Causes of recurrent miscarriage after spontaneous pregnancy and after in vitro fertilization

Prognostic model on pregnancy outcomes for women with recurrent spontaneous abortions treated with cyclosporin A: A single-institution experience

BACKGROUND

This study aimed to identify prognostic factors for pregnancy outcomes and construct a prognostic model for pregnancy outcomes in women with Recurrent Spontaneous Abortions (RSA) treated with cyclosporin A.

METHODS

A total of 154 RSA patients treated with cyclosporin A between October 2016 and October 2018 were retrospectively recruited. Multivariate logistic regression was applied to identify the prognostic factors for pregnancy success in RSA women treated with cyclosporin A. The Receiver Operating Characteristic (ROC) curve was applied to construct prognostic value, and the prognostic performance was assessed using area under the ROC.

RESULTS

After adjusting potential confounding factors, the authors noted increased age (OR = 0.771; 95 % CI 0.693‒0.858; p < 0.001) and positive antinuclear antibodies (OR = 0.204; 95 % CI 0.079‒0.526; p = 0.001) were associated with a reduced incidence of pregnancy success, while positive anti-β2 glycoprotein-I-antibody (OR = 21.941; 95 % CI 1.176‒409.281; p = 0.039) was associated with an increased incidence of pregnancy success after treated with cyclosporin A. The AUC of combining these variables for predicting pregnancy failure was 0.809 (95 % CI 0.735‒0.880).

CONCLUSIONS

This study systematically identified the prognostic factors for pregnancy success in women treated with cyclosporin A, and the constructed prognostic model based on these factors with relatively higher prognostic value. Further large-scale prospective studies should be performed to validate the prognostic value of the constructed model.

Anti-proliferation and apoptosis induced via the mTOR/PGC-1α signaling pathway in trophoblast cells of miscarriage

Miscarriage is a common complication during early pregnancy and affects approximately 10%-15% of all pregnant women. Several studies have reported that the abnormal expression of mitochondrial oxidative stress-related genes might be involved in the occurrence and progression of miscarriage. The present study attempted to uncover the role of peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α) in miscarriage chorionic villous tissue. The hypothesis that PGC-1α is crucial for glycolysis and oxidative phosphorylation during early pregnancy was tested. The results showed that the mRNA and protein levels of PGC-1α were significantly increased in the miscarriage chorionic villous tissues compared with the artificial selective abortion group, and that the expression was regulated by mTOR in knockdown and overexpression of mTOR in HTR8 cell lines. PGC-1α also promoted mitochondrion oxidative phosphorylation but inhibited glycolysis process. In addition, PGC-1α could drive ROS production, reduce mitochondrial membrane potential and block NADPH synthesis, resulting in cell cycle arrest and cell apoptosis, eventually leading to miscarriage. These results suggested that the aberrant expression of PGC-1α is involved in the etiology of early miscarriage, providing new perspectives regarding the mechanisms of miscarriage and a potential therapeutic target for miscarriage.

Pregnancy by Oocyte Donation: Reviewing Fetal-Maternal Risks and Complications

Oocyte donation (OD) has greatly improved over the last three decades, becoming a preferred practice of assisted reproductive technology (ART) for infertile women wishing for motherhood. Through OD, indeed, it has become possible to overcome the physiological limitation due to the ovarian reserve (OR) exhaustion as well as the poor gamete reliability which parallels the increasing age of women. However, despite the great scientific contribution related to the success of OD in the field of infertility, this practice seems to be associated with a higher rate of major risky events during pregnancy as recurrent miscarriage, infections and placental diseases including gestational hypertension, pre-eclampsia and post-partum hemorrhage, as well as several maternal-fetal complications due to gametes manipulation and immune system interaction. Here, we will revisit this questioned topic since a number of studies in the medical literature focus on the successful aspects of the OD procedure in terms of pregnancy rate without, however, neglecting the risks and complications potentially linked to external manipulation or heterologous implantation.

Female reproductive tract microbiome and early miscarriages

Miscarriage is one of the main causes of reproductive loss, which can lead to a number of physical and psychological complications and other long-term consequences. However, the role of vaginal and uterine microbiome in such complications is poorly understood. To review the published data on the function of the female reproductive tract microbiome in the pathogenesis of early miscarriages. The articles published over the past 20 years and deposited in PubMed, Google Academy, Scopus, Elibrary, ResearchGate, and EBSCO databases were analyzed. The review presents new data on the impact of the vaginal and uterine microbiome on the local immunity, including defense against sexually transmitted infections, and its association with other factors of miscarriages. The studies on the microbiome of non-pregnant women with recurrent miscarriages in the anamnesis, patients undergoing IVF, and pregnant women with miscarriages, as well as new directions in the microbiome research are discussed. The majority of studies have demonstrated that the dominant species of the vaginal and uterine microbiome in patients with early miscarriages are non-Lactobacillus bacteria. As many of these bacteria have not previously been detected by cultural studies and their role in obstetric complications is not well defined, further research on the female reproductive tract microbiome, including the microbiome of the cervix uteri, is needed to develop new approaches for the prognosis and prevention of miscarriages.

Research trends and hotspots of recurrent pregnancy loss with thrombophilia: a bibliometric analysis

BACKGROUND

Thrombophilia is a group of disorders that result in a blood hypercoagulable state and induce thrombosis, which was found widely existed in recurrent pregnancy loss (RPL). More and more research about thrombophilia has been conducted but the association between thrombophilia and RPL remains uncertain. Thus, it's necessary to combine relevant literature to find the research hotspots and analyze the internal link between different study points, and then predict the development trend in RPL with thrombophilia.

METHODS

Relevant articles between 1970 and 2022 were obtained from the Web of Science (WoS) database. Software VOSviewer and CiteSpace were used to perform the analysis and conduct visualization of scientific productivity and emerging trends.

RESULTS

Seven hundred twenty-five articles published in recent 30 years by 3205 authors from 1139 organizations and 68 countries were analyzed. 37authors, 38 countries, and 53 organizations published papers ≥5. The United States was the most productive country and Univ Amsterdam was the most productive institution. Journal thrombosis and haemostasis had the most total citations. In keyword and clusters, factor-v-Leiden, inherited thrombophilia, activated protein-c, low-dose aspirin, molecular-weigh heparin, polymorphism had high-frequency focus on its etiology, diagnostics, and therapeutics. The strongest keyword bursts showed the research hotspots changed over time.

CONCLUSIONS

There could be differences in the clinical relevance of different type of thrombophilia, as well as single and multiple thrombophilic factors. Anticoagulation and immunotherapy are currently the main treatment options. More clinical trials and basic research are expected and we should attach more attention to the whole management of in-vitro fertilization in the future.

An Altered Microbiota in the Lower and Upper Female Reproductive Tract of Women with Recurrent Spontaneous Abortion

Recurrent spontaneous abortion (RSA) is a complex multifactorial disease. Recently, the microbiota of the female reproductive tract, as an emerging factor in RSA, has gradually attracted the attention of many clinical researchers. Here, we reported that the microbiota of the lower and upper female reproductive tracts from patients with RSA showed no significant differences in alpha diversity compared to that of controls. Beta diversity was significantly higher in the RSA group than in the control group in the vaginal microbiota (P = 0.036), cervical microbiota (P = 0.010) and microbiota from uterine lavage fluid (P = 0.001). In addition, dramatic decreases in gamma interferon and interleukin-6 cytokine levels were observed in the RSA group. In conclusion, our data suggested altered microbial biodiversity in the vagina, cervix and uterine lavage fluid in the RSA group. Alterations in the microbiota in the uterine cavity could be associated with altered cytokine levels, which might be a risk factor for RSA pathogenesis. Moreover, the microbiota composition differed markedly from the lower genital tract to the uterine cavity, and the microbiota in the uterine cavity also distinctly varied between endometrial tissue and uterine lavage fluid in the RSA group. Hence, sampling with these two methods simultaneously allowed a more comprehensive perspective of microbial colonization in the uterine cavity. IMPORTANCE As an obstacle to pregnancy, recurrent spontaneous abortion (RSA) can be caused by a variety of factors, and a current understanding of the etiology of RSA is still lacking; half of cases have an unknown cause. A substantial fraction of patients show no improvement after treatment. Since the microbiota of the female reproductive tract has been proposed as an emerging factor in RSA patients, further investigation is needed to provide guidance for clinical therapy. In general, this is the first report describing the distinct alterations of the vaginal, cervical, and uterine microbiota in RSA, not just that in the vagina. Furthermore, another major strength of this study derived from the further in-depth investigation and analysis of the characteristics of the microbiota colonizing the upper female genital tract in RSA, which provided a more comprehensive view for investigating the uterine microbiota.

Serial changes in two immune checkpoint receptors and ligands, Tim-3/Gal-9 and PD-1/PD-L1 in peripheral blood prior to miscarriage: Comparison with pregnancies resulting in a live birth

PROBLEM

Immune checkpoints Tim-3/Gal-9 and PD-1/PL-1 are involved in the maintenance of maternal-fetal immune tolerance systematically and locally. This study aimed to compare the serial changes of Tim-3/Gal-9, and PD-1/PL-1 in peripheral blood over a 4-week period after blastocyst transfer, between women who had a live birth and those who miscarried.

METHODS OF STUDY

Serial blood samples were obtained on the day of ET, and 9, 16, 23, and 30 days after ET for the measurement of Tim-3 and PD-1 expressions on various lymphocytes by flow cytometry. Concentrations of serum Gal-9 and PD-L1 were measured by ELISA.

RESULTS

In pregnancies that resulted in a live birth, a significant and sustained increase in the proportion of Tim-3⁺ pNK cells was observed from the 9^th to 30^th days after ET, whilst the concentration of serum PD-L1 was significantly increased on the 23^rd and 30^th days after ET when compared to the day of ET. In pregnancies that later miscarried, none of the parameters were significantly changed across all the time points examined. When comparing the results between the two groups, the proportion of Tim-3⁺ CD56^dim NK cells in the women who had a live birth was significantly higher than that in women who miscarried from the 9^th to 30^th day after ET.

CONCLUSION

A significant and sustained increase in the proportion of Tim-3⁺ pNK cells was observed in pregnancies resulting in a live birth but not in pregnancies resulting in a miscarriage, suggesting the changes may be associated with successful pregnancy outcomes.

The possible role of long non-coding RNAs in recurrent miscarriage

Recurrent miscarriage (RM) is a complicated disease in reproductive medicine that impacts many families. Currently, the etiology of RM is thought to include chromosome abnormalities, reproductive tract malformations, autoimmune dysfunction, infection, and environmental factors. However, the underlying mechanisms of RM remain unknown. At present, research on long non-coding RNAs (lncRNAs) is rapidly emerging and becoming a hot research topic in epigenetic studies. Recent studies revealed that lncRNAs are strongly linked to RM and play a crucial role in epigenetic, cell cycle, cell differentiation regulation, and other life activities. This article mainly reviews the difference in lncRNA expression in patients with RM and regulation of susceptibility, endometrial receptivity, and the maternal-fetal interface. Meanwhile, the correlation between lncRNAs and RM is expounded, which provides new insights for the early diagnosis and treatment of RM.

The New Old CD8+ T Cells in the Immune Paradox of Pregnancy

CD8+ T cells are the most frequent T cell population in the immune cell compartment at the feto-maternal interface. Due to their cytotoxic potential, the presence of CD8+ T cells in the immune privileged pregnant uterus has raised considerable interest. Here, we review our current understanding of CD8+ T cell biology in the uterus of pregnant women and discuss this knowledge in relation to a recently published immune cell Atlas of human decidua. We describe how the expansion of CD8+ T cells with an effector memory phenotype often presenting markers of exhaustion is critical for a successful pregnancy, and host defense towards pathogens. Moreover, we review new evidence on the presence of long-lasting immunological memory to former pregnancies and discuss its impact on prospective pregnancy outcomes. The formation of fetal-specific memory CD8+ T cell subests in the uterus, in particular of tissue resident, and stem cell memory cells requires further investigation, but promises interesting results to come. Advancing the knowledge of CD8+ T cell biology in the pregnant uterus will be pivotal for understanding not only tissue-specific immune tolerance but also the etiology of complications during pregnancy, thus enabling preventive or therapeutic interventions in the future.

Influence of Bushen Tiaochong Cycle Therapy on Th1/Th2 Deviation, Sex Hormone Level, and Pregnancy Outcome of Alloimmune Recurrent Spontaneous Abortion

OBJECTIVE

To analyze the influence of Bushen Tiaochong cycle therapy on Th1/Th2 deviation, sex hormone level, and pregnancy outcome of alloimmune recurrent spontaneous abortion (RSA).

METHODS

From August 2018 to April 2020, 130 patients with alloimmune RSA who met the inclusion criteria were randomly divided into the control group (n = 65) and the study group (n = 65). The former received lymphocyte immunotherapy (LIT), and the latter received Bushen Tiaochong cycle therapy on the basis of LIT. The treatment ended at 12 w of pregnancy. The total score of traditional Chinese medicine (TCM) syndromes, Th1 cytokine (IL-2), Th2 cytokine (IL-10), and related hormones (chorionic gonadotropin (hCG) and progesterone (P)) were compared between the two groups before and after treatment. The positive rate of blocking antibody (BA), pregnancy success rate, and preterm birth rate were counted.

RESULT

After treatment, the total score of TCM syndromes, IL-2 level, and Th1/Th2 ratio in the two groups decreased significantly, while the levels of IL-10, hCG, and P increased significantly, and the study group improved significantly compared with the control group (P < 0.05). The positive rate of BA and pregnancy success rate in the study group were higher than those in the control group (P < 0.05). There was no significant difference in the preterm birth rate between the two groups (P > 0.05).

CONCLUSION

On the basis of routine western medicine treatment, a combined application of Bushen Tiaochong cycle therapy can significantly improve the Th1/Th2 deviation, serum sex hormone level, and pregnancy outcome in patients with alloimmune RSA.

Leave the past behind: women's reproductive history shows no association with blastocysts' euploidy and limited association with live birth rates after euploid embryo transfers

STUDY QUESTION

Is there an association between patients' reproductive history and the mean euploidy rates per biopsied blastocysts (m-ER) or the live birth rates (LBRs) per first single vitrified-warmed euploid blastocyst transfers?

SUMMARY ANSWER

Patients' reproductive history (as annotated during counselling) showed no association with the m-ER, but a lower LBR was reported after euploid blastocyst transfer in women with a history of repeated implantation failure (RIF).

WHAT IS KNOWN ALREADY

Several studies have investigated the association between the m-ER and (i) patients' basal characteristics, (ii) ovarian stimulation strategy and dosage, (iii) culture media and conditions, and (iv) embryo morphology and day of full blastocyst development. Conversely, the expected m-ER due to women's reproductive history (previous live births (LBs), miscarriages, failed IVF cycles and transfers, and lack of euploid blastocysts among prior cohorts of biopsied embryos) still needs investigations. Yet, this information is critical to counsel new patients about a first cycle with preimplantation genetic testing for aneuploidy (PGT-A), but even more so after former adverse outcomes to prevent treatment drop-out.

STUDY DESIGN, SIZE, DURATION

This observational study included all patients undergoing a comprehensive chromosome testing (CCT)-based PGT-A cycle with at least one biopsied blastocyst in the period April 2013-December 2019 at a private IVF clinic (n = 2676 patients undergoing 2676 treatments and producing and 8151 blastocysts). m-ER were investigated according to women's reproductive history of LBs: no/≥1, miscarriages: no/1/>1; failed IVF cycles: no/1/2/>2, and implantation failures after previous transfers: no/1/2/>2. Among the 2676 patients included in this study, 440 (16%) had already undergone PGT-A before the study period; the data from these patients were further clustered according to the presence or absence of euploid embryo(s) in their previous cohort of biopsied blastocysts. The clinical outcomes per first single vitrified-warmed euploid blastocyst transfers (n =1580) were investigated according to the number of patients' previous miscarriages and implantation failures.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The procedures involved in this study included ICSI, blastocyst culture, trophectoderm biopsy without hatching in Day 3, CCT-based PGT-A without reporting segmental and/or putative mitotic (or mosaic) aneuploidies and single vitrified-warmed euploid blastocyst transfer. For statistical analysis, Mann-Whitney U or Kruskal-Wallis tests, as well as linear regressions and generalised linear models among ranges of maternal age at oocyte retrieval were performed to identify significant differences for continuous variables. Fisher's exact tests and multivariate logistic regression analyses were instead used for categorical variables.

MAIN RESULTS AND THE ROLE OF CHANCE

Maternal age at oocyte retrieval was the only variable significantly associated with the m-ER. We defined five clusters (<35 years: 66 ± 31%; 35-37 years: 58 ± 33%; 38-40 years: 43 ± 35%; 40-42 years: 28 ± 34%; and >42 years: 17 ± 31%) and all analyses were conducted among them. The m-ER did not show any association with the number of previous LBs, miscarriages, failed IVF cycles or implantation failures. Among patients who had already undergone PGT-A before the study period, the m-ER did not associate with the absence (or presence) of euploid blastocysts in their former cohort of biopsied embryos. Regarding clinical outcomes of the first single vitrified-warmed euploid blastocyst transfer, the implantation rate was 51%, the miscarriage rate was 14% and the LBR was 44%. This LBR was independent of the number of previous miscarriages, but showed a decreasing trend depending on the number of previous implantation failures, reaching statistical significance when comparing patients with >2 failures and patients with no prior failure (36% versus 47%, P < 0.01; multivariate-OR adjusted for embryo quality and day of full blastocyst development: 0.64, 95% CI 0.48-0.86, P < 0.01). No such differences were shown for previous miscarriage rates.

LIMITATIONS, REASONS FOR CAUTION

The sample size for treatments following a former completed PGT-A cycle should be larger in future studies. The data should be confirmed from a multicentre perspective. The analysis should be performed also in non-PGT cycles and/or including patients who did not produce blastocysts, in order to investigate a putative association between women's reproductive history with outcomes other than euploidy and LBRs.

WIDER IMPLICATIONS OF THE FINDINGS

These data are critical to counsel infertile couples before, during and after a PGT-A cycle, especially to prevent treatment discontinuation due to previous adverse reproductive events. Beyond the 'maternal age effect', the causes of idiopathic recurrent pregnancy loss (RPL) and RIF are likely to be endometrial receptivity and selectivity issues; transferring euploid blastocysts might reduce the risk of a further miscarriage, but more information beyond euploidy are required to improve the prognosis in case of RIF.

STUDY FUNDING/COMPETING INTEREST(S)

No funding was received and there are no competing interests.

TRIAL REGISTRATION NUMBER

N/A.