Complement Split Products in Amniotic Fluid in Pregnancies Subsequently Developing Early-Onset Preeclampsia

The interval between the onset of increased blood pressure and proteinuria in preeclampsia and the contributing factors

PURPOSE

New-onset proteinuria, as a pivotal sign of representative renal lesions in preeclampsia, is still the most common diagnostic tool for this condition and has been proven to be related to a significantly abnormal sFlt-1/VEGF ratio in circulation. At the same time, blood pressure control plays a vital role in the occurrence and evolution of proteinuria. Therefore, it is particularly helpful to investigate their interval, not only for performing urinalysis for protein more accurately but also for evaluating blood pressure as well as the aggravation of illness, as the related research is limited.

METHODS

This retrospective study included 515 preeclampsia patients and 358 normotensive pregnant women who labored in the Second Hospital of Tianjin Medical University from January 2016 to January 2020. First, we described the onset circumstance of high blood pressure and proteinuria as well as the interval among the case group and the subgroups. Then, we determined whether there were significant differences in the basic information, laboratory test results, and newborns between the case and normal groups. Finally, multifactor ANOVA was used to determine the factors influencing the interval.

RESULTS

1. The two most common complications in preeclampsia were proteinuria (88.35%) and placental dysfunction (5.05%). Moreover, 72.04% of preeclampsia cases were diagnosed by abnormal blood pressure together with new-onset proteinuria. 2. The average interval between high blood pressure and proteinuria was 22 gestational days (from 0 to 106 days), and this interval was not significantly different between mild and severe PE (26 days vs. 21 days, P > 0.05) but significantly differed between early-onset and late-onset PE (9 days vs. 28 days, P < 0.05). 3. The number of prenatal visits, serum creatinine in the early trimester, gestational time and diastolic blood pressure value when increased blood pressure was initially detected may influence the interval between the onset of increased blood pressure and proteinuria.

CONCLUSION

New-onset proteinuria was still the main parameter for identifying preeclampsia. The interval between increased blood pressure and proteinuria was probably related to the imbalance in the sFlt-1/VEGF ratio; therefore, we should pay attention to monitor proteinuria during the prenatal visits, especially for patients with a lower frequency of prenatal visits, higher serum creatinine in the early trimester, earlier onset and higher diastolic blood pressure at the initial onset of increased blood pressure.

The evaluation of some serum immunochemical markers in early onset pre-eclamptic women from Algeria

PROBLEM

Progress in understanding the underlying mechanism responsible for the syndrome pre-eclampsia should reconfigure antenatal clinical care and minimize human and financial costs, yet at present there is no accurate theory that permits development of reliable predictive tests and prophylactic intervention to mitigate disease. To contribute to this ongoing effort, we aimed to assess various circulating markers pertaining to different theories.

METHOD OF STUDY

Serum samples from thirty-four women with established early onset preeclampsia (ePE) were assessed in terms of oxidative stress (malondialdehyde- MDA), angiogenic status (PlGF & sFLT-1), complement system (The alternative pathway -AP₅₀ & complement factor H- CFH) and circulating inflammatory markers (Interleukin 6- IL-6 & Procalcitonin- PCT). Control groups of gestational age matched patients included 20 gestational hypertensive (GH) and 6 normotensive pregnant women (NPW).

RESULTS

Our work shows that PlGF is the only serum marker who does exhibit a continued decrease from NPW to GH to ePE (r_pearson = -0.428, p = .002). The ePE group had a profound impairment in circulating PlGF (66.93 ± 20.62 pg/ml) compared to GH (142.67 ± 39.79 pg/ml; p = .069) and NPW (636.83 ± 392.66 pg/ml; p = .002). Then, PlGF >71.29 pg/ml pg/ml is the cut-off that has the highest negative predictive value enabling exclusion of ePE (Sp 78%, Se 70%, p = .000). No such interesting results could be obtained with the other markers.

CONCLUSION

Our data confirm that the angiogenic factor PlGF may be highly relevant in biological mechanisms underlying the development of ePE. This article is protected by copyright. All rights reserved.

Maternal serum proteomic profiles of pregnant women with type 1 diabetes

Despite improvement in the care of diabetes over the years, pregnancy complicated by type 1 diabetes (T1DM) is still associated with adverse maternal and neonatal outcomes. To date, proteomics studies have been conducted to identify T1DM biomarkers in non-pregnant women, however, no studies included T1DM pregnant women. In this study serum proteomic profiling was conducted in pregnant women with T1DM in the late third trimester. Serum samples were collected from 40 women with T1DM and 38 healthy controls within 3 days before delivery at term pregnancy. Significant differences between serum proteomic patterns were revealed, showing discriminative peaks for complement C3 and C4-A, kininogen-1, and fibrinogen alpha chain. Quantification of selected discriminative proteins by ELISA kits was also performed. The serum concentration of kininogen-1 was significantly lower in women with T1DM than in controls. There were no significant differences in serum concentrations of complement C3 and complement C4-A between study groups. These data indicate that pregnant women with T1DM have a distinct proteomic profile involving proteins in the coagulation and inflammatory pathways. However, their utility as biomarkers of pregnancy complications in women with T1DM warrants further investigation.

Molecular Advances in Preeclampsia and HELLP Syndrome

Preeclampsia (PE) constitutes one of the principal reasons for maternal and perinatal morbidity and mortality worldwide. The circumstance typically implicates formerly healthful normotensive women, after 20 weeks of gestation, typically withinside the third trimester, without regarded threat elements or past deliveries. PE can be further complicated with hemolysis and thrombocytopenia, leading to the emergence of HELLP syndrome (Hemolysis, Elevated Liver enzymes, Low platelets). Both conditions are classified as hypertensive diseases of pregnancy (HDP), and their pathogenesis has been linked to an excessive maternal inflammatory response, accompanied by enhanced endothelial activation. Several studies have found that in pregnancies affected by PE/HELLP, von Willebrand factor (vWF) antigen levels (vWF:Ag) are significantly elevated, while its cleaving protease (ADAMTS-13, A Disintegrin-like and Metalloprotease with Thrombospondin type 1 motif, member 13) activity is normal to decreased. Furthermore, the higher urine excretion of the terminal complement complex C5b-9, as well as its greater deposition in the placental surface in preeclamptic women, imply that the utero-placental unit’s distinctive deficits are intimately tied to disproportionate complement activation. The goal of this updated evaluation is to provide the most up-to-date molecular advances in the pathophysiology of PE/HELLP syndromes. Recent medical data on vWF:Ag levels in patients with PE, ADAMTS-13, and dysregulation of the complement system, are highlighted and evaluated. Furthermore, we discuss the relationship between those entities and the progression of the disease, as well as their significance in the diagnostic process. Finally, considering the difficulties in analyzing and controlling those symptoms in pregnant women, we can provide a current diagnostic and therapeutic algorithm.

Complement activation and regulation in preeclampsia and hemolysis, elevated liver enzymes, and low platelet count syndrome

The complement system is critical to human health owing to its central role in host defense and innate immunity. During pregnancy, the complement system must be appropriately regulated to allow for immunologic tolerance to the developing fetus and placenta. Although some degree of complement activation can be seen in normal pregnancy, the fetus seems to be protected in part through the placental expression of complement regulatory proteins, which inhibit complement activation at different steps along the complement activation cascade. In women who develop preeclampsia and hemolysis, elevated liver enzymes, and low platelet count syndrome, there is a shift toward increased complement activation and decreased complement regulation. There is an increase in placental deposition of C5b-9, which is the terminal effector of classical, lectin, and alternative complement pathways. C5b-9 deposition stimulates trophoblasts to secrete soluble fms-like tyrosine kinase-1, which sequesters vascular endothelial growth factor and placental growth factor. Pathogenic mutations or deletions in complement regulatory genes, which predispose to increased complement activation, have been detected in women with preeclampsia and hemolysis, elevated liver enzymes, and low platelet count syndrome. Before the disease, biomarkers of alternative complement pathway activation are increased; during active disease, biomarkers of terminal complement pathway activation are increased. Urinary excretion of C5b-9 is associated with preeclampsia with severe features and distinguishes it from other hypertensive disorders of pregnancy. Taken together, existing data link preeclampsia and hemolysis, elevated liver enzymes, and low platelet count syndrome with increased activation of the terminal complement pathway that, in some cases, may be influenced by genetic alterations in complement regulators. These findings suggest that the inhibition of the terminal complement pathway, possibly through C5 blockade, may be an effective strategy to treat preeclampsia and hemolysis, elevated liver enzymes, and low platelet count syndrome, but this strategy warrants further evaluation in clinical trials.

