Spontaneous Abortions Of Unknown Etiology Research Articles

English

INTRODUCTION: Recurrent spontaneous abortion of unknown etiology provided fundamental insight into process of embryogenesis, and implantation. It is also a frustrating and emotionally charged clinical problem. Hormonal imbalances are important cause of recurrent pregnancy loss, in the 1st trimester as well as in 2ndtrimester. Thyroid diseases are the commonest disorders affecting women of reproductive age group.They constitute the commonest endocrine disorder complicating pregnancy. In women incidence of hypothyroidism diagnosed before pregnancy is 1%. Maternal and fetal complications have been found to be higher in this population. In women incidence of hypothyroidism diagnosed before pregnancy is 1%. Maternal and fetal complications have been found to be higher in this population. OBJECTIVE: We studied the Thyroid profile in patients of recurrent abortion. MATERIALS AND METHODS: 60 non pregnant healthy women with complaints of vaginal bleeding, pelvic pain, tissue discharge up to 8, 16, and 22 weeks with 20 subjects in each group. Details of history, physical findings, laboratory evaluation and medication were noted from their case records and verified. 60 healthy, pregnant women who were at same gestational age and then reached the term and had successful pregnancy outcome, were selected as controls. The controls were not under any regimen and were free from any chronic illness. Elisa method was used for estimation of thyroid hormones. RESULTS: We studied 60 non pregnant healthy women (27±2.6 years) with established diagnosis of recurrent spontaneous abortion. Serum TT3, fT3, TT4, fT4 was found to be significantly low in cases as compared to controls. 21 women out of 60 i.e. 35 % showed overt hypothyroidism. Majority of these cases were showing recurrent pregnancy lost in between 8-16 weeks of gestation when their history was traced. CONCLUSION: Hypothyroidism is frequent cause in recurrent pregnancy loss. Severe maternal hypothyroidism early in gestation is strongly associated with fetal distress and abortion. We suggest evaluation of maternal TSH as a routine test for screening hypothyroidism to potentially improve the pregnancy outcome and maternal well being.

No correlation between pinopode formation and LIF and MMP2 expression in endometrium during implantation window

Implantation depends on two factors - embryo and endometrium. The period of maximal endometrial receptivity is a poorly understood phenomenon. We decided to look at three possible markers of implantation: pinopodes, leukemia inhibitory factor, and matrix metalloproteinase 2 and their correlations. We included in the study 23 idiopathic infertility patients and 21 patients with recurrent spontaneous abortions of unknown etiology. Twenty one fertile patients were also recruited. A biopsy was used for endometrial dating according to the Noyes and Hertig criteria, and assessed for the presence of pinopodes via a scanning electron microscope. Endometria were examined in Real Time-Polymerase Chain Reaction cycles for the mRNA expression of leukemia inhibitory factor (LIF) and matrix metalloproteinase 2 (MMP2). No difference was found in the stage of pinopodes development, nor in the coverage of endometrial surface between the studied groups. The expression level for LIF mRNA was lower in control patients compared to idiopathic infertility and recurrent miscarriage patients. No difference was detected in the expression of MMP2 between all studied groups. No correlation was found between pinopodes development stage and LIF and MMP2 expressions in endometrium. Of the studied factors, LIF and pinopodes show the most promise as potential markers of endometrial receptivity. However, the results achieved suggest that these markers are independent of each other.

Y chromosome microdeletions, sperm DNA fragmentation and sperm oxidative stress as causes of recurrent spontaneous abortion of unknown etiology

