor induction with dinoprostone is associated with changes in maternal serum progesterone, estradiol, and estriol levels. Blood samples were obtained from 81 pregnant women at term. Sixteen patients had vaginal birth after spontaneous labor, 12 required cesarean section after spontaneous labor and 16 underwent elective cesarean. Thirty-seven patients had labor induction with dinoprostone. Eligible patients received a vaginal insert of dinoprostone (10 mg) and were followed until delivery. Serum progesterone (P4), estradiol (E2) and estriol (E3) levels and changes in P4/E2, P4/E3 and E3/E2 ratios were monitored from admission to immediately before birth, and the association of these measures with the resulting clinical classification outcome (route of delivery and induction responsiveness) was assessed. Progesterone levels decreased from admission to birth in patients who underwent successful labor induction with dinoprostone [vaginal and cesarean birth after induced labor: 23% (P < 0.001) and 18% (P < 0.025) decrease, respectively], but not in those whose induction failed (6.4% decrease, P > 0.05). Estriol and estradiol levels, P4/E2, P4/E3 and E3/E2 ratios did not differ between groups. Successful dinoprostone-induced labor was associated with reduced maternal progesterone levels from induction to birth. While a causal relationship between progesterone decrease and effective dinoprostone-induced labor cannot be established, it is tempting to propose that dinoprostone may contribute to progesterone withdrawal and favor labor induction in humans.