Neuropathophysiology of preeclampsia and eclampsia: A review of cerebral hemodynamic principles in hypertensive disorders of pregnancy

Preeclampsia and eclampsia are hypertensive disorders of pregnancy associated with abnormal placental vascular development. The systemic angiogenic imbalance, endothelial dysfunction and proinflammatory state caused by abnormal placental development results in abnormalities in renal, hepatic, pulmonary and neurologic function. Neurosensory symptoms related to pregnancy induced hypertension (PIH), the most devastating of which are intracranial hemorrhage and seizure, are among the leading causes of maternal and perinatal morbidity and mortality globally, yet risk stratification strategies and targeted therapies remain elusive. Current treatment for preeclampsia with severe features is limited to delivery, antihypertensive therapy, and magnesium sulfate seizure prophylaxis. Magnesium sulfate reduces seizure rates among severe preeclamptics, but predisposes patients to weakness, uterine atony, pulmonary edema and respiratory depression. Therefore, this drug should ideally be administered only to the subset of preeclamptics who are at increased risk for neurologic complications. While there are no objective methods validated to predict eclampsia, we hypothesize that measurement of optic nerve sheath diameters, optic disc height and middle cerebral artery transcranial doppler resistance indices may be useful in identifying subclinical cerebral edema, potentially allowing us to recognize those patients at highest risk for seizures. This summary of the current literature provides an initial framework for developing more sophisticated and noninvasive methods for identifying, monitoring and treating parturients who are at highest risk for neurologic complications from preeclampsia.

Mechanisms of Key Innate Immune Cells in Early- and Late-Onset Preeclampsia

Preeclampsia is a complex cardiovascular disorder of pregnancy with underlying multifactorial pathogeneses; however, its etiology is not fully understood. It is characterized by the new onset of maternal hypertension after 20 weeks of gestation, accompanied by proteinuria, maternal organ damage, and/or uteroplacental dysfunction. Preeclampsia can be subdivided into early- and late-onset phenotypes (EOPE and LOPE), diagnosed before 34 weeks or from 34 weeks of gestation, respectively. Impaired placental development in early pregnancy and subsequent growth restriction is often associated with EOPE, while LOPE is associated with maternal endothelial dysfunction. The innate immune system plays an essential role in normal progression of physiological pregnancy and fetal development. However, inappropriate or excessive activation of this system can lead to placental dysfunction or poor maternal vascular adaptation and contribute to the development of preeclampsia. This review aims to comprehensively outline the mechanisms of key innate immune cells including macrophages, neutrophils, natural killer (NK) cells, and innate B1 cells, in normal physiological pregnancy, EOPE and LOPE. The roles of the complement system, syncytiotrophoblast extracellular vesicles and mesenchymal stem cells (MSCs) are also discussed in the context of innate immune system regulation and preeclampsia. The outlined molecular mechanisms, which represent potential therapeutic targets, and associated emerging treatments, are evaluated as treatments for preeclampsia. Therefore, by addressing the current understanding of innate immunity in the pathogenesis of EOPE and LOPE, this review will contribute to the body of research that could lead to the development of better diagnosis, prevention, and treatment strategies. Importantly, it will delineate the differences in the mechanisms of the innate immune system in two different types of preeclampsia, which is necessary for a more personalized approach to the monitoring and treatment of affected women.

Complement inhibitor Crry expression in mouse placenta is essential for maintaining normal blood pressure and fetal growth

Many circumstantial evidences from human and animal studies suggest that complement cascade dysregulation may play an important role in pregnancy associated complications including preeclampsia. Deletion of rodent specific complement inhibitor gene, Complement Receptor 1-related Gene/Protein y (Crry) produces embryonic lethal phenotype due to complement activation. It is not clear if decreased expression of Crry during pregnancy produces hypertensive phenotype. We downregulated Crry in placenta by injecting inducible lentivialshRNA vectors into uterine horn of pregnant C57BL/6 mice at the time of blastocyst hatching. Placenta specific downregulation of Crry without significant loss of embryos was achieved upon induction of shRNA using an optimal doxycycline dose at mid gestation. Crry downregulation resulted in placental complement deposition. Late-gestation measurements showed that fetal weights were reduced and blood pressure increased in pregnant mice upon downregulation of Crry suggesting a critical role for Crry in fetal growth and blood pressure regulation.

Update on pregnancy complications in systemic lupus erythematosus

PURPOSE OF REVIEW

This review summarizes recent research in the field of systemic lupus erythematosus (SLE) and pregnancy with focus on clinical and biochemical predictors of adverse pregnancy outcomes (APOs), accumulating evidence for the safety and efficacy of hydroxychloroquine (HCQ) in pregnancy, and the importance of preconception counseling.

RECENT FINDINGS

Ongoing research from PROMISSE investigators (Predictors of Pregnancy Outcome: Biomarkers in Antiphospholipid Antibody Syndrome and Systemic Lupus Erythematosus) adds to the understanding of risk factors for APOs in SLE pregnancies, including aberrant complement activation, incomplete downregulation of lupus-associated transcription factors, and lower socioeconomic status. Evidence supporting numerous advantages for continuing HCQ in pregnancy, as well as support for low-dose aspirin in preeclampsia prevention is reviewed. Practice gaps exist among rheumatologists in ensuring effective contraception when women of childbearing age are undergoing therapy with potentially fetotoxic medications. The publication of organizational guidelines provides evidence-based recommendations on lupus pregnancy management.

SUMMARY

Outcomes of lupus pregnancies continue to improve with understanding of risk factors that predict APOs as well as improvements in disease management. Rheumatologists caring for women with SLE should be familiar with the most up-to-date research in order to optimize pregnancy outcomes in this population.

Bioinformatics identification of potential genes and pathways in preeclampsia based on functional gene set enrichment analyses

Preeclampsia is a complication of pregnancy characterized by new-onset hypertension and proteinuria of gestation, with serious consequences for mother and infant. Although a vast amount of research has been performed on the pathogenesis of preeclampsia, the underlying mechanisms of this multisystemic disease have remained to be fully elucidated. Data were retrieved from Gene Expression Omnibus database GSE40182 dataset. After data preprocessing, differentially expressed genes of placental cells cultured in vitro from preeclampsia and normal pregnancy were determined and subjected to Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis to identify the associated pathways. Furthermore, functional principal component analysis (FPCA) was used to calculate the corresponding F-value of each gene. In order to further study the key signaling pathways of preeclampsia, an elastic-net regression model and the Mann-Whitney U (MWU) test were used to estimate the weight of the signaling pathways. Finally, a co-expression network was generated and hub genes were identified based on the topological features. A total of 134 pathways with a role in preeclampsia were identified. The gene expression data of placenta cells cultured in vitro for different durations were determined and F-values of genes were estimated using the FPCA model. The top 1,000 genes were identified as the differentially expressed genes and subjected to further analysis by elastic-net regression and MWU test. Two key signaling pathways were different between the preeclampsia and control groups, namely hsa05142 Chagas disease and hsa05204 Chemical carcinogenesis. Among the genes involved in these two key pathways, 13 hub genes were identified from the co-expression network. Clustering analysis demonstrated that depending on these hub genes, it was possible to divide the sample into four distinct groups based on different incubation time. The top 3 candidates were Toll-like receptor 2 (TLR2), glutathione S-transferase omega 1 (GSTO1) and mitogen-activated protein kinase 13 (MAPK13). TLR2 and associated pathways are known to be closely associated with preeclampsia, indirectly demonstrating the applicability of the analytic process applied. However, the role of GSTO1 and MAPK13 in preeclampsia has remained poorly investigated, and elucidation thereof may be a worthwhile endeavor. The present study may provide a basis for exploring potential novel genes and pathways as therapeutic targets for preeclampsia.

The role of the complement system in HIV infection and preeclampsia

BACKGROUND

The complement system is a key component of the innate immune system that plays a vital role in host defense, maintains homeostasis and acts as a mediator of the adaptive immune response. The complement system could possibly play a role in the pathogenesis of HIV infection and preeclampsia (PE), both of which represent major causes of maternal death in South Africa.

RECENT FINDINGS

The relationship between PE and HIV infection is unclear as PE represents an exaggerated immune response, while HIV infection is associated with a decline in immune activity. Although the complement system works to clear and neutralize HIV, it could also enhance the infectivity of HIV by various other mechanisms. It has been suggested that the dysregulation of the complement system is associated with the development of PE.

CONCLUSION

There is currently a paucity of information on the combined effect of the complement system in HIV-associated PE. This review highlights the role of the complement system in the duality of HIV infection and PE and provides new insights into this relationship whilst also elucidating potential therapeutic targets.

The Immunogenetic Conundrum of Preeclampsia

Pregnancy is an immunological challenge to the mother. The fetal tissues including the placenta must be protected from activation of the maternal immune system. On the other hand, the placental tissue sheds into the maternal circulation and must be adequately identified and phagocytized by the maternal immune system. During a healthy pregnancy, numerous immunosuppressive processes take place that allow the allograft fetus to thrive under exposure to humoral and cellular components of the maternal immune system. Breakdown of immune tolerance may result in sterile inflammation and cause adverse pregnancy outcomes such as preeclampsia, a vascular disease of the pregnancy with unpredictable course and symptoms from several organs. Immunological incompatibility between mother and fetus is strongly indicated in preeclampsia. Recently, genetic factors linking immunological pathways to predisposition to preeclampsia have been identified. In this mini-review genetic variation in immunological factors are discussed in the context of preeclampsia. Specifically, we explore immunogenetic and immunomodulary mechanisms contributing to loss of tolerance, inflammation, and autoimmunity in preeclampsia.

Complement activation predicts adverse pregnancy outcome in patients with systemic lupus erythematosus and/or antiphospholipid antibodies

OBJECTIVE

Studies in mouse models implicate complement activation as a causative factor in adverse pregnancy outcomes (APOs). We investigated whether activation of complement early in pregnancy predicts APOs in women with systemic lupus erythematosus (SLE) and/or antiphospholipid (aPL) antibodies.

METHODS

The PROMISSE Study enrolled pregnant women with SLE and/or aPL antibodies (n=487) and pregnant healthy controls (n=204) at <12 weeks gestation and evaluated them monthly. APOs were: fetal/neonatal death, preterm delivery <36 weeks because of placental insufficiency or preeclampsia and/or growth restriction <5th percentile. Complement activation products were measured on serial blood samples obtained at each monthly visit.

RESULTS

APO occurred in 20.5% of SLE and/or aPL pregnancies. As early as 12-15 weeks, levels of Bb and sC5b-9 were significantly higher in patients with APOs and remained elevated through 31 weeks compared with those with normal outcomes. Moreover, Bb and sC5b-9 were significantly higher in patients with SLE and/or aPL without APOs compared with healthy controls. In logistic regression analyses, Bb and sC5b-9 at 12-15 weeks remained significantly associated with APO (OR_adj=1.41 per SD increase; 95% CI 1.06 to 1.89; P=0.019 and OR_adj=1.37 per SD increase; 95% CI 1.05 to 1.80; P=0.022, respectively) after controlling for demographic and clinical risk factors for APOs in PROMISSE. When analyses were restricted to patients with aPL (n=161), associations between Bb at 12-15 weeks and APOs became stronger (OR_adj=2.01 per SD increase; 95% CI 1.16 to 3.49; P=0.013).

CONCLUSION

In pregnant patients with SLE and/or aPL, increased Bb and sC5b-9 detectable early in pregnancy are strongly predictive of APOs and support activation of complement, particularly the alternative pathway, as a contributor to APOs.

Immunological Tolerance, Pregnancy, and Preeclampsia: The Roles of Semen Microbes and the Father

Although it is widely considered, in many cases, to involve two separable stages (poor placentation followed by oxidative stress/inflammation), the precise originating causes of preeclampsia (PE) remain elusive. We have previously brought together some of the considerable evidence that a (dormant) microbial component is commonly a significant part of its etiology. However, apart from recognizing, consistent with this view, that the many inflammatory markers of PE are also increased in infection, we had little to say about immunity, whether innate or adaptive. In addition, we focused on the gut, oral and female urinary tract microbiomes as the main sources of the infection. We here marshall further evidence for an infectious component in PE, focusing on the immunological tolerance characteristic of pregnancy, and the well-established fact that increased exposure to the father's semen assists this immunological tolerance. As well as these benefits, however, semen is not sterile, microbial tolerance mechanisms may exist, and we also review the evidence that semen may be responsible for inoculating the developing conceptus (and maybe the placenta) with microbes, not all of which are benign. It is suggested that when they are not, this may be a significant cause of PE. A variety of epidemiological and other evidence is entirely consistent with this, not least correlations between semen infection, infertility and PE. Our view also leads to a series of other, testable predictions. Overall, we argue for a significant paternal role in the development of PE through microbial infection of the mother via insemination.

Adrenomedullin2 (ADM2)/Intermedin (IMD): A Potential Role in the Pathophysiology of Preeclampsia

CONTEXT

It is not known whether decreases in trophoblast invasion promoting the peptide, adrenomedullin2 (ADM2) system is associated with preeclampsia (PreE).

OBJECTIVE

The objective of the study was to assess the changes in ADM2 levels in plasma, placenta, and amniotic fluid (AF) and its receptor components in placenta from PreE pregnancy compared with the age-matched normal and study the effect of ADM2 on the synthesis of nitric oxide (NO), endothelial nitric oxide synthase (eNOS), and matrix-metalloproteinase (MMP)-2 and MMP-9 in trophoblast cells.

RESULTS

PreE is associated with a decreased expression of ADM2 in plasma and placenta (P < .05); ADM2 interacts with a seven-transmembrane G protein-coupled receptor, calcitonin receptor-like receptor (CRLR) in HTR-8/SVneo cells; placental expression of ADM2/CRLR complex is lower in PreE; mRNA for CRLR and receptor activity-modifying protein-3 are lower, whereas receptor activity-modifying protein-2 is higher in the PreE placenta (P < .05); ADM2 levels in the second trimester are lower in the AF from pregnant women who develop PreE later in gestation (P < .05); ADM2 is localized to the epithelium of the amnion and the ectoderm and mesoderm of the chorion in term fetal membranes; ADM2 increases NO production, eNOS, and MMP2/9-immunoreactivity, whereas ADM2 knockdown inhibits the expression of eNOS and MMP2/9 mRNA and S-nitrosylation in HTR-8/SVneo cells; and ADM2-induced increases in MMP2/9 activity is inhibited by L-nitro-arginine methyl ester in HTR-8SV/neo cells.

CONCLUSION

Decreases in the ADM2 system in PreE at term, in AF from pregnant women during the second trimester who develop PreE later in gestation, and ADM2-induced increases in the NO and MMP-2/9 levels in trophoblast cells suggest a potential role for ADM2 via the NO-MMP system in the pathophysiology of PreE.

Impaired Vasodilatory Responses of Omental Arteries to CGRP Family Peptides in Pregnancies Complicated by Fetal Growth Restriction

RATIONALE

Calcitonin gene-related peptide (CGRP), adrenomedullin (ADM), and adrenomedullin2 (ADM2)/intermedin are potent vasorelaxant peptides considered to play a role in the adaptive mechanisms in rat pregnancy through increased vasodilation in mesenteric and uterine artery.

OBJECTIVE

This study was designed to demonstrate the response of omental arteries (OA) to vasoactive peptides CGRP, ADM, and ADM2 in pregnancy complications such as fetal growth restriction (FGR), and assess the changes in the expression of their receptor components in segments of OA from FGR pregnancy compared to the control.

FINDINGS

The findings for this study are: 1) relaxation responses of OA were higher for bradykinin (78.55 ± 3.91 vs 52.67 ± 2.19; P < .05) in pregnancy with FGR compared to the normal, 2) relaxation response of OA segments to CGRP was similar with no change in the expression of G-protein couple receptor-calcitonin receptor-like receptor complex in normal healthy pregnancy and pregnancy complicated by FGR, 3) maximal relaxation response of OA were significantly (P < .05) lower for both ADM (18.2 ± 6.7 vs 38 ± 2.5) and ADM2 (26.9 ± 6.7 vs 48 ± 2.6) along with decreases in their respective ligand-receptor complex in FGR compared to the normal pregnancies, 4) expression of calcitonin receptor-like receptor mRNA was higher but its immunoreactivity was lower in OA from FGR pregnancy compared to the normal, and 5) mRNA and protein levels of RAMP1, RAMP2, and RAMP3 were lower in OA isolated from FGR pregnancies compared to the normal.

CONCLUSION

The current study demonstrates that FGR is associated with an increase in the sensitivity of OA to bradykinin and decreased sensitivity for ADM and ADM2 ligand-receptor system with no change in the response for CGRP compared to the normal healthy pregnancy, and suggests a potential role for ADM and ADM2 in the pathophysiology of maternal vasculature in FGR pregnancy.