Allelic imbalance modulates surface expression of the tolerance-inducing HLA-G molecule on primary trophoblast cells.

The HLA-G molecule is expressed on trophoblast cells at the feto-maternal interface, where it interacts with local immune cells, and upholds tolerance against the semi-allogeneic fetus. Aberrant HLA-G expression in the placenta and reduced soluble HLA-G levels are observed in pregnancy complications, partly explained by HLA-G polymorphisms which are associated with differences in the alternative splicing pattern and of the stability of HLA-G mRNA. Of special importance is a 14 bp insertion/deletion polymorphism located in the 3'-untranslated region of the HLA-G gene.

Intravenous immunoglobulin treatment for secondary recurrent miscarriage: a randomised, double-blind, placebo-controlled trial.

Objective: To determine whether infusions with intravenous immunoglobulin (IVIg) during early pregnancy increase live birth rate in women with secondary recurrent miscarriage compared with placebo.

Design: A single-centre, randomised, double-blind, placebo-controlled trial.

Setting: A tertiary centre for recurrent miscarriage in Copenhagen, Denmark.

Terminology for pregnancy loss prior to viability: a consensus statement from the ESHRE early pregnancy special interest group.

Pregnancy loss prior to viability is common and research in the field is extensive. Unfortunately, terminology in the literature is inconsistent. The lack of consensus regarding nomenclature and classification of pregnancy loss prior to viability makes it difficult to compare study results from different centres.

Immunomodulatory treatment with intravenous immunoglobulin and prednisone in patients with recurrent miscarriage and implantation failure after in vitro fertilization/intracytoplasmic sperm injection.

Objective: To assess outcome in terms of live-birth rate after fresh or frozen IVF/intracytoplasmic sperm injection assisted reproductive technology (ART) cycles where immunomodulation was given to patients with recurrent pregnancy loss after prior ART treatments.

Design: Retrospective cohort study.

Setting: Tertiary care university hospital.

Non-visualized pregnancy losses are prognostically important for unexplained recurrent miscarriage.

Study Question: Are non-visualized pregnancy losses (biochemical pregnancy loss and failed pregnancy of unknown location combined) in the reproductive history of women with unexplained recurrent miscarriage (RM) negatively associated with the chance of live birth in a subsequent pregnancy?

Summary Answer: Non-visualized pregnancy losses contribute negatively to the chance for live birth: each non-visualized pregnancy loss confers a relative risk (RR) for live birth of 0.90 (95% CI 0.83; 0.

Research methodology in recurrent pregnancy loss.

The aim of this article is to highlight pitfalls in research methodology that may explain why studies in recurrent pregnancy loss (RPL) often provide very divergent results. It is hoped that insight into this issue may help clinicians decide which published studies are the most valid. It may help researchers to eliminate methodological flaws in future studies, which may hopefully come to some kind of agreement about the usefulness of diagnostic tests and treatments in RPL.

Reproductive immunology.

Much research has been done to investigate why the fetus in most pregnancies, in spite of being semi-allogenic, is not rejected by the immune system. Experiments in transgenic mice have suggested that dysfunctions in both the innate immune system (NK cells) and the adaptive immune system (T-cells and T regulatory cells) result in increased fetal loss rate. Many studies have suggested that women with pathological pregnancies such as recurrent miscarriages have signs of generally exaggerated inflammatory immune responses both before and during pregnancy and signs of breakage of tolerance to autoantigens and fetal antigens.

Maternal homozygocity for a 14 base pair insertion in exon 8 of the HLA-G gene and carriage of HLA class II alleles restricting HY immunity predispose to unexplained secondary recurrent miscarriage and low birth weight in children born to these patients.

Homozygous carriage of a 14 base pair (bp) insertion in exon 8 of the HLA-G gene may be associated with low levels of soluble HLA-G and recurrent miscarriage (RM). We investigated the G14bp insertion(ins)/deletion(del) polymorphism in 339 women with unexplained RM and 125 control women. In all patients and patients with secondary RM after a firstborn boy, 19.

A Danish national cohort study on neonatal outcome in singleton pregnancies with placenta previa.

Objective: To describe the incidence of placenta previa and to assess neonatal morbidity and mortality in pregnancies with placenta previa after adjustment for previous cesarean section, smoking, multiparity, maternal age and in vitro fertilization.

Design: National cohort study.

Setting: Danish national IVF-, birth- and patient registers.

Anti-HY responses in pregnancy disorders.

Problem: Cellular and humoral immune responses against male-specific minor histocompatibility (HY) antigens are important in the pathogenesis of graft-versus-host reactions and can be detected in women who have previously given birth to a boy. However, the importance of these responses for pregnancy outcome is unclear.

Method Of Study: Review of the current knowledge about the impact of anti-HY immunity on pregnancy outcome in terms of risk of miscarriage, placental abruption and low birth weight.

Secondary recurrent miscarriage and H-Y immunity.

Background: Approximately half recurrent miscarriage (RM) cases remain unexplained after standard investigations. Secondary RM (SRM) is, in contrast to primary RM, preceded by a birth, which increases the transfer of fetal cells into the maternal circulation. Mothers of boys are often immunized against male-specific minor histocompatibility (H-Y) antigens, and H-Y immunity can cause graft-versus-host disease after stem-cell transplantation.

Hereditary thrombophilia and recurrent pregnancy loss: a retrospective cohort study of pregnancy outcome and obstetric complications.

Background: The association among hereditary thrombophilia, recurrent pregnancy loss (RPL) and obstetric complications is yet uncertain. The objective of the study was to assess the prognostic value of the factor V Leiden (FVL) and prothrombin (PT) mutations for the subsequent chance of live birth for women with RPL.

Methods: Pregnancy outcome was recorded in a retrospective cohort of 363 women with a minimum of three consecutive pregnancy losses (early miscarriage, late miscarriage or stillbirth/neonatal death) who were not treated with anticoagulation therapy.

H-Y antibody titers are increased in unexplained secondary recurrent miscarriage patients and associated with low male : female ratio in subsequent live births.

Background: The birth of a boy is significantly more common than a girl prior to secondary recurrent miscarriage (SRM) and is associated with a poorer chance of a subsequent live birth. Children born after SRM are more likely to be girls. High-titer antisera specific for male antigens (H-Y) have been shown to arrest development of male bovine embryos efficiently.

The presence of HLA-antibodies in recurrent miscarriage patients is associated with a reduced chance of a live birth.

Anti-paternal HLA-antibodies are considered a harmless phenomenon during most pregnancies, whereas their role in recurrent miscarriage (RM) patients is disputed. In contrast to primary RM, patients with secondary RM have carried a fetus to term pregnancy prior to a series of miscarriages, which increases the chance that allogeneic fetal cells appear in the maternal circulation. This study investigates the frequency of HLA-antibodies in secondary RM, primary RM patients and parous controls and analyzes whether the presence of HLA-antibodies in early pregnancy is associated with pregnancy outcome.

Frequency and impact of obstetric complications prior and subsequent to unexplained secondary recurrent miscarriage.

Background: The chance of a live birth after a diagnosis of secondary recurrent miscarriage (SRM) is reduced in patients who, prior to the miscarriages, gave birth to a boy and carry HLA class II alleles that efficiently present male-specific (H-Y) antigens to the immune system. Information about obstetric complications in births prior and subsequent to the SRM diagnosis is limited. The relations between maternal carriage of H-Y-restricting HLA, fetal sex, obstetric complications and prognosis are unknown.

The impact of anti-HY responses on outcome in current and subsequent pregnancies of patients with recurrent pregnancy losses.

Women pregnant with a male fetus often generate cellular and humoral immune responses against male-specific minor histocompatibility (HY) antigens-however, the importance of these responses for pregnancy outcome is unclear. Epidemiologic studies have shown that the birth of a boy compared with a girl prior to a series of miscarriages significantly reduces the chance of a subsequent live birth and pregnancies with boys have an increased risk of placental abruption. This paper aims to review the current knowledge about the impact of anti-HY immunity on pregnancy outcome in terms of miscarriage and placental abruption.

