Pregnancy in women with congenital heart disease: New insights into neonatal risk prediction.

BACKGROUND: Advances in managing adult congenital heart disease (ACHD) have led to an increased number of women with CHD reaching childbearing age. This demographic shift underscores the need for improved understanding and prediction of complications during pregnancy in this specific ACHD population. Despite progress in maternal cardiac risk assessment, the prediction of neonatal outcomes for ACHD pregnancies remains underdeveloped. Therefore, the aims of this study are to assess neonatal outcomes in a CHD women population, to identify their predictive factors and to propose a new risk score for predicting neonatal complications. METHODS: This registry study included all women born between 1975 and 1996 diagnosed with ACHD who underwent at least one cardiology consultation for ACHD in Cliniques Universitaires Saint-Luc. A multivariate analysis was performed to identify predictors of neonatal complications and these were incorporated into a new risk index. Its validity was assessed using bootstrap method. This score was then compared with scores adapted from the ZAHARA and CARPREG studies for offspring events prediction. RESULTS: Analysis of 491 pregnancies revealed 31.4% of neonatal complications. Four significant predictors of adverse neonatal outcomes were identified: cardiac treatment during pregnancy (OR 14.8, 95%CI [3.4-66]), hypertensive disorders of pregnancy (OR 11.4, 95%CI [3.4-39.0]), smoking during pregnancy (OR 10.6, 95%CI [2.8-40.6]), and pre-pregnancy BMI <18.5 kg/m² (OR 6.5, 95%CI [2.5-16.5]). The risk model demonstrated an AUC of 0.70 (95%CI [0.65-0.75]), which remained stable after bootstrap validation. This model significantly outperformed the scores adapted from ZAHARA and CARPREG data. Based on the regression coefficients, a risk score was subsequently developed comprising five risk categories. CONCLUSIONS: One third of ACHD pregnancies are complicated by poor neonatal outcome. These complications are determined by four independent factors relating to the cardiac and non-cardiac status of the patients, which have been incorporated into a risk score. Our study is one of the first to propose a predictive risk score of neonatal outcomes in ACHD pregancies, and paves the way for other validation and confirmation studies.

Implementing intact cord resuscitation in very preterm infants: feasibility and pitfalls.

The purpose of this study is to evaluate the feasibility of intact cord resuscitation (ICR) in very preterm infants using a custom-equipped mobile resuscitation trolley (LifeStart®). We collected maternal and neonatal data of all inborn infants < 32 weeks eligible for ICR per our protocol over 9 months from ICR implementation. We compared rates of ICR between the beginning and the end of the study period. We reviewed maternal and neonatal adverse events related to the procedure and direct outcomes. In order to assess potential quality improvements related to the procedure, we collected the same data in the infants born in the 9-month period preceding ICR implementation. Out of 44 infants born < 32 weeks during the period, 27 were eligible for ICR. Failure to initiate ICR occurred in 9/27, exclusively in the first 5.5 months of the study. In one infant, ICR was interrupted prior to 2 min due to placental abruption. No ICR procedure had to be interrupted due to insufficient cord length. Among the 18 infants who completed ICR, cord clamping timing increased significantly over the study period, from 3.0 [2.5-3.5] to 4.2 min [3.1-8.3] (p = 0.02). No significant maternal blood loss or wound complications were noted. No infant deaths were attributable to failure or direct consequence of ICR, and no infant experienced hypoxic respiratory failure (intubation, FiO2 ≥ 0.4), asphyxia (pH < 7.2), or blood pressure instability (< 2 SD) following stabilization. Hemoglobin level after cord clamping was higher in the ICR cohort than in the pre-implementation group. Seven out of 18 infants exposed to ICR had a temperature < 36.5 °C on admission.   Conclusion: ICR is feasible in very preterm infants. Temperature management requires special attention. Multidisciplinary simulation training before implementation and systematic post-implementation quality improvement meetings may significantly increase ICR program success. What is Known: • Because infants born < 32 weeks often require cardiorespiratory resuscitation at birth, they are not offered delayed cord clamping in the majority of neonatal intensive care units. • Recently, fully equipped mobile trolleys have been developed in order to allow bedside resuscitation with an intact cord. What is New: • Variable timing of cord clamping based on the infant's transition and respiratory stability, i.e., "physiology-based cord clamping," is safely achievable in very preterm infants. • Intact cord resuscitation requires specific equipment, operational protocols, and a high level of preparation from both obstetrical and neonatal teams, with a learning curve that can be streamlined by multidisciplinary simulation training.

Clinical and in Vitro Evidence against Placenta Infection at Term by Severe Acute Respiratory Syndrome Coronavirus 2.

Despite occasional reports of vertical transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during pregnancy, the question of placental infection and its consequences for the newborn remain unanswered. Herein, we analyzed the placentas of 31 coronavirus disease 2019-positive mothers by reverse transcriptase PCR, immunohistochemistry, and in situ hybridization. Only one case of placental infection was detected, which was associated with intrauterine demise of the fetus. Differentiated primary trophoblasts were then isolated from nonpathologic human placentas at term, differentiated, and exposed to SARS-CoV-2 virions. Unlike for positive control cells Vero E6, the virus inside cytotrophoblasts and syncytiotrophoblasts or in the supernatant 4 days after infection was undetectable. As a mechanism of defense, we hypothesized that trophoblasts at term do not express angiotensin-converting enzyme 2 and transmembrane protease serine 2 (TMPRSS2), the two main host membrane receptors for SARS-CoV-2 entry. The quantification of these proteins in the placenta during pregnancy confirmed the absence of TMPRSS2 at the surface of the syncytium. Surprisingly, a transiently induced experimental expression of TMPRSS2 did not allow the entry or replication of the virus in differentiated trophoblasts. Altogether, these results underline that trophoblasts are not likely to be infected by SARS-CoV-2 at term, but raise concern about preterm infection.

Hypoxia-inducible factor 2 alpha impairs human cytotrophoblast syncytialization: New insights into placental dysfunction and fetal growth restriction.

Insufficient remodeling of uterine arteries causes pregnancy-related diseases, including fetal growth restriction and preeclampsia. In these situations, reduced maternal blood flow in the placenta is thought to be responsible for the persistence of a low oxygen environment throughout pregnancy. We hypothesized that chronic activation of transcription factors hypoxia-inducible factors (HIFs) actively participates in placental underdevelopment, which impairs fetal growth. The computer-assisted analysis in pathological placentas revealed an increased number of HIF-2α-positive nuclei in the syncytium compared to normal human placentas, while HIF-1α stabilization was unchanged. Specific involvement of HIF-2α was confirmed in primary human cytotrophoblasts rendered deficient for HIF1A or HIF2A. Silencing HIF2A increased the expression of main syncytialization markers as well as differentiation and syncytium formation. It also improved placental growth factor bioavailability. None of these changes was seen when silencing HIF1A. Conversely, the experimental induction of HIF-2α expression repressed forskolin-induced differentiation in BeWo choriocarcinoma cells. Our mechanistic insights evidence that transcription factor HIF-2α impairs placental function, thus suggesting its participation in fetal growth restriction and preeclampsia when placentas become chronically hypoxic. Furthermore, it suggests the possibility to develop novel molecular targeting therapies for placental dysfunction.

Impaired vascular endothelial growth factor expression and secretion during in vitro differentiation of human primary term cytotrophoblasts.

Vascular endothelial growth factor A (VEGF-A) is one of the main growth factors involved in placental vasculogenesis and angiogenesis, but its placental expression is still ambiguous. During in vitro cultures of primary term cytotrophoblasts, VEGF could not be detected in the supernatants by enzyme-linked immunosorbent assays (ELISA). One hypothesis is that VEGF is immediately and completely bound to its soluble receptor after secretion, and cannot be recognized by the antibodies used in the commercial ELISA kits. We decided to verify this hypothesis by measuring VEGF-A expression during in vitro cultures of primary term cytotrophoblasts. Term cytotrophoblasts were cultured under 21% and 2.5% O2 for 4 days. VEGF-A transcripts were quantified by real-time polymerase chain reaction. The proteins from cell lysates and concentrated media were separated by polyacrylamide gel electrophoresis (PAGE) under denaturing and reducing conditions, and VEGF-A immunodetected by western blotting. VEGF mRNA expression did not increase during in vitro cell differentiation under 21% O2, but slightly increased under 2.5% O2 only at 24 h. VEGF-A monomer was not detected in the cell lysates and in the concentrated supernatants, while a ~ 42 KDa band corresponding to the precursor L-VEGF was detected in all the cellular extracts. Isolated term villous cytotrophoblasts produce the L-VEGF precursor but they do not secrete VEGF-A even under low-oxygen tension. The question remains about the origin of VEGF in pregnancy but also about the biological role of L-VEGF, which can represent a form of storage for rapid VEGF secretion when needed.

Effects of chemotherapy on placental development and function using in vitro culture of human primary cytotrophoblasts.

Introduction Cancers during pregnancy can be treated with chemotherapy after the first trimester but the treatment is associated with smaller placentas and an increased risk of stillbirth, fetal growth retardation and preterm delivery. We decided to assess the effect of several chemotherapeutic agents on placental development by using in vitro culture of human term cytotrophoblasts. Methods Cytotrophoblasts isolated from term placentas were cultured for 48 h and treated for 24 h with epirubicin, docetaxel, vinblastine, methotrexate, tamoxifen, 4-hydroxytamoxifen, and endoxifen. First, cell viability was assessed. Then, the effect of the treatment on trophoblast differentiation and placental angiogenesis was assessed by quantifying hCG and PlGF mRNA and protein expression. Finally, the expression of two efflux transporters, BCRP and MDR1 was investigated. Results Epirubicin only strongly decreased cell viability. Epirubicin, docetaxel, and vinblastine inhibited HCGB and PlGF expression while methotrexate, tamoxifen and its two metabolites increased it. BCRP was essentially expressed in syncytiotrophoblasts and MDR1 in undifferentiated cytotrophoblasts. Their expression was not affected by the drugs but vinblastine increased BCRP mRNA expression by 2.8-fold. Discussion The most commonly used chemotherapeutic drugs are well supported in vitro by syncytiotrophoblasts, except for epirubicin, which was very cytotoxic. Chemotherapy perturbed the expression of genes normally upregulated during placental differentiation and angiogenesis but not the expression of the drug transporters. Further studies looking at the effect of combination therapy and the transporter capacities to reject the drugs will be needed to better define the effects of chemotherapy on placental development and function.

Anomalies of the placenta and umbilical cord in twin gestations.

The frequency of twin gestations has increased over the last few decades, mainly due to maternal age at childbearing, and the use of assisted reproductive technologies. Twins are at higher risk of aneuploidy, structural anomalies, and placental abnormalities. Some of the placental and umbilical cord abnormalities found in twin gestations are nonspecific and can be found in singleton gestations (ie, placenta previa, placental abruption, single umbilical artery, velamentous cord insertion, vasa previa, etc). However, other anomalies are unique to twin gestations, and are mainly associated with monochorionic twins-these include intraplacental anastomosis and cord entanglement. Most of these conditions can be diagnosed with ultrasound. An accurate and early diagnosis is important in the management of twin gestations. Determination of chorionicity, amnionicity, and the identification of placental anomalies are key issues for the adequate management of twin pregnancies. Pathologic placental examination after delivery can help in assessing the presence of placental and umbilical cord abnormalities, as well as providing information about chorionicity and gaining insight into the potential mechanisms of disease affecting twin gestations.

Inhibin alpha gene expression in human trophoblasts is regulated by interactions between TFAP2 and cAMP signaling pathways.

Inhibin α (Inha) gene expression is regulated, in rat granulosa cells, via a cyclic 3',5'-adenosine monophosphate (AMP)-response element (CRE) found in a region of the promoter that is homologous to the human INHA promoter. We previously found that during in vitro cytotrophoblast differentiation, human INHA gene expression was regulated by TFAP2A via association with an AP-2 site located upstream of this CRE. The aim of this study was to evaluate if the human INHA gene was also regulated by cAMP in trophoblasts, and to investigate the possible crosstalk between TFAP2 and cAMP signaling pathways in the regulation of INHA gene expression. Treatment with cAMP or forskolin increased INHA mRNA expression by 7- and 2-fold in primary cytotrophoblasts and choriocarcinoma-derived BeWo cells, respectively. Treatment with the protein kinase A inhibitor H-89 reduced forskolin-induced luciferase activity by ∼40% in BeWo cells transfected with an INHA promoter-driven luciferase reporter vector. TFAP2 overexpression increased basal luciferase activity, whereas the dominant repressor KCREB abolished it. Surprisingly, mutation of the CRE also eliminated the TFAP2-induced transcription, although TFAP2 overexpression was still able to increase forskolin-induced luciferase activity when the AP-2 binding site, but not the CRE site, was mutated. Thus, INHA gene expression is upregulated by cAMP via CRE in human trophoblasts, and TFAP2 regulates this expression by interacting with CRE.

