Use of artificial intelligence in obstetric and gynaecological diagnostics: a protocol for a systematic review and meta-analysis.

INTRODUCTION: Emerging developments in applications of artificial intelligence (AI) in healthcare offer the opportunity to improve diagnostic capabilities in obstetrics and gynaecology (O&G), ensuring early detection of pathology, optimal management and improving survival. Consensus on a robust AI healthcare framework is crucial for standardising protocols that promote data privacy and transparency, minimise bias, and ensure patient safety. Here, we describe the study protocol for a systematic review and meta-analysis to evaluate current applications of AI in O&G diagnostics with consideration of reporting standards used and their ethical implications. This protocol is written following the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) 2015 checklist. METHODS AND ANALYSIS: The study objective is to explore the current application of AI in O&G diagnostics and assess the reporting standards used in these studies. Electronic bibliographic databases MEDLINE, EMBASE and Cochrane will be searched. Study selection, data extraction and subsequent narrative synthesis and meta-analyses will be carried out following the PRISMA-P guidelines. Included papers will be English-language full-text articles from May 2015 to March 2024, which provide original data, as AI has been redefined in recent literature. Papers must use AI as the predictive method, focusing on improving O&G diagnostic outcomes.We will evaluate the reporting standards including the risk of bias, lack of transparency and consider the ethical implications and potential harm to patients. Outcome measures will involve assessing the included studies against gold-standard criteria for robustness of model development (Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis, model predictive performance, model risk of bias and applicability (Prediction model Risk Of Bias Assessment Tool and study reporting (Consolidated Standards of Reporting Trials-AI) guidance. ETHICS AND DISSEMINATION: Ethical approval is not required for this systematic review. Findings will be shared through peer-reviewed publications. There will be no patient or public involvement in this study. PROSPERO REGISTRATION NUMBER: CRD42022357024 .

Antimicrobial stewardship and targeted therapies in the changing landscape of maternal sepsis.

Pregnant and postnatal women are a high-risk population particularly prone to rapid progression to sepsis with significant morbidity and mortality worldwide. Moreover, severe maternal infections can have a serious detrimental impact on neonates with almost 1 million neonatal deaths annually attributed to maternal infection or sepsis. In this review we discuss the susceptibility of pregnant women and their specific physiological and immunological adaptations that contribute to their vulnerability to sepsis, the implications for the neonate, as well as the issues with antimicrobial stewardship and the challenges this poses when attempting to reach a balance between clinical care and urgent treatment. Finally, we review advancements in the development of pregnancy-specific diagnostic and therapeutic approaches and how these can be used to optimize the care of pregnant women and neonates.

Cardiogenic shock in pregnancy.

Cardiac disease complicates 1%-4% of pregnancies globally, with a predominance in low and middle-income countries (LMICs). Increasing maternal age, rates of obesity, cardiovascular comorbidities, pre-eclampsia and gestational diabetes all contribute to acquired cardiovascular disease in pregnancy. Additionally, improved survival in congenital heart disease (CHD) has led to increasing numbers of women with CHD undergoing pregnancy. Implementation of individualised care plans formulated through pre-conception counselling and based on national and international guidance have contributed to improved clinical outcomes. However, there remains a significant proportion of women of reproductive age with no apparent comorbidities or risk factors that develop heart disease during pregnancy, with no indication for pre-conception counselling. The most extreme manifestation of cardiac disease is cardiogenic shock (CS), where the primary cardiac pathology results in inadequate cardiac output and hypoperfusion, and is associated with significant mortality and morbidity. Key to management is early recognition, intervention to treat any potentially reversible underlying pathology and supportive measures, up to and including mechanical circulatory support (MCS). In this narrative review we discuss recent developments in the classification of CS, and how these may be adapted to improve outcomes of pregnant women with, or at risk of developing, this potentially lethal condition.

Efficacy of pharmacological and mechanical cervical priming methods for induction of labour and their applicability for outpatient management: A systematic review of randomised controlled trials.

BACKGROUND: A systematic review to determine the efficacy and safety of prostaglandins (PG) and Foley catheter (FC) for cervical priming in the outpatient setting. Various methods are available to achieve cervical ripening prior to induction of labour (IOL). In this systematic review, we will report the literature to date, and investigate the efficacy and safety of using the Foley catheter balloon or prostaglandins for cervical ripening, comparing both methods with each other, and discuss the implications of these findings for midwifery led units. METHODS: English peer-reviewed journals were systematically searched in the databases PubMed, MEDLINE, EMCARE, EMBASE and CINAHL, for studies investigating cervical ripening using the FC or PGs. Additional randomised controlled trials (RCTs) and non-RCTs were identified by a manual search. Search terms included: cervix dilatation effacement, cervix ripening, outpatient, ambulatory care, obstetric patients, pharmacological preparations, and Foley catheter. Only RCTs of FC versus PG or either intervention versus placebo or intervention in the in-patient Vs. outpatient setting were included. 15 RCTs were included. RESULTS: The results of this review show that both FC and PG analogues are equally effective cervical ripening agents. When compared to FC, PGs lead to a reduced requirement for oxytocin augmentation and a shorter intervention to delivery interval. However, PG use is also associated with an increased risk of hyperstimulation, cardiotocographic monitoring abnormalities and negative neonatal outcomes. CONCLUSIONS: FC cervical ripening is an effective method of outpatient cervical priming, which is safe, acceptable, and cost-effective and thus has a potential role in both resource-rich and resource-poor countries. With appropriate dosing, some PG analogues also appear to offer similar outcomes.

Multigenerational diabetes mellitus.

Gestational diabetes (GDM) changes the maternal metabolic and uterine environment, thus increasing the risk of short- and long-term adverse outcomes for both mother and child. Children of mothers who have GDM during their pregnancy are more likely to develop Type 2 Diabetes (T2D), early-onset cardiovascular disease and GDM when they themselves become pregnant, perpetuating a multigenerational increased risk of metabolic disease. The negative effect of GDM is exacerbated by maternal obesity, which induces a greater derangement of fetal adipogenesis and growth. Multiple factors, including genetic, epigenetic and metabolic, which interact with lifestyle factors and the environment, are likely to contribute to the development of GDM. Genetic factors are particularly important, with 30% of women with GDM having at least one parent with T2D. Fetal epigenetic modifications occur in response to maternal GDM, and may mediate both multi- and transgenerational risk. Changes to the maternal metabolome in GDM are primarily related to fatty acid oxidation, inflammation and insulin resistance. These might be effective early biomarkers allowing the identification of women at risk of GDM prior to the development of hyperglycaemia. The impact of the intra-uterine environment on the developing fetus, "developmental programming", has a multisystem effect, but its influence on adipogenesis is particularly important as it will determine baseline insulin sensitivity, and the response to future metabolic challenges. Identifying the critical window of metabolic development and developing effective interventions are key to our ability to improve population metabolic health.

Simulation training for obstetric emergencies in low- and lower-middle income countries: A systematic review.

BACKGROUND: This review aims to systematically evaluate the currently available evidence investigating the effectiveness of simulation-based training (SBT) in emergency obstetrics care (EmOC) in Low- and Lower-Middle Income Countries (LMIC). Furthermore, based on the challenges identified we aim to provide a series of recommendations and a knowledge base for future research in the field. METHODS: A systematic database search was conducted of original articles that explored the use of simulation-based training for EmOC in LMIC in EMBASE, MEDLINE, Cochrane database and Google Scholar, from inception to January 2022. RESULTS: The literature search identified 1,957 articles of which a total of 15 studies were included in this review, featuring 8,900 healthcare professionals from 18 countries. The SBT programmes varied in the reviewed studies. The most common training programme consisted of the PRONTO programme implemented by four studies, comprising of 970 participants across four different countries. In general, programmes consisted of lectures, workshops and simulations of emergency obstetric scenarios followed by a debrief of participants. There were thirteen studies, comprising of 8,332 participants, which tested for improvements in clinical knowledge in post-partum haemorrhage, neonatal resuscitation, pre-eclampsia, shoulder dystocia and sepsis. All the included studies reported improvements in clinical knowledge following the simulation of scenarios. Changes in teamwork, improvement in leadership and in communication skills were also widely reported. CONCLUSION: The use of SBT programmes is not only sustainable, feasible and acceptable in LMIC, but could also improve clinical knowledge, communication, and teamwork among healthcare providers, thus directly addressing the UN Sustainable Development Goals.

Number and function of uterine natural killer cells in recurrent miscarriage and implantation failure: a systematic review and meta-analysis.

BACKGROUND: Uterine natural killer cells (uNK) are the most abundant lymphocytes found in the decidua during implantation and in first trimester pregnancy. They are important for early placental development, especially trophoblast invasion and transformation of the spiral arteries. However, inappropriate uNK function has been implicated in reproductive failure, such as recurrent miscarriage (RM) or recurrent implantation failure (RIF). Previous studies have mainly focussed on peripheral NK cells (pNK), despite the well-documented differences in pNK and uNK phenotype and function. In recent years, there has been an explosion of studies conducted on uNK, providing a more suitable representation of the immune environment at the maternal-foetal interface. Here, we summarize the evidence from studies published on uNK in women with RM/RIF compared with controls. OBJECTIVE AND RATIONALE: The objectives of this systematic review and meta-analysis are to evaluate: differences in uNK level in women with RM/RIF compared with controls; pregnancy outcome in women with RM/RIF stratified by high and normal uNK levels; correlation between uNK and pNK in women with RM/RIF; and differences in uNK activity in women with RM/RIF compared with controls. SEARCH METHODS: MEDLINE, EMBASE, Web of Science and Cochrane Trials Registry were searched from inception up to December 2020 and studies were selected in accordance with PRISMA guidelines. Meta-analyses were performed for uNK level, pregnancy outcome and uNK/pNK correlation. Narrative synthesis was conducted for uNK activity. Risk of bias was assessed by ROBINS-I and publication bias by Egger's test. OUTCOMES: Our initial search yielded 4636 articles, of which 60 articles were included in our systematic review. Meta-analysis of CD56+ uNK level in women with RM compared with controls showed significantly higher levels in women with RM in subgroup analysis of endometrial samples (standardized mean difference (SMD) 0.49, CI 0.08, 0.90; P = 0.02; I2 88%; 1100 women). Meta-analysis of CD56+ uNK level in endometrium of women with RIF compared with controls showed significantly higher levels in women with RIF (SMD 0.49, CI 0.01, 0.98; P = 0.046; I2 84%; 604 women). There was no difference in pregnancy outcome in women with RM/RIF stratified by uNK level, and no significant correlation between pNK and uNK levels in women with RM/RIF. There was wide variation in studies conducted on uNK activity, which can be broadly divided into regulation and receptors, uNK cytotoxicity, cytokine secretion and effect of uNK on angiogenesis. These studies were largely equivocal in their results on cytokine secretion, but most studies found lower expression of inhibitory receptors and increased expression of angiogenic factors in women with RM. WIDER IMPLICATIONS: The observation of significantly increased uNK level in endometrium of women with RM and RIF may point to an underlying disturbance of the immune milieu culminating in implantation and/or placentation failure. Further research is warranted to elucidate the underlying pathophysiology. The evidence for measuring pNK as an indicator of uNK behaviour is sparse, and of limited clinical use. Measurement of uNK level/activity may be more useful as a diagnostic tool, however, a standardized reference range must be established before this can be of clinical use.

Recurrent gestational diabetes : Breaking the transgenerational cycle with lifestyle modification.

