Unexplained Recurrent Pregnancy Loss Research Articles

Effect of low-dose aspirin on mid-luteal phase uterine Artery blood flow in women with unexplained recurrent pregnancy loss

Objectives: As a possible therapy for recurrent pregnancy loss, this study sought to ascertain if low-dose aspirin was effective in increasing uterine artery blood flow. Study Design: This investigation was structured as a single-arm clinical trial Patients and Methods: All participants were aged 39 years or younger and had no prior or current indications of abnormal glucose tolerance, thyroid dysfunction, hyperprolactinemia, or Antiphospholipid antibody syndrome. Bilateral assessments of the Systolic/Diastolic (S/D) ratio, Resistive Index (RI), and Pulsatility Index (PI) were conducted in the chosen patients in the mid-luteal phase, before to and following a minimum of two weeks of low-dose aspirin administration. Results: The results of this investigation showed significant variation in the S/D and PI prior to and following aspirin administration. There was no discernible shift in RI. The analysis revealed a statistically significant reduction in uterine artery PI after aspirin administration (1.92±0.29) compared to the pre-treatment value (2.22±0.27), with a p-value of 0.0001. Remarkably, the pulsatility indices of the left and right uterine arteries did not significantly differ from one another. Conclusion: For women who have a history of miscarriages, low-dose aspirin can be recommended as an adjuvant therapy as it effectively improves uterine artery blood flow in these patients. However, more well-designed research is required to ascertain whether improved pregnancy outcomes are correlated with improved uterine perfusion. The current study supported the aspirin guideline for women with a history of recurrent miscarriages by showing that aspirin treatment resulted in a reduction in uterine artery PI.

Expression and clinical significance of lncRNA PART1 in patients with unexplained recurrent pregnancy loss

Purpose Previous studies have reported the involvement of long noncoding RNAs (lncRNAs) in reproductive diseases via the regulation of target genes. This study aimed to determine whether lnc-prostate androgen-regulated transcript 1 (lnc-PART1)could be used as a biomarker of unexplained recurrent pregnancy loss (URPL) and a possible predictor of poor pregnancy outcomes in women with URPL. Materials and methods Sixty patients with URPL and 15 healthy women were included in this study. PART1 expression was detected in plasma and endometrial tissues using a quantitative reverse transcription polymerase chain reaction. Logistic regression and receiver operating characteristic curve analyses were performed to analyze the association between PART1 expression and pregnancy outcomes in women with URPL. Results The expression of PART1transcript variant 2 was significantly up-regulated in the endometrial specimens from patients with URPL compared to control tissues. High tissue expression levels of PART1transcript variant 2 were associated with poor pregnancy outcomes in women with URPL, indicating that it could serve as a potential risk factor. Additionally, PART1 could serve as a potential risk factor for adverse pregnancy outcomes in patients with URPL (OR = 4.374; 95% CI = 1.052–18.189; p = .042). Conclusion lncRNA PART1 transcript variant 2 was highly expressed in patients with URPL. Therefore, it is important to conduct in-depth studies on the relationship between PART1 expression and URPL.

High Prevalence of Anti-Prothrombin IgM and IgG Autoantibodies in Women With Unexplained Recurrent Pregnancy Loss.

To investigate the association between anti-prothrombin IgM and IgG antibodies and recurrent pregnancy loss (RPL) in a cohort of Lebanese women, and their impact on pregnancy outcomes. This was a retrospective case-control study involving 207 women with RPL and 179 age-matched multiparous controls. Quantitative sandwich ELISA assayed anti-prothrombin IgM and IgG antibodies. Univariate and multivariate logistic regression were employed to assess the risk imparted by anti-prothrombin antibodies, while ROC analysis was used to determine their sensitivity and specificity. Our study revealed that women with RPL had significantly higher serum levels of anti-prothrombin IgM and IgG than controls. Univariate regression analysis demonstrated that elevated anti-prothrombin IgM (OR = 1.13; 95% CI = 1.07, 1.19; P < 0.001) and IgG (OR = 1.05; 95% CI = 1.03, 1.08; P < 0.001) were associated with increased RPL risk. Multivariate analysis confirmed these findings, indicating that anti-prothrombin IgM (aOR = 1.13; 95% CI = 1.05, 1.20; P < 0.001) and IgG (aOR = 1.08; 95% CI = 1.05, 1.11; P < 0.001) are independent risk factors. ROC analysis yielded an AUC of 0.720 for IgM and 0.649 for IgG, underscoring their predictive value and offering hope for improved risk assessment and management of RPL. Elevated levels of anti-prothrombin IgM and IgG are significantly associated with RPL, suggesting an autoimmune component to pregnancy loss. These findings highlight the importance of screening for these antibodies in women with unexplained RPL to guide management and therapeutic strategies.

Correlation Between Serum Markers and Midluteal Phase Doppler Assessment of Uterine Arterial Blood Flow in Unexplained Recurrent Pregnancy Loss.

This study aimed to determine changes in uterine artery Doppler parameters in unexplained recurrent pregnancy loss (URPL) and to explore serum markers possibly associated with them. This retrospective case-control study included 107 URPL women and 107 control women. The mean pulsatility index (PI), resistive index (RI), and systolic-to-diastolic values for uterine arteries in URPL women were significantly higher than those in the controls (P < 0.05). The cutoff values of PI and RI differentiating the women with URPL from the controls were confirmed by ROC and Youden's index. Given a PI cutoff value of 2.6, the prevalence of URPL was significantly elevated in the high-PI group (74.58%) compared with that in the low-PI group (40.65%, P < 0.0001), with sensitivity and specificity of 63% and 69%, respectively. With an RI cutoff value of 0.86, the prevalence of URPL in the high-RI group (65.28%) was significantly elevated compared with that in the low-RI group (42.25%, P = 0.001), with sensitivity and specificity of 66% and 75%, respectively. The levels of serum D-dimers and anticardiolipin antibody (ACA)-IgM in URPL women were significantly higher than those in the controls. A positive correlation existed between the levels of ACA-IgM and uterine artery RI in URPL women (r = 0.43, P < 0.01). These results indicated that URPL women may be at a relatively high risk of a prothrombotic state, and the increased ACA-IgM deserves attention for its role in the elevated uterine artery Doppler parameters in URPL women.

Doppler Evaluation of Uterine Blood Flow in Patients with Unexplained Recurrent Pregnancy Loss.

This study aimed to analyze uterine artery and spiral artery hemodynamics in patients with unexplained recurrent pregnancy loss (URPL) with varying pregnancy outcomes. 174 pregnant women with URPL and 144 pregnant women without adverse pregnancy histories were enrolled in this retrospective study. Based on pregnancy outcomes, these patients were divided into two groups: normal pregnancy outcomes (URPL-N, n=138) and adverse pregnancy outcomes (URPL-A, n=36). Control group participants were categorized into normal pregnancy outcomes (CON-N, n=129) and adverse pregnancy outcomes (CON-A, n=15). We compared uterine artery and spiral artery hemodynamics during different stages of gestation and the predictive value of these parameters for pregnancy outcomes. URPL-N group had fewer pregnancy losses and lower BMI compared to URPL-A group (P< 0.05). Spiral artery hemodynamics in URPL-N and CON-N groups were lower than those in URPL-A and CON-A groups during the mid-luteal phase, 11-13weeks, 15-17weeks, and 19-21weeks of gestation, respectively. Uterine artery hemodynamics ((Pulsatility index (mPI), resistive index (mRI), and systolic-to-diastolic ratio (mS/D)) in the mid-luteal period were lower in URPL-N group than URPL-A group. Similarly, in CON-N group were lower than CON-A group. The URPL-A and CON-A groups had higher uterine artery and spiral artery hemodynamics when compared to the URPL-N and CON-N groups. Spiral artery hemodynamics exhibited larger areas under the ROC curve compared to uterine artery parameters. Abnormal hemodynamics in these arteries may contribute to URPL and adverse pregnancy outcomes. Spiral artery hemodynamics are more reliable predictors of pregnancy outcomes than uterine artery parameters.

Unexplained Recurrent Pregnancy Loss: Clinical Application of Immunophenotyping.

Recurrent pregnancy loss (RPL) is defined as the failure of two or more pregnancies and affects approximately 5% of couples, often without a clear cause. The etiologies of RPL include factors such as maternal age, endocrine dysfunction, uterine abnormalities, chromosomal abnormalities, thrombophilias, infections, and autoimmune disorders. However, these conditions account for only 50%-60% of RPL cases. Research has explored whether an altered immune system, compared to the physiological state, may be linked to RPL. This review aims to determine whether specific immunophenotypes are associated with unexplained Recurrent Pregnancy Loss (uRPL) and whether targeted therapies addressing specific immunophenotypic alterations can improve pregnancy outcomes. A literature review was conducted using Pubmed/Medline, Scopus, and Embase databases, analyzing data from 95 articles published between 2001 and 2023. The roles of various cells of the immune system (B lymphocytes, T lymphocytes, natural killer cells, macrophages) in different tissues (peripheral blood, menstrual blood) were specifically investigated in women with uRPL. Specific immunophenotypes have been demonstrated to be associated with this condition. However, there is a need to standardize immunophenotyping assays and conduct more trials to stratify RPL risk and improve potential therapeutic strategies.

Association of MTR and MTRR polymorphisms with recurrent pregnancy loss: a case control study.

In light of several epidemiological studies, the etiology of recurrent pregnancy loss is complex. One of the most frequent causes of women experiencing inexplicable recurrent pregnancy loss is maternal thrombophilia. Hence, the association between genetic polymorphisms causing thrombophilia and recurrent pregnancy loss needs to be explored. Is to study the relation of polymorphisms affecting folate pathway mainly, 5-Methytetrahydrofolate-Homocysteine Methyltransferase (MTR A2756G) and 5-Methytetrahydrofolate-Homocysteine MethyltransferaseReductase (MTRR A66G) with recurrent pregnancy loss. It is a case-control study. Four hundred participants were enrolