Histological chorioamnionitis at term according to labor onset: a prospective controlled study

The role of neutrophils and neutrophil extracellular traps (NETs) in stages, outcomes and pregnancy complications

Neutrophils are the main components of innate immunity to eliminate infectious pathogens. Neutrophils play a role in several stages of the reproductive cycle, and their presence in the female reproductive system is highly regulated, so their function may change during pregnancy. Emerging evidence suggests that neutrophils are important at all stages of pregnancy, from implantation, placentation, and connective tissue regeneration to birth, as well as birth itself. Neutrophil extracellular traps (NETs) are defined as extracellular strands of unfolded DNA together with histone complexes and neutrophil granule proteins. NET formation is a new mechanism of these cells for their defense function. These strands containing DNA and antimicrobial peptides were initially recognized as one of the defense mechanisms of neutrophils, but later it was explained that they are involved in a variety of non-infectious diseases. Since the source of inflammation and tissue damage is the irregular activity of neutrophils, it is not surprising that NETosis are associated with a number of inflammatory conditions and diseases. The overexpression of NET components or non-principled NET clearance is associated with the risk of production and activation of autoantibodies, which results in participation in autoinflammatory and autoimmune disorders (SLE, RA), fibrosis, sepsis and other disorders such as vascular diseases, for example, thrombosis and atherosclerosis. Recent published articles have shown the role of neutrophils and extracellular traps (NETs) in pregnancy, childbirth and pregnancy-related diseases. The aim of this study was to identify and investigate the role of neutrophils and neutrophil extracellular traps (NETs) in the stages of pregnancy, as well as the complications caused by these cells.

Placental pathology and neonatal morbidity: exploring the impact of gestational age at birth

AIM

To evaluate placental pathology in term and post-term births, investigate differences in clinical characteristics, and assess the risk of adverse neonatal outcome.

METHODS

This prospective observational study included 315 singleton births with gestational age (GA) > 36 weeks + 6 days meeting the local criteria for referral to placental histopathologic examination. We applied the Amsterdam criteria to classify the placentas. Births were categorized according to GA; early-term (37 weeks + 0 days to 38 weeks + 6 days), term (39 weeks + 0 days to 40 weeks + 6 days), late-term (41 weeks + 0 days to 41 weeks + 6 days), and post-term births (≥ 42 weeks + 0 days). The groups were compared regarding placental pathology findings and clinical characteristics. Adverse neonatal outcomes were defined as 5-minute Apgar score < 7, umbilical cord artery pH < 7.0, admission to the neonatal intensive care unit or intrauterine death. A composite adverse outcome included one or more adverse outcomes. The associations between placental pathology, adverse neonatal outcomes, maternal and pregnancy characteristics were evaluated by logistic regression analysis.

RESULTS

Late-term and post-term births exhibited significantly higher rates of histologic chorioamnionitis (HCA), fetal inflammatory response, clinical chorioamnionitis (CCA) and transfer to neonatal intensive care unit (NICU) compared to early-term and term births. HCA and maternal smoking in pregnancy were associated with adverse outcomes in an adjusted analysis. Nulliparity, CCA, emergency section and increasing GA were all significantly associated with HCA.

CONCLUSIONS

HCA was more prevalent in late and post-term births and was the only factor, along with maternal smoking, that was associated with adverse neonatal outcomes. Since nulliparity, CCA and GA beyond term are associated with HCA, this should alert the clinician and elicit continuous intrapartum monitoring for timely intervention.

Innate and Adaptive Immune Systems in Physiological and Pathological Pregnancy

The dynamic immunological changes occurring throughout pregnancy are well-orchestrated and important for the success of the pregnancy. One of the key immune adaptations is the maternal immune tolerance towards the semi-allogeneic fetus. In this review, we provide a comprehensive overview of what is known about the innate and adaptive immunological changes in pregnancy and the role(s) of specific immune cells during physiological and pathological pregnancy. Alongside this, we provided details of remaining questions and challenges, as well as future perspectives for this growing field of research. Understanding the immunological changes that occur can inform potential strategies on treatments for the optimal health of the neonate and pregnant individual both during and after pregnancy.

Retrospective study of intrapartum fever in term pregnancies and adverse obstetric and neonatal outcomes

Background

Intrapartum fever is a well-known predisposing factor for severe perinatal outcomes. Herein, we explored the intrapartum features, obstetric outcomes, and neonatal outcomes in relation to the extent of intrapartum fever via three group analyses.

Methods

A retrospective cohort analysis consisting of 575 term, singleton live births in one medical center from January 1st to December 31st, 2020 was carried out. Parturients who had experienced a maximal intrapartum fever of <38.0 °C were compared with two sub-groups of parturients who had experienced respective maximal fevers of 38.0-38.9 °C and ≥39.0 °C. We computed the adjusted risks for adverse perinatal outcomes via multiple logistic regression models to control for confounders.

Results

There were statistically remarkable differences among the three groups in 13 items including body mass index, epidural, and WBC before delivery (p < 0.05). In contrast with intrapartum fevers of 37.5-37.9 °C, intrapartum fevers of 38.0-38.9 °C were linked to an elevated risk of neonatal sepsis and neonatal intensive care unit admission with an odds ratio (OR) of 4.28 (95% CI 2.162-8.479) and 1.73 (95% CI 1.125-2.666), nonetheless, the relationship was remarkably higher for intrapartum fever ≥39.0 °C, with an OR of 6.40 (95% CI 2.450-16.725) and 2.23 (95% CI 1.021-4.854). Additionally, intrapartum fevers of 38.0-38.9 °C and ≥39.0 °C were related to remarkably higher risk for operative deliveries (OR 2.24, 95% CI 1.373-3.648; OR 3.59, 95% CI 1.398-9.226; respectively) and histological chorioamnionitis (OR 3.77, 95% CI 2.261-6.271; OR 19.24, 95% CI 7.385-50.111, respectively).

Conclusions

Intrapartum fever is an important indicator of adverse perinatal outcomes. The higher the temperature, the higher risk of histological chorioamnionitis, as well as the risk of neonatal sepsis and neonatal intensive care unit admission.

Placental lesions and differential expression of pro-and anti-angiogenic growth mediators and oxidative DNA damage marker in placentae of Ghanaian suboptimal and optimal health status pregnant women who later developed preeclampsia

Background

Angiogenic growth mediators (AGMs) and oxidative stress (OS) both play essential roles in normal placental vascular development and as such, placental alterations in these factors contribute to pre-eclampsia (PE). Suboptimal health status (SHS), an intermediate between health and disease, has been associated with imbalanced AGMs and OS biomarkers. Thus, SHS pregnant women may be at increased risk of developing PE and may present abnormal placental alteration and expression of AGMs and OS compared to optimal health status (OHS) pregnant women. We examined the histopathological morphology, immunohistochemical expression of AGMs antibodies and oxidative DNA damage marker in the placentae of SHS and OHS pregnant women who developed early-onset PE (EO-PE) and late-onset (LO-PE) compared to normotensive pregnancy (NTN-P).

Methods

This nested case-control study recruited 593 singleton normotensive pregnant women at baseline (10–20 weeks gestation) from the Ghanaian Suboptimal Health Status Cohort Study (GHOACS) undertaken at the Komfo Anokye Teaching Hospital, Ghana. Socio-demographic, clinical and obstetrics data were collected, and a validated SHS questionnaire-25 (SHSQ-25) was used in classifying participants into SHS (n = 297) and OHS (n = 296). Participants were followed until the time of PE diagnosis and delivery (32–42 weeks gestation). Blood samples were collected at the two-time points and were assayed for AGMs; soluble fms-like tyrosine kinase-1 (sFlt-1), placental growth factor (PIGF), vascular endothelial growth factor-A (VEGF-A), and soluble endoglin (sEng), and OS biomarkers; 8-hydroxydeoxyguanosine (8-OHdG), 8-epiprostaglandinF2-alpha (8- epi-PGF2α) and total antioxidant capacity (TAC) using ELISA. Placental samples were collected for histopathological and immunohistochemical analysis.

Results

Of the 593 pregnant women, 498 comprising 248 SHS and 250 OHS women returned for delivery and were included in the final analysis. Of the 248 SHS women, 56, 97 and 95 developed EO-PE, LO-PE and NTN-P, respectively, whereas 14, 30 and 206 of the 250 OHS mothers developed EO-PE, LO-PE and NTN-P, respectively. At baseline, SHS_NTN pregnant women had a significant imbalance in AGMs and OS biomarkers compared to OHS_NTN pregnant women (p<0.0001). At the time of PE diagnosis, SHS_NTN-P women who developed EO-PE, LO-PE, and NTN-P had lower serum levels of P1GF, VEGF-A and TAC and correspondingly higher levels of sEng, sFlt-1, 8-epiPGF2α, and 8-OHdG than OHS-NTN-P women who developed EO-PE and LO-PE, NTN-P (p<0.0001). A reduced placental size, increased foetal/placental weight ratio, and a significantly higher proportion of fibrinoid necrosis, infarction, villous fibrin, syncytial knots, calcification, chorangiosis, tunica media/vascular wall hypertrophy and chorioamnionitis was associated with the SHS group who developed PE (EO-PE>LO-PE) more than OHS groups who developed PE (EO-PE>LO-PE) when all were compared to NTN-P (p<0.0001). The intensity of antibody expression of PIGF and VEGF-A were significantly reduced, whereas Flt-1, Eng and 8-OHdG were significantly increased in placentae from SHS-pregnant women who developed EO-PE>LO-PE more than OHS- pregnant women who developed EO-PE>LO-PE when all were compared to NTN-P (p<0.0001).

Conclusion

Increased lesions, oxidative DNA damage, and imbalanced expression between pro-and anti-AGMs are associated more with SHS-embodied PE placentae rather than OHS-embodied PE subtypes, thus potentially allowing differential evaluation of PE.

Latent class analysis of placental histopathology: a novel approach to classifying early and late preterm births

BACKGROUND

Neonatal morbidity attributable to prematurity predominantly occurs among early preterm births (<32 weeks) rather than late preterm births (32 to <37 weeks). Methods to distinguish early and late preterm births are lacking given the heterogeneity in pathophysiology and risk factors, including maternal obesity. Although preterm births are often characterized by clinical presentation (spontaneous or clinically indicated), classifying deliveries by placental features detected on histopathology reports may help identify subgroups of preterm births with similar etiology and risk factors. Latent class analysis is an empirical approach to characterize preterm births on the basis of observed combinations of placental features.

OBJECTIVE

To identify histopathologic markers that can distinguish early (<32 weeks) and late preterm births (32 to <37 weeks) that are also associated with maternal obesity and neonatal outcomes.

STUDY DESIGN

Women with a singleton preterm birth at University of Pittsburgh Medical Center Magee-Womens Hospital (Pittsburgh, PA) from 2008 to 2012 and a placental evaluation (89% of preterm births) were stratified into early (n=900, 61% spontaneous) and late preterm births (n=3362, 57% spontaneous). Prepregnancy body mass index was self-reported at first prenatal visit and 16 abstracted placental features were analyzed. Placental subgroups (ie, latent classes) of early and late preterm births were determined separately by latent class analysis of placental features. The optimal number of latent classes was selected by comparing fit statistics. The probability of latent class membership across prepregnancy body mass indexes was estimated in early preterm births and in late preterm births by an extension of multinomial regression called pseudo-class regression, adjusting for race, smoking, education, and parity. The frequencies of severe neonatal morbidity (composite outcome: respiratory distress, bronchopulmonary dysplasia, intraventricular hemorrhage, necrotizing enterocolitis, periventricular leukomalacia, patent ductus arteriosus, and retinopathy of prematurity), small-for-gestational-age, and length of neonatal intensive care unit stay were compared across latent classes by chi-square and Kruskal-Wallis tests.

RESULTS

Early preterm births were grouped into 4 latent classes based on placental histopathologic features: acute inflammation (38% of cases), maternal vascular malperfusion with inflammation (29%), maternal vascular malperfusion (25%), and fetal vascular thrombosis with hemorrhage (8%). As body mass index increased from 20 to 50kg/m², the probability of maternal vascular malperfusion and fetal vascular thrombosis with hemorrhage increased, whereas the probability of maternal vascular malperfusion with inflammation decreased. There was minimal change in the probability of acute inflammation with increasing body mass index. Late preterm births also had 4 latent classes: maternal vascular malperfusion (22%), acute inflammation (12%), fetal vascular thrombosis with hemorrhage (9%), and low-risk pathology (58%). Body mass index was not associated with major changes in likelihood of the latent classes in late preterm births. Associations between body mass index and likelihood of the latent classes were not modified by type of delivery (spontaneous or indicated) in early or late preterm births. Maternal malperfusion and fetal vascular thrombosis with hemorrhage were associated with greater neonatal morbidity than the other latent classes in early and late preterm births.

CONCLUSION

Obesity may predispose women to early but not late preterm birth through placental vascular impairment. Latent class analysis of placental histopathologic data provides an evidence-based approach to group preterm births with shared underlying etiology and risk factors.

Adverse Maternal and Neonatal Outcomes in Women With Elevated Intrapartum Temperature Complicated by Histological Chorioamnionitis at Term: A Propensity-Score Matched Study

Background: Elevated intrapartum temperature has been widely proven to be associated with adverse clinical outcomes in both mothers and neonates. Histological chorioamnionitis (HCA), the inflammation of chorion and amniotic membranes, is commonly observed in those with elevated intrapartum temperature. Thus, we aimed to explore whether the combination of HCA would further affect the pregnancy outcomes in those with intrapartum temperature ≥ 37.5°C. Methods: This retrospective cohort study was conducted at the International Peace Maternity and Child Health Hospital (IPMCH), including all full-term women with intrapartum temperature ≥ 37.5°C from Jan 2017 to Jan 2019. Patients were divided in to HCA group or control group according to placental pathology results, and we used 1:1 propensity score matching (PSM) to reduce the effects of potential confounding factors between the two groups. Univariate and multivariable logistic regression were used to identify the association between HCA and different adverse maternal and neonatal outcomes. Results: We formed a propensity-score matched cohort containing 464 women in each group. Higher positive rate of mycoplasma (14.01% vs. 7.33%, p = 0.001) was found in the vaginal secretion culture of women in the HCA group. After adjusting for various baseline clinical characteristics, women with HCA were more likely to end their delivery by cesarean section (AOR = 1.55, 95% CI: 1.05-2.28), and puerperal morbidity (AOR = 2.77, 95% CI: 1.44-5.33) as well as prolonged hospitalization (AOR = 1.56, 95% CI: 1.12-2.17) were more likely to be observed in the HCA group. The existence of HCA might also be associated with neonatal sepsis (AOR = 2.83, 95% CI: 1.14-7.04) and NICU admission (AOR = 1.40, 95% CI: 1.04-1.87) in newborns. In the study on the impact of different stages of HCA, we found that both maternal and neonatal outcomes would not be affected by mild HCA (stage I), while HCA of stage III was associated with increased need for neonatal respiratory support and elevated likelihood of prolonged hospitalization in neonates. Conclusions: Elevated intrapartum temperature complicated by HCA might be related to the elevated occurrence of several adverse maternal and neonatal outcomes, except those with HCA of stage I. Advanced HCA stage correlated with a worse prognosis.

Histologic chorioamnionitis concomitant placental abruption and its effects on pregnancy outcome

INTRODUCTION

Two possible causative pathways have been suggested to participate in the development of placental abruption (PA), an acute inflammatory pathway and placental vascular derived, a chronic pathway. We aimed to study the impact of the inflammatory pathway on maternal and neonatal outcome.

METHODS

The computerized medical files and placental reports of all pregnancies diagnosed with PA, between 11/2008-1/2019, at 24-42 weeks, were reviewed. Placental lesions were classified according to "Amsterdam" criteria into maternal and fetal vascular malperfusion lesions, acute inflammatory responses and chronic villitis. Composite neonatal morbidity included ≥1 of the following: seizures, intra-ventricular hemorrhage (IVH), hypoxic-ischemic encephalopathy, periventricular leukomalacia (PVL), blood transfusion, necrotizing enterocolitis (NEC), neonatal sepsis, respiratory distress syndrome, or neonatal death. Maternal and neonatal outcome were compared between PA with and without histologic chorioamnionitis (HC).

RESULTS

As compared to the PA without HC group (n = 267), the PA with HC group (n = 77) was characterized by lower gestational age (GA) at delivery (32.9 ± 5.5 vs. 35.6 ± 4.1 weeks, p < 0.001), higher rates of oligohydramnios (p < 0.001), bloody amniotic fluid at labor (p < 0.001), maternal postpartum fever (p < 0.001), longer maternal hospitalization (<0.001), and increased composite adverse neonatal morbidity (41.6% vs. 22.8%, p = 0.002). By multivariate analysis, GA and HC were found to be independently associated with adverse neonatal outcome, aOR 0.63 95% CI 0.43-0.78, p < 0.001, and aOR1.12, 95% CI 1.02-3.87, p = 0.04, respectively.

DISCUSSION

The involvement of the inflammatory causative pathway in the development of placental abruption, is associated with increased maternal and neonatal morbidity.

Neutrophils in preterm birth: Friend or foe?

Preterm birth is a serious global health problem that affects 5-18% of pregnancies worldwide. In addition to being the major cause of neonatal mortality and morbidity, preterm birth is associated with short term and long term complications in the offspring. Despite this, the causes and pathogenesis of preterm birth remain unclear. Neutrophils are innate immune cells that infiltrate the maternal-fetal interface during normal parturition and their accumulation is dramatically increased during preterm birth, especially in the presence of an infection. Indeed, a defining feature of chorioamnionitis (inflammation of the chorioamnionic fetal membranes) that is associated with more than 40% of preterm births, is neutrophil accumulation. While these cells may play an important role during normal term parturition as well as preterm birth, their functions at the maternal-fetal interface are unclear. This review will provide a broad overview of the relevant studies to enable a better understanding of the roles of neutrophils during normal parturition and preterm birth.