Study of the structure and impact of human leukocyte antigen (HLA)-G-A, HLA-G-B, and HLA-G-DRB1 haplotypes in families with recurrent miscarriage.

A 14-base pair (bp) long insertion (ins)/deletion (del) polymorphism in exon 8 in the 3'-untranslated region of the human leukocyte antigen (HLA)-G gene is suggested to affect transcription of the gene. Carriage of the G14bp ins is associated with low levels of soluble HLA-G and increases the risk of recurrent miscarriage (RM). Due to existence of strong linkage disequilibrium (LD) in the HLA region, the primary susceptibility genes for RM in the HLA-G region have not yet been identified.

Mannose-binding lectin-2 genotypes and recurrent late pregnancy losses.

Background: Low levels of mannose-binding lectin (MBL) predispose to various infectious and inflammatory disorders and have been reported to be associated with recurrent early miscarriages. Recurrent late pregnancy losses (RLPL) in the second trimester is a rare but devastating syndrome where maternal rather than fetal causes are likely to play a stronger role than in early recurrent miscarriage.

Methods: We identified 75 patients with at least two late losses of pregnancies with apparently normal fetuses between gestational week 14 and 30 among patients with recurrent pregnancy losses referred to our clinic.

Multifactorial etiology of recurrent miscarriage and its scientific and clinical implications.

A considerable proportion of recurrent miscarriage (RM) cases are caused by recurrent chromosomally abnormal conceptions. However, in younger patients and patients with multiple miscarriages, maternal causes seem to dominate. No single biomarker with a high predictive value of maternally caused RM has been identified.

Indications of anti-HY immunity in recurrent placental abruption.

Problem: Placental abruption is a potential life-threatening condition for both the fetus and the mother, being significantly more common in pregnancies with male fetuses. The pathogenesis of placental abruption remains unknown. However, some recent reports point toward a maternal immune response against the fetus as a possible mechanism.

Future directions of failed implantation and recurrent miscarriage research.

Recurrent implantation failure is today the major reason for women completing several IVF/intracytoplasmic sperm injection attempts without having achieved a child, and is probably also the explanation for many cases of unexplained infertility. Most causes of recurrent miscarriage are still poorly elucidated, but from a theoretical point of view recurrent implantation failure and recurrent miscarriage are suggested to have partly overlapping causes. Recent research has indeed documented that both syndromes can be caused by the same embryonic chromosomal abnormalities and the same maternal endocrine, thrombophilic and immunological disturbances.

Androgen priming using aromatase inhibitor and hCG during early-follicular-phase GnRH antagonist down-regulation in modified antagonist protocols.

Background: Temporary exposure of follicles to increased levels of androgens may enhance their sensitivity to FSH. The aim of this study was to increase the intraovarian androgen level using aromatase inhibitors and hCG before controlled ovarian stimulation (COH) and to test this concept clinically.

Methods: In a prospective, non-randomized study, 45 patients were treated in modified antagonist protocols including early-follicular-phase down-regulation and androgen priming before COH.

Evidence-based investigations and treatments of recurrent pregnancy loss.

Purpose Of Review: The majority of investigations and treatments offered to women with recurrent pregnancy loss are not evidence-based. In this review a critical analysis is given of the current management of recurrent pregnancy loss often recommended in meta-analyses and guidelines.

Recent Findings: Our knowledge of genetic, endocrine, thrombophilic and immunological causes of recurrent pregnancy loss has been improved significantly, primarily by the introduction of modern laboratory techniques.

Inflammation and miscarriage.

Most relevant studies in animals and humans indicate that some degree of systemic or uterine inflammation is necessary both for normal implantation and pregnancy. However, if inflammation becomes too excessive it might cause pregnancy complications such as fetal resorption/miscarriage. The main regulator of the correct level of inflammation at the feto-maternal interface seems to be the uterine CD16(-) CD56(bright) natural killer (NK) cells.