PURPOSE: This literature review is aimed at examining the benefits of lifestyle modifications in preventing recurrent gestational diabetes (GDM). Worldwide GDM affects approximately 16.2% of all pregnancies with significant maternal, fetal and neonatal complications. Almost two thirds of pregnant women with GDM will develop type 2 diabetes mellitus (T2DM) in the years following pregnancy. The proportion of women affected by GDM is on the rise and reflects increasing trends in T2DM as well as adult and childhood obesity. METHODS: Using predefined subject headings, we searched for relevant articles from the PubMed, Scopus, and Cochrane databases. RESULTS: For high-risk women lifestyle modifications, such as dietary and exercise changes, are the mainstay of treatment to reduce negative outcomes for both women and their pregnancies. This includes reducing the incidence of recurrent GDM and future T2DM by intervening during pregnancy and in the postnatal period. CONCLUSION: This review provides an overview of the literature to date, discusses different targeted approaches and how these interventions can optimise their benefits, and where further research is required.

Is there an inflammatory stimulus to human term labour?

Inflammation is thought to play a pivotal role in the onset of term and some forms of preterm labour. Although, we recently found that myometrial inflammation is a consequence rather than a cause of term labour, there are several other reproductive tissues, including amnion, choriodecidua parietalis and decidua basalis, where the inflammatory stimulus to labour may occur. To investigate this, we have obtained amnion, choriodecidual parietalis and decidua basalis samples from women at various stages of pregnancy and spontaneous labour. The inflammatory cytokine profile in each tissue was determine by Bio-Plex Pro® cytokine multiplex assays and quantitative RT-PCR. Active motif assay was used to study transcription activation in the choriodecidua parietalis. Quantitative RT-PCR was use to study the pro-labour genes (PGHS-2, PGDH, OTR and CX43) in all of the tissues at the onset of labour and oxytocin (OT) mRNA expression in the choriodecidual parietalis and decidua basalis. Statistical significance was ascribed to a P value <0.05. In the amnion and choriodecidua parietalis, the mRNA levels of various cytokines decreased from preterm no labour to term no labour samples, but the protein levels were unchanged. The choriodecidua parietalis showed increase in the protein levels of IL-1ß and IL-6 in the term early labour samples. In the amnion and decidua basalis, the protein levels of several cytokines rose in term established labour. The multiples of the median derived from the 19-plex cytokine assay were greater in term early labour and term established labour samples from the choriodecidua parietalis, but only in term established labour for myometrium. These data suggest that the inflammatory stimulus to labour may begin in the choriodecidua parietalis, but the absence of any change in prolabour factor mRNA levels suggests that the cytokines may act on the myometrium where we observed changes in transcription factor activation and increases in prolabour gene expression in earlier studies.

Exploring the knowledge and attitudes of women of reproductive age from the general public towards egg donation and egg sharing: a UK-based study.