The aim of the present study was to evaluate the implication of male factor, in terms of sperm DNA oxidation and fragmentation, and Y chromosome microdeletions in recurrent spontaneous abortion (RSA) of unknown origin in a strictly selected cohort. A prospective cohort study was carried out in a private university-affiliated setting. Three groups, each comprised of 30 males, were compared. The first was formed by healthy and fertile sperm donors (SD) with normal sperm parameters (control group), the second by men presenting severe oligozoospermia (SO) without RSA history, and the third by men from couples who had experienced idiopathic RSA. Frequency of Y chromosome microdeletions and mean sperm DNA fragmentation and oxidation were determined. Y chromosome microdeletions were not detected in any of the males enrolled in the study. Moreover, sperm DNA oxidation measurements were not demonstrated to be relevant to RSA. Interestingly, sperm DNA fragmentation was higher in the SO group than in the RSA and the SD groups, and also higher in the RSA group compared with the SD group, but lacked an adequate predictive power to be employed as a discriminative test of RSA condition. Sperm DNA features and Y chromosome microdeletions do not seem to be related to RSA of unknown origin. Other molecular features of sperm should be studied to determine their possible influence on RSA. Clinicaltrials.gov reference: NCT00447395.

Human genetic selection on the MTHFR 677C>T polymorphism

BackgroundThe prevalence of genotypes of the 677C>T polymorphism for the MTHFR gene varies among humans. In previous studies, we found changes in the genotypic frequencies of this polymorphism in populations of different ages, suggesting that this could be caused by an increase in the intake of folate and multivitamins by women during the periconceptional period. The aim was to analyze changes in the allelic frequencies of this polymorphism in a Spanish population, including samples from spontaneous abortions (SA).MethodsA total of 1305 subjects born in the 20th century were genotyped for the 677C>T polymorphism using allele specific real-time PCR with Taqman® probes. A section of our population (n = 276) born in 1980–1989 was compared with fetal samples (n = 344) from SA of unknown etiology from the same period.ResultsAn increase in the frequency of the T allele (0.38 vs 0.47; p < 0.001) and of the TT genotype (0.14 vs 0.24; p < 0.001) in subjects born in the last quarter of the century was observed. In the 1980–1989 period, the results show that the frequency of the wild type genotype (CC) is about tenfold lower in the SA samples than in the controls (0.03 vs 0.33; p < 0.001) and that the frequency of the TT genotype increases in the controls (0.19 to 0.27) and in the SA samples (0.20 to 0.33 (p < 0.01)); r = 0.98.ConclusionSelection in favor of the T allele has been detected. This selection could be due to the increased fetal viability in early stages of embryonic development, as is deduced by the increase of mutants in both living and SA populations.

IMMUNOLOGICAL RELATIONSHIP BETWEEN THE MOTHER AND THE FETUS

The immunological relationship between the mother and the fetus is a bi-directional communication determined on the one hand by fetal antigen presentation and on the other hand by recognition of and reaction to these antigens by the maternal immune system. There is evidence now that immunological recognition of pregnancy is important for the maintenance of gestation, and that inadequate recognition of fetal antigens might result in failed pregnancy. In contrast to HLA-A and -B Class I genes that are downregulated in human trophoblast cells, nonpolymorphic Class I molecules, e.g., HLA-G Class Ib, are expressed in extravillous cytotrophoblast and also in endothelial cells of fetal vessels in the chorionic villi as well as in amnion cells and amniotic fluid. The trophoblast does not induce transplantation immunity and resists NK- and CTL-mediated lysis in vitro. According to our present knowledge, HLA-G presents antigens for γ/δ T cells and at the same time defends the trophoblast from cytotoxic effector mechanisms. Since polymorphic MHC is absent from the trophoblast, presentation of fetally derived antigens is unlikely to be MHC restricted. γ/δ T cells recognize a distinct group of ligands with a smallerreceptorrepertoire than α/β T cells. Most γ/δ T cells recognize unprocessed foreign antigens without MHC. In the decidua γ/δ TCR-positive cells significantly increase in number and the majority of decidual γ/δ T cells are in an activated form due to recognition of conserved mammalian molecules on the trophoblast. Following recognition of fetally derived antigens, the immune system reacts with the setting in of a wide range of protective mechanisms. Many observations suggest that pregnancy is associated with an altered TH1/TH2 balance. Maternal immune response is biased toward humoral immunity and away from cell-mediated immunity that could be harmful to the fetus. Cytokines of maternal origin act on placental development. On the other hand, antigen expression on the placenta determines maternal cytokine pattern. Normal human pregnancy is characterized by low peripheral NK activity, and increased NK activity seems to play a role in spontaneous abortions of unknown etiology. In early human pregnancy the majority of uterine lymphocytes are CD56 bright granulated NK cells, which do not express CD16 or CD3. In rodents and humans, uterine NK cells are under hormonal control. In early pregnancy they are enriched at sites where fetal trophoblast infiltrates the decidua. The dynamics of the appearance of uterine NK cells suggest that one of the functions of these cells is control of placentation. Another protective mechanism operating in favor of pregnancy is progesterone-dependentimmunomodulation. Due to stimulation by fetally derived antigens, pregnancy lymphocytes develop progesterone receptors and in the presence of progesterone produce a mediator (PIBF) that, through altering the cytokine balance, inhibits NK activity and exerts an antiabortive effect in mice.