Gene therapy in preeclampsia: the dawn of a new era.

Preeclampsia is a severe complication of pregnancy, affecting an estimated 4 million women annually. It is one of the leading causes of maternal and fetal mortality worldwide, and it has life-long consequences. The maternal multisystemic symptoms are driven by poor placentation, which causes syncytiotrophoblastic stress and the release of factors into the maternal bloodstream. Amongst them, the soluble fms-like tyrosine kinase-1 (sFLT-1) triggers extensive endothelial dysfunction by acting as a decoy receptor for the vascular endothelial growth factor (VEGF) and the placental growth factor (PGF). Current interventions aim to mitigate hypertension and seizures, but the only definite treatment remains induced delivery. Thus, there is a pressing need for novel therapies to remedy this situation. Notably, CBP-4888, a siRNA drug delivered subcutaneously to knock down sFLT1 expression in the placenta, has recently obtained Fast Track approval from the Food and Drug Administration (FDA) and is undergoing a phase 1 clinical trial. Such advance highlights a growing interest and significant potential in gene therapy to manage preeclampsia. This review summarizes the advances and prospects of gene therapy in treating placental dysfunction and illustrates crucial challenges and considerations for these emerging treatments.

Long-term hypothyroidism in patients started on levothyroxine during pregnancy.

Background: Current guidelines recommend different postpartum approaches for patients started on levothyroxine (LT4) during pregnancy. Objective: We studied the postpartum management of these patients and determined factors associated with long-term hypothyroidism. Methods: A retrospective study was conducted at a tertiary center between 2014 and 2020, with LT4 initiation according to 2014 ETA recommendations. We performed multivariate logistic regression (MVR) and a receiver operating characteristic curve analysis to determine variables associated with long-term hypothyroidism and their optimal cutoffs. Results: LT4 was initiated in 177 pregnant women, and 106/177 (60%) were followed at long-term (at least 6 months post partum) (28.5 (9.0-81.9) months). LT4 could have been stopped in 45% of patients who continued it immediately after delivery. Thirty-six out of 106 (34%) patients were long-term hypothyroid. In them, LT4 was initiated earlier during pregnancy than in euthyroid women (11.7 ± 4.7 vs 13.7 ± 6.5 weeks, P = 0.077), at a higher thyroid-stimulating hormone (TSH) level (4.1 (2.2-10.1) vs 3.5 (0.9-6.9) mU/L, P = 0.005), and reached a higher dose during pregnancy (62.8 ± 22.2 vs 50.7 ± 13.9 µg/day, P = 0.005). In the MVR, only the maximal LT4 dose during pregnancy was associated with long-term hypothyroidism (odds ratio (OR) = 1.03, 95% CI: 1.00-1.05, P = 0.003). The optimal cutoffs for predicting long-term hypothyroidism were an LT4 dose of 68.75 µg/day (87% specificity, 42% sensitivity; P = 0.013) and a TSH level ≥ 3.8 mU/L (68.5% specificity, 77% sensitivity; P = 0.019). Conclusion: One-third of the patients who started on LT4 during pregnancy had long-term hypothyroidism. The TSH level at treatment initiation and the LT4 dose during pregnancy could guide the decision for continuing long-term LT4.

Fetal rat hearts do not display acute cardiotoxicity in response to maternal Doxorubicin treatment.

Anthracyclines are used to treat cancers during the second and third trimester of pregnancy. The chemotherapeutic effect of anthracyclines is associated with a dose- and time-dependent cardiotoxicity that is well described for infants and adults. However, data regarding fetal anthracycline-related cardiotoxicity after administration of chemotherapeutics during pregnancy are limited. In this study, we analyzed the acute effect of doxorubicin, an anthracycline derivative, on fetal and maternal rat myocardium. We injected 10 or 20 mg/kg i.v. doxorubicin to pregnant Wistar rats at day 18 of pregnancy; age-matched pregnant rats injected with physiologic saline served as controls. Maternal echocardiography and fetal Doppler scanning were performed before the injection and before sacrifice. Cesarean operation was performed at day 19 or 20, and maternal and fetal blood samples and heart biopsies were collected to measure apoptosis, the impact on cell proliferation, and structural cardiac damage. Acute maternal cardiotoxicity is associated with loss of body weight, moderately deteriorated left ventricular function, induction of apoptosis, and a decrease in cell turnover. Despite a 30% lower fetal body weight and elevated plasma B-type natriuretic peptide concentrations after doxorubicin administration, the fetal hearts had intact microstructure, an unaltered number of apoptotic cells, and preserved cell proliferation compared with controls. Our study suggests that acute treatment using anthracyclines during pregnancy impairs maternal cardiac function, whereas fetal hearts are protected.

Specific HIF-2α (Hypoxia-Inducible Factor-2) Inhibitor PT2385 Mitigates Placental Dysfunction In Vitro and in a Rat Model of Preeclampsia (RUPP).

BACKGROUND: Preeclampsia is one of the leading causes of maternal mortality worldwide and is strongly associated with long-term morbidity in mothers and newborns. Referred to as one of the deep placentation disorders, insufficient remodeling of the spiral arteries during the first trimester remains a major cause of placental dysfunction. Persisting pulsatile uterine blood flow causes abnormal ischemia/reoxygenation phenomenon in the placenta and stabilizes the HIF-2α (hypoxia-inducible factor-2α) in the cytotrophoblasts. HIF-2α signaling impairs trophoblast differentiation and increases sFLT-1 (soluble fms-like tyrosine kinase-1) secretion, which reduces fetal growth and causes maternal symptoms. This study aims to evaluate the benefits of using PT2385-an oral specific HIF-2α inhibitor-to treat severe placental dysfunction. METHODS: To evaluate its therapeutic potential, PT2385 was first studied in primary human cytotrophoblasts isolated from term placenta and exposed to 2.5% O2 to stabilize HIF-2α. Viability and luciferase assays, RNA sequencing, and immunostaining were used to analyze differentiation and angiogenic factor balance. The ability of PT2385 to mitigate maternal manifestations of preeclampsia was studied in the selective reduced uterine perfusion pressure model performed in Sprague-Dawley rats. RESULTS: In vitro, RNA sequencing analysis and conventional techniques showed that treated cytotrophoblast displayed an enhanced differentiation into syncytiotrophoblasts and normalized angiogenic factor secretion compared with vehicle-treated cells. In the selective reduced uterine perfusion pressure model, PT2385 efficiently decreased sFLT-1 production, thus preventing the onset of hypertension and proteinuria in pregnant dams. CONCLUSIONS: These results highlight HIF-2α as a new player in our understanding of placental dysfunction and support the use of PT2385 to treat severe preeclampsia in humans.

Effects of chemotherapy during pregnancy on the maternal and fetal heart.

OBJECTIVE: The co-occurrence of cancer and pregnancy is more frequently diagnosed. The effects of cancer treatment on maternal and fetal outcomes are less well known. The cardiotoxic effects of chemotherapy are a specific concern for the mother and fetus. We wanted to review the existing literature, mainly consisting of case reports, case studies, and retrospective data. RESULTS: Maternal effects Overall, the published data indicate that pregnancy is not an independent risk factor influencing cancer survival. There is no indirect evidence for an increased risk for maternal chemotherapy-related cardiotoxicity. Fetal effects During the first trimester chemotherapy needs to be avoided because of teratogenic risks. The risks of chemotherapy during the second and third trimester are more controversial. It has been associated with intrauterine growth restriction and preterm delivery in some studies, while others did not find the same effect. Cardiotoxic fetal effects have been reported despite the limited transplacental passage of chemotherapy. In most patients this was transient and long-term data are generally reassuring. CONCLUSION: A specific strategy for monitoring fetal and maternal chemotherapy-induced cardiotoxicity is suggested. Prospective data are needed on the long-term effects of chemotherapy in both mother and child.

Chemotherapy during pregnancy: effect of anthracyclines on fetal and maternal cardiac function.

Chemotherapy and especially anthracyclines are associated to cardiotoxicity. To assess this potential risk during pregnancy a clinical case-control trial was conducted. Maternal cardiac function, fetal Doppler and fetal cardiac function were evaluated before and after chemotherapy. Maternal cardiac function was assessed by echocardiography before and after the third cycle of anthracyclines and compared with a control group of 10 non-pregnant women matched for age, type of cancer and anthracycline treatment. Ten fetuses exposed to chemotherapy were compared with 10 control fetuses matched for gestational age and gender. Biometry, amniotic fluid index, fetal Doppler and cardiac function were assessed before and after each cycle of chemotherapy. In all, 108 fetal ultrasounds scans were performed before and after 36 cycles of chemotherapy. Anthracycline exposure did not result in acute maternal and fetal cardiac dysfunction in this small cohort study.

Reduction of miscarriages through universal screening and treatment of thyroid autoimmune diseases.

BACKGROUND/AIMS: Universal screening for thyroid diseases during pregnancy is controversial. Targeted screening does not identify all women with thyroid dysfunction. Furthermore, antithyroid peroxidase antibodies (TPOAb) are suspected to be associated with an increased risk of fetal loss, premature delivery and hypothyroidism. The aim of our study was to assess the rationale behind universal screening and propose thyroxine treatment in particular cases. METHODS: Between January 2008 and May 2009, 537 consecutive iodine-supplemented women with a singleton pregnancy [441 TPOAb- controls and 96 TPOAb+ women (47 nontreated and 49 treated)] were evaluated using thyroid and obstetric parameters. According to our algorithm for thyroid screening in pregnancy, if thyroid-stimulating hormone (TSH) exceeded 1 mU/l in TPOAb+ women, 50 µg of levothyroxine (L-T4) was prescribed. RESULTS: The miscarriage rate was significantly higher in the nontreated TPOAb+ group compared with the treated group (16 vs. 0%; p = 0.02). Compared to the control group, TSH in TPOAb+ patients was higher at the first prenatal visit prior to L-T4 treatment (p < 0.01), while free thyroxine was higher than in the control group after the 20th week (p < 0.05). CONCLUSIONS: Our study supports the potential benefit of universal screening and L-T4 treatment for autoimmune thyroid disease during pregnancy. Efforts are still needed to further decrease miscarriage rates.

Pregnancy Outcomes After Kidney Transplantation and Long-Term Evolution of Children: A Single Center Experience.

BACKGROUND: Pregnancies in women who underwent kidney transplants are at high risk compared with the general population. METHODS: In this study, we aimed to retrospectively assess the obstetrical complications, delivery outcomes, and impact of pregnancy on kidney allograft function in a single-center cohort of kidney transplant recipients (KTRs). We provide data regarding the long-term evolution of children. RESULTS: Thirty-two KTRs underwent a total of 57 pregnancies between 1994 and 2010. Fourteen pregnancies (24 %) did not survive caused by miscarriages (n = 9), stillborn (n = 1), ectopic pregnancies (n = 2), and medical abortion (n = 2). Live birth occurred in 76% of pregnancies. Delivery was by cesarean in 66%. The mean gestational age was 30.45 ± 11.3 weeks and 65% of newborns were premature. A low birth weight <2500g was noted in 46%. Obstetric complications were de novo hypertension in 4%, pre-eclampsia in 9%, and gestational diabetes in 2%. The 5- and 10-year post-delivery death-censored graft loss rates were 3.1% and 12.5%, respectively. Data on 21 children were collected via a self-questionnaire. After a median follow-up time of 17 years, they appeared in good medical and psychological health. None of them suffered from chronic disease (especially uronephrological condition) or was taking chronic medication. CONCLUSIONS: Long-term evolution of children born to women who underwent kidney transplants seems favorable. Pregnancies in KTRs are successful in two-thirds of cases but are at increased risk of prematurity, delivery by cesarean, and low birth weight.

Evaluation of a universal real-time polymerase chain reaction for detection of amniotic fluid infection in premature rupture of membranes.

Managing preterm rupture of membranes (PPROM) is a balance between benefits of prolonging gestation and the risks of perinatal infection. This study evaluates a real-time polymerase chain reaction (PCR) for the detection of amniotic fluid infection and neonatal complications by amniocentesis following PPROM. A total of 61 singleton pregnancies with PPROM were analyzed retrospectively, including histopathologic examination of the placenta and neonatal complications. The real-time PCR detects a highly conserved sequence of the bacterial 16S ribosomal DNA, and its efficacy was compared with standard tests including amniotic fluid glucose concentration, lactate dehydrogenase level, and maternal white cells count and C-reactive protein levels. Sensitivity and specificity were similar for PCR (64% and 85%) and standard tests (58% and 80%). However, the PCR technique has the additional advantage of possible identification of the bacteria through sequencing and has a much better positive predictive value in the occurrence of neonatal complications (60% for PCR versus 35% for standard tests). The latency period between premature rupture of the membranes and delivery was not related to the incidence of histopathologic signs of infection in the placenta or the umbilical cord and was inversely related to the incidence of neonatal complications.

Adaptations of the human placenta to hypoxia: opportunities for interventions in fetal growth restriction.

BACKGROUND: The placenta is the functional interface between the mother and the fetus during pregnancy, and a critical determinant of fetal growth and life-long health. In the first trimester, it develops under a low-oxygen environment, which is essential for the conceptus who has little defense against reactive oxygen species produced during oxidative metabolism. However, failure of invasive trophoblasts to sufficiently remodel uterine arteries toward dilated vessels by the end of the first trimester can lead to reduced/intermittent blood flow, persistent hypoxia and oxidative stress in the placenta with consequences for fetal growth. Fetal growth restriction (FGR) is observed in ∼10% of pregnancies and is frequently seen in association with other pregnancy complications, such as preeclampsia (PE). FGR is one of the main challenges for obstetricians and pediatricians, as smaller fetuses have greater perinatal risks of morbidity and mortality and postnatal risks of neurodevelopmental and cardio-metabolic disorders. OBJECTIVE AND RATIONALE: The aim of this review was to examine the importance of placental responses to changing oxygen environments during abnormal pregnancy in terms of cellular, molecular and functional changes in order to highlight new therapeutic pathways, and to pinpoint approaches aimed at enhancing oxygen supply and/or mitigating oxidative stress in the placenta as a mean of optimizing fetal growth. SEARCH METHODS: An extensive online search of peer-reviewed articles using PubMed was performed with combinations of search terms including pregnancy, placenta, trophoblast, oxygen, hypoxia, high altitude, FGR and PE (last updated in May 2020). OUTCOMES: Trophoblast differentiation and placental establishment are governed by oxygen availability/hypoxia in early pregnancy. The placental response to late gestational hypoxia includes changes in syncytialization, mitochondrial functions, endoplasmic reticulum stress, hormone production, nutrient handling and angiogenic factor secretion. The nature of these changes depends on the extent of hypoxia, with some responses appearing adaptive and others appearing detrimental to the placental support of fetal growth. Emerging approaches that aim to increase placental oxygen supply and/or reduce the impacts of excessive oxidative stress are promising for their potential to prevent/treat FGR. WIDER IMPLICATIONS: There are many risks and challenges of intervening during pregnancy that must be considered. The establishment of human trophoblast stem cell lines and organoids will allow further mechanistic studies of the effects of hypoxia and may lead to advanced screening of drugs for use in pregnancies complicated by placental insufficiency/hypoxia. Since no treatments are currently available, a better understanding of placental adaptations to hypoxia would help to develop therapies or repurpose drugs to optimize placental function and fetal growth, with life-long benefits to human health.

Isolation of Primary Cytotrophoblasts From Human Placenta at Term.

The placenta is a multifaceted organ, fulfilling critical functions for the fetus and the mother. Therefore, it is a critical regulator of the pregnancy, and its dysfunction leads to diseases, including fetal growth restriction and preeclampsia. Studying the placenta is a difficult task since its existence is transient, and its structure is specific to our species. In vitro differentiation of primary cytotrophoblast isolated from term human placenta has been widely used in the placental research field as it represents a reliable model to study cellular differentiation and function. Direct alternatives include trophoblastic cell lines, explants, and organoids, but this protocol, based on the separation of the cells on a Percoll gradient, presents the advantage of being relatively cheap and easy to perform in every research laboratory. Furthermore, the 2D culture is a flexible method that can be adapted to various experimental conditions (transfection, drug exposure, metabolic study, observations, etc.), allowing mechanistic explorations of cellular processes.