STUDY QUESTION: What are the knowledge and views of UK-based women towards egg donation (ED) and egg sharing (ES)? SUMMARY ANSWER: Lacking knowledge of the practices of ED and ES could be an influential factor in donor egg shortages, rather than negative perceptions or lack of donor anonymity and financial incentives. WHAT IS KNOWN ALREADY: The increasing age of women trying to conceive has led to donor egg shortages, with ED and ES failing to meet demand. Indeed, in recent years in the UK, ES numbers have fallen. This results in long waiting lists, forcing patients abroad for fertility treatment to take up cross border reproductive care. Previous research suggests a lack of knowledge of ED among members of the general public; however, no study has yet assessed knowledge or views of ES in the general public. STUDY DESIGN, SIZE, DURATION: Six hundred and thirty-five UK-based women over 18 years were voluntarily recruited from social media community groups by convenience sampling. The recruitment period was from February to April 2020. PARTICIPANTS/MATERIALS, SETTING, METHODS: Participants completed a previously validated questionnaire regarding female fertility, ED and ES, including knowledge, perceptions and approval of the practices and relevant legislation. This included ranking key benefits and issues regarding egg sharing. The questionnaire was completed using the online Qualtrics survey software. Statistical analysis was conducted using SPSS. MAIN RESULTS AND THE ROLE OF CHANCE: Regarding knowledge of ED and ES, 56.3% and 79.8%, respectively had little or no prior knowledge. Upon explanation, most approved of ED (85.8%) and ES (70.4%). A greater proportion of respondents would donate to a family member/friend (49.75%) than to an anonymous recipient (35.80%). Overall, ES was viewed less favourably than ED, with ethical and practical concerns highlighted. Women aged 18-30 years were significantly more likely to approve of egg donation practice compared to those aged >30 years (P < 0.0001). Those against ES found fears of financial coercion or negative psychological wellbeing the most concerning. About 35.8% and 49.7% would personally consider anonymous and known ED, respectively, whilst 56.7% would consider ES. Those answering in favour of egg sharing were significantly more likely to give higher benefit ratings compared to those against the practice (P < 0.001). Most agreed (55.8%) with and were not deterred to donate (60.1%) by the 'Disclosure of Donor Identity' legislation. Only 31.6% agreed with the compensatory cap; however, 52.7% would not be more motivated to donate by an increased cap. LIMITATIONS, REASONS FOR CAUTION: There were several limitations of the study, including the use of convenience sampling and the voluntary nature of participation opening the study up to sampling and participation bias. Finally, closed questions were predominantly used to allow the generation of quantitative data and statistical analysis. However, this approach prevented opinion justification and qualitative analysis, limiting the depth of conclusions drawn. WIDER IMPLICATIONS OF THE FINDINGS: To our knowledge, this is the first study to survey the general public's knowledge and views of ED/ES using a previously validated questionnaire. The conclusion that lack of knowledge could be contributing to the current donor shortfall in the UK demonstrates that campaigns to inform women of the practices are necessary to alleviate donor oocyte shortages. STUDY FUNDING/COMPETING INTEREST(S): No external funds were used for this study. The authors have no conflicts of interest. TRIAL REGISTRATION NUMBER: NA.

Hyponatraemia compounding pre-eclamptic toxaemia in a patient with type 1 diabetes.

We report a case of profound, symptomatic hyponatraemia in association with pre-eclamptic toxaemia (PET) in a 38-year-old nulliparous woman with type 1 diabetes mellitus. This patient developed hypertension and proteinuria at 31+6 weeks' gestation and was admitted for management of pre-eclampsia. Severe headache, visual disturbance and nausea were associated with a hyponatraemia of 115 mmol/L followed by ketoacidosis. This was reversed through fluid restriction, supplementation with 1.8%-3.0% hypertonic saline and a volume-reduced variable-rate insulin infusion. Clinical stability was achieved and she was subsequently worked up for an induction of labour for worsening pre-eclampsia. Hyponatraemia in the context of PET has been previously reported as rare. However, it has complications that may significantly compound the sequelae of severe PET. We propose that specific and focused monitoring of serum sodium levels should become common practice in the management of women with this condition to allow for timely, measured correction of abnormalities.

Is the Host Viral Response and the Immunogenicity of Vaccines Altered in Pregnancy?

The intricacy of the maternal immune system arises from its ability to prevent a maternal immune response against a semi-allogenic fetus, while protecting the mother against harmful pathogens. However, these immunological adaptations may also make pregnant women vulnerable to developing adverse complications from respiratory viral infections. While the influenza and SARS pandemics support this theory, there is less certainty regarding the clinical impact of SARS-CoV-2 in pregnancy. In the current COVID-19 pandemic, vaccine development is key to public preventative strategies. Whilst most viral vaccines are able to induce a seroprotective antibody response, in some high-risk individuals this may not correlate with clinical protection. Some studies have shown that factors such as age, gender, and chronic illnesses can reduce their effectiveness and in this review, we discuss how pregnancy may affect the efficacy and immunogenicity of vaccines. We present literature to support the hypothesis that pregnant women are more susceptible to respiratory viral infections and may not respond to vaccines as effectively. In particular, we focus on the clinical implications of important respiratory viral infections such as influenza during pregnancy, and the pregnancy induced alterations in important leukocytes such as TFH, cTFH and B cells, which play an important role in generating long-lasting and high-affinity antibodies. Finally, we review how this may affect the efficacy of vaccines against influenza in pregnancy and highlight areas that require further research.

Pregnancy Gestation Impacts on HIV-1-Specific Granzyme B Response and Central Memory CD4 T Cells.

Pregnancy induces alterations in peripheral T-cell populations with both changes in subset frequencies and anti-viral responses found to alter with gestation. In HIV-1 positive women anti-HIV-1 responses are associated with transmission risk, however detailed investigation into both HIV-1-specific memory responses associated with HIV-1 control and T-cell subset changes during pregnancy have not been undertaken. In this study we aimed to define pregnancy and gestation related changes to HIV-1-specific responses and T-cell phenotype in ART treated HIV-1 positive pregnant women. Eleven non-pregnant and 24 pregnant HIV-1 positive women were recruited, peripheral blood samples taken, fresh cells isolated, and compared using ELISpot assays and flow cytometry analysis. Clinical data were collected as part of standard care, and non-parametric statistics used. Alterations in induced IFNγ, IL-2, IL-10, and granzyme B secretion by peripheral blood mononuclear cells in response to HIV-1 Gag and Nef peptide pools and changes in T-cell subsets between pregnant and non-pregnant women were assessed, with data correlated with participant clinical parameters and longitudinal analysis performed. Cross-sectional comparison identified decreased IL-10 Nef response in HIV-1 positive pregnant women compared to non-pregnant, while correlations exhibited reversed Gag and Nef cytokine and protease response associations between groups. Longitudinal analysis of pregnant participants demonstrated transient increases in Gag granzyme B response and in the central memory CD4 T-cell subset frequency during their second trimester, with a decrease in CD4 effector memory T cells from their second to third trimester. Gag and Nef HIV-1-specific responses diverge with pregnancy time-point, coinciding with relevant T-cell phenotype, and gestation associated immunological adaptations. Decreased IL-10 Nef and both increased granzyme B Gag response and central memory CD4 T cells implies that amplified antigen production is occurring, which suggests a period of compromised HIV-1 control in pregnancy.

Sepsis: Precision-Based Medicine for Pregnancy and the Puerperium.

Sepsis contributes significantly to global morbidity and mortality, particularly in vulnerable populations. Pregnant and recently pregnant women are particularly prone to rapid progression to sepsis and septic shock, with 11% of maternal deaths worldwide being attributed to sepsis. The impact on the neonate is considerable, with 1 million neonatal deaths annually attributed to maternal infection or sepsis. Pregnancy specific physiological and immunological adaptations are likely to contribute to a greater impact of infection, but current approaches to the management of sepsis are based on those developed for the non-pregnant population. Pregnancy-specific strategies are required to optimise recognition and management of these patients. We review current knowledge of the physiology and immunology of pregnancy and propose areas of research, which may advance the development of pregnancy-specific diagnostic and therapeutic approaches to optimise the care of pregnant women and their babies.

Pregnancy-related immune suppression leads to altered influenza vaccine recall responses.

Pregnancy is a risk factor for severe influenza infection. Despite achieving seroprotective antibody titres post immunisation fewer pregnant women experience a reduction in influenza-like illness compared to non-pregnant cohorts. This may be due to the effects that immune-modulation in pregnancy has on vaccine efficacy leading to a less favourable immunologic response. To understand this, we investigated the antigen-specific cellular responses and leukocyte phenotype in pregnant and non-pregnant women who achieved seroprotection post immunisation. We show that pregnancy is associated with better antigen-specific inflammatory (IFN-γ) responses and an expansion of central memory T cells (Tcm) post immunisation, but low-level pregnancy-related immune regulation (HLA-G, PIBF) and associated reduced B-cell antibody maintenance (TGF-ß) suggest poor immunologic responses compared to the non-pregnant. Thus far, studies of influenza vaccine immunogenicity have focused on the induction of antibodies but understanding additional vaccine-related cellular responses is needed to fully appreciate how pregnancy impacts on vaccine effectiveness.

Progesterone-Related Immune Modulation of Pregnancy and Labor.

Pregnancy involves a complex interplay between maternal neuroendocrine and immunological systems in order to establish and sustain a growing fetus. It is thought that the uterus at pregnancy transitions from quiescent to laboring state in response to interactions between maternal and fetal systems at least partly via altered neuroendocrine signaling. Progesterone (P4) is a vital hormone in maternal reproductive tissues and immune cells during pregnancy. As such, P4 is widely used in clinical interventions to improve the chance of embryo implantation, as well as reduce the risk of miscarriage and premature labor. Here we review research to date that focus on the pathways through which P4 mediates its actions on both the maternal reproductive and immune system. We will dissect the role of P4 as a modulator of inflammation, both systemic and intrinsic to the uterus, during human pregnancy and labor.

Progesterone Modulation of Pregnancy-Related Immune Responses.

Progesterone (P4) is an important steroid hormone for the establishment and maintenance of pregnancy and its functional withdrawal in reproductive tissue is linked with the onset of parturition. However, the effects of P4 on adaptive immune responses are poorly understood. In this study, we took a novel approach by comparing the effects of P4 supplementation longitudinally, with treatment using a P4 antagonist mifepristone (RU486) in mid-trimester pregnancies. Thus, we were able to demonstrate the immune-modulatory functions of P4. We show that, in pregnancy, the immune system is increasingly activated (CD38, CCR6) with greater antigen-specific cytotoxic T cell responses (granzyme B). Simultaneously, pregnancy promotes a tolerant immune environment (IL-10 and regulatory-T cells) that gradually reverses prior to the onset of labor. P4 suppresses and RU486 enhances antigen-specific CD4 and CD8 T cell inflammatory cytokine (IFN-γ) and cytotoxic molecule release (granzyme B). P4 and RU486 effectively modulate immune cell-mediated interactions, by regulating differentiated memory T cell subset sensitivity to antigen stimulation. Our results indicate that P4 and RU486, as immune modulators, share a reciprocal relationship. These data unveil key contributions of P4 to the modulation of the maternal immune system and suggests targets for future modulation of maternal immune function during pregnancy.

Changes in T Cell and Dendritic Cell Phenotype from Mid to Late Pregnancy Are Indicative of a Shift from Immune Tolerance to Immune Activation.

During pregnancy, the mother allows the immunologically distinct fetoplacental unit to develop and grow. Opinions are divided as to whether this represents a state of fetal-specific tolerance or of a generalized suppression of the maternal immune system. We hypothesized that antigen-specific T cell responses are modulated by an inhibitory T cell phenotype and modified dendritic cell (DC) phenotype in a gestation-dependent manner. We analyzed changes in surface markers of peripheral blood T cells, ex vivo antigen-specific T cell responses, indoleamine 2,3-dioxygenase (IDO) activity (kynurenine/tryptophan ratio, KTR), plasma neopterin concentration, and the in vitro expression of progesterone-induced blocking factor (PIBF) in response to peripheral blood mononuclear cell culture with progesterone. We found that mid gestation is characterized by reduced antigen-specific T cell responses associated with (1) predominance of effector memory over other T cell subsets; (2) upregulation of inhibitory markers (programmed death ligand 1); (3) heightened response to progesterone (PIBF); and (4) reduced proportions of myeloid DC and concurrent IDO activity (KTR). Conversely, antigen-specific T cell responses normalized in late pregnancy and were associated with increased markers of T cell activation (CD38, neopterin). However, these changes occur with a simultaneous upregulation of immune suppressive mechanisms including apoptosis (CD95), coinhibition (TIM-3), and immune regulation (IL-10) through the course of pregnancy. Together, our data suggest that immune tolerance dominates in the second trimester and that it is gradually reversed in the third trimester in association with immune activation as the end of pregnancy approaches.