Identification of the White Blood Cell Populations Responsible for Th1 Immunity to Trophoblast and the Timing of the Response in Women with Recurrent Pregnancy Loss

Aim: The purpose of this study was to identify the white blood cell populations responsible for Th1 immunity to trophoblast as evidenced in our in vitro assays following trophoblast activation and the timing of this response. Study Design: Peripheral blood mononuclear cells (PBMC) were isolated from 32 nonpregnant women with a history of at least three prior first trimester spontaneous abortions of unknown etiology except their PBMC secreted Th1 embryotoxic cytokines in response to trophoblast stimulation. White blood cell populations were separated from PBMC by magnetic immunobeads and cultured with and without a trophoblast antigen extract. Supernatants from these cultures were added to two cell mouse embryos and after four days of culture assessment of blastocyst development was made to determine the white blood cell population responsible for embryotoxicity. In separate experiments trophoblast-activated PBMC culture supernatants were prepared over seven time points and individual Th1 cytokines (IL-2, INF-γ, TNF-α) were measured by ELISA to determine the timing of the response to trophoblast stimulation. Results: The white blood cell (CD45) populations responsible for embryotoxicity in response to trophoblast were T cells (CD3) and NK (CD56) cells. Levels of IL-2 peaked in the first 24 h of culture followed by TNF-α and IFN-γ levels which peaked at 96 h of culture. Conclusions: Our data demonstrated that the white blood cell populations responsible for embryotoxicity in our in vitro assays, were both T and NK cells. The kinetics of the cytokine response to trophoblast found in our study parallels the time course of a typical Th1 cytokine response. The profile of secreted cytokines support our hypothesis that trophoblast can produce Th1 immunity in some women with recurrent pregnancy loss that have embryotoxic effects in vitro.

Immunopathology of the implantation site utilizing monoclonal antibodies to natural killer cells in women with recurrent pregnancy losses.

Placental lesions of 71 women with documented recurrent spontaneous abortions of unknown etiology were evaluated using immunohistochemical staining. Placental tissue blocks (less than 12 weeks gestation) from prior pregnancy losses were obtained, recut, and analyzed utilizing monoclonal antibody to identify the trophoblast (cytokeratin 8/18) and natural killer (NK) cells (CD57) at the implantation site. The following features were evaluated: trophoblast invasion pattern; syncytium formation; vasculitis and thromboembolism of decidual vessels; decidual inflammation; decidual necrosis; fibrin deposition at the decidual necrosis site; mononuclear-cell infiltration in villi and intervillous space; perivillous fibrin deposition; trophoblast morphology; and quantitation of CD57+ NK cells within the decidual tissue near the implantation site. Controls consisted of 20 healthy women with no history of recurrent pregnancy losses, who had their pregnancies electively terminated. Of the women studied, 29.6% demonstrated elevated CD57+ NK cells at the implantation site (P = 0.030), 54.1% had inadequate cytotrophoblast invasion depth (P = 0.000), 44.1% demonstrated inadequate syncytium formation (P = 0.004), and 33.9% presented thromboembolism in decidual vessels (P = 0.025). Some women with recurrent spontaneous abortions demonstrate abnormal placental lesions at the implantation site. Immunopathologic evaluation of the placental implantation site that terminated in a spontaneous abortion may reveal the immunopathogenesis of previous pregnancy losses.

First-trimester repeated abortion is not associated with activated protein C resistance.

The present study was undertaken to investigate the possible association between activated protein C resistance and first-trimester repeated abortion. Fifty-five consecutive patients with unexplained first-trimester repeated abortion and 50 healthy control women having at least one child but no previous abortion were included. Activated protein C resistance was measured in all subjects and factor V Leiden genotype testing was performed in those individuals with phenotypic activated protein C resistance. One patient with first-trimester repeated abortion and one control subject had phenotypic activated protein C resistance. Genotype analysis confirmed that both subjects were heterozygous for factor V Leiden. Our results indicate that first-trimester repeated abortion is not associated with activated protein C resistance. Factor V Leiden screening in first-trimester repeated abortion is not warranted.

Pregnancy outcome following ultrasound-detected fetal cardiac activity in women with a history of multiple spontaneous abortions.

To determine whether women with two or more previous spontaneous abortions of unknown etiology, by conventional testing criteria, have a different rate of subsequent fetal loss than controls after ultrasonic documentation of fetal cardiac activity. Medical records were reviewed from 185 women with spontaneous abortion of unknown etiology. Of these women, 91.9% were found to have evidence of cellular immunity to trophoblast and were treated with progesterone for immunosuppression. Ultrasound evaluation was obtained at 5-6 weeks' gestation to document fetal cardiac activity. A control group of 63 women was also studied. All women were followed for pregnancy outcome. A total of 248 pregnancies were identified from the 185 study patients with multiple spontaneous abortions. Fetal cardiac activity was visualized by ultrasound in 209 pregnancies from 171 study subjects; of these, the outcomes of 208 pregnancies were known. The rate of spontaneous abortion after ultrasound documentation of fetal cardiac activity was 22.7%. Neither maternal age nor number of previous losses was associated with an increased incidence of spontaneous abortion following documentation of fetal cardiac activity. The rate of spontaneous abortion in the control group after documentation of fetal cardiac activity was 3.3%. These data may help clinicians give couples who have experienced recurrent pregnancy loss a more realistic prognosis for pregnancy success once fetal cardiac activity has been confirmed.

Autoantibodies in women with primary recurrent spontaneous abortion of unknown etiology

A group of 153 women with 3 or more recurrent spontaneous abortions (RSAs) with unknown etiology and 90 normal multigravida controls were evaluated for antibodies to phospholipids and nuclear antigens. We demonstrate that women with recurrent spontaneous abortions showed significantly higher incidence of antibodies to phospholipids than normal multigravida controls. In contrast, the incidence of antibodies to polynucleotides and histones was not different between these two groups. These findings suggest that antiphospholipid antibodies are either epiphenomena or causally related to recurrent spontaneous abortions.

Lymphocyte Immunization Generates Immunosuppressive Factors in Women with Recurrent Abortions

Women with recurrent spontaneous abortions of unknown etiology were treated with injection of their partner's lymphocytes. The effect of lymphocyte immunization is evaluated by various immunological tests. The results demonstrate the appearance of immunosuppressive factors, especially P4 protein, present in normal pregnancy, which inhibits cellular cytotoxicity.

9.3-05 DRw6 in repeated spontaneous abortion of unknown etiology

9.3-05 DRw6 in repeated spontaneous abortion of unknown etiology

Transfusions of leukocyte-rich erythrocyte concentrates: A successful treatment in selected cases of habitual abortion

Forty-nine women who suffered recurrent spontaneous abortion of unknown etiology were studied for cellular reactivity and blocking antibody in one-way mixed lymphocyte culture before and after their receipt of three transfusion of leukocyte-rich erythrocyte concentrates from third-party donors. Those 38 of the 49 women who had no blocking antibody all developed significant blocking activity after the transfusion series. Twenty-five of them have become pregnant since, and only one aborted again. The blocking activity demonstrable in 11 of 49 women was increased after the transfusions. Subsequently five of them became pregnant, and all aborted again. We later found that these five women, who considered themselves to be in perfect health, all had serologic signs of autoimmune disease. We advise against transfusion treatment of women who habitually abort without preceding immunologic investigation, because a population of habitual aborters may contain women with yet undiagnosed autoimmune disease, who would be worse off after blood transfusion. We conclude from our results that a selected population of habitual aborters, that is, those without blocking antibody, benefits from transfusion treatment.

Determinants of immunological responsiveness in recurrent spontaneous abortion.

A defined group of 20 women suffering recurrent spontaneous abortions of unknown etiology was studied for determinants relevant to immune responsiveness. A low prevalence of serum anti-CMV antibodies (35%; cf, 65% in controls)--but not anti-herpes-simplex-virus or Epstein-Barr virus antibodies--was noted. Only two (10%) of these women had lymphocytotoxic antibodies following their repeated pregnancies; low titer anti-sperm antibody was present in two other of these women. Whereas there was no significantly increased sharing of HLA-A or -B antigens within these couples compared with controls, there was an increased incidence of apparent HLA-B antigen homozygosity in the women. These data indicate a degree of immunological nonresponsiveness both to cytomegalovirus and to cell-surface alloantigens in habitually aborting women and, together with MLC data, provide further evidence that immunogenetic events may be relevant to reproductive success.

Major Histocompatibility Complex Antigens, Maternal and Paternal Immune Responses, and Chronic Habitual Abortions in Humans

Women with recurrent consecutive spontaneous abortions of unknown etiology compared with those with recurrent spontaneous abortions of known etiology had a significantly, increased frequency of sharing HLA antigens at the A, B, and D/DR loci with their spouses. This major histocompatibility complex (MHC) homozygosity was generally associated with female (responder) and male (stimulator) hyporeactivity in mixed lymphocyte culture reactions. The results indicate that MHC homozygosity between spouses is associated with postfertilization pregnancy wastage in humans.

Major histocompatibility complex antigens, maternal and paternal immune responses, and chronic habitual abortions in humans

Women with recurrent consecutive spontaneous abortions of unknown etiology compared with those with recurrent spontaneous abortions of known etiology had a significantly increased frequency of sharing HLA antigens at the A, B, and D/DR loci with their spouses. This major histocompatibility complex (MHC) homozygosity was generally associated with female (responder) and male (stimulator) hyporeactivity in mixed lymphocyte culture reactions. The results indicate that MHC homozygosity between spouses is associated with postfertilization pregnancy wastage in humans.

HLA Antigen Studies in Women with Recurrent Gestational Disorders

The frequencies of HLA antigens were determined in an experimental group of women with recurrent gestational disorders mainly expressed as spontaneous abortions of unknown etiology. The estimated antigen frequencies in this group were compared with the antigen frequencies in 158 unrelated persons (79 couples with no record of secondary infertility). A significantly higher frequency of antigen HLA-A9 was found in the experimental group as compared with the controls (corrected P = 0.0015). A greater degree of HLA compatibility was found between each woman from this group and her husband, considering 45 couples, as compared with 79 control couples. These results indicate that gene(s) close to the HLA region may have an influence on the reproductive performance in humans.

A familial chromosome abnormality associated with repeated abortions.

A search for familial visible chromosome markers has been initiated among couples who have lost several children by spontaneous abortion. Because the great majority of genetically unbalanced offspring of translocation heterozygotcs die during intrauterine development, repeated spontaneous abortions of unknown etiology, intermittent with successful normal pregnancies, can suggest a reciprocal translocation in the genome of one of the parents. Among the first ten couples studied, one abnormal karyotype was found in the male of a young couple. His wife had lost two children in the third month of pregnancy and has now an apparently successful pregnancy in advanced stage. The abnormal karyotype contained a chromosome of the 21 to 22 group which had an extra chromatin piece, of undetermined origin, translocated to its short arm. This chromosome was also found in the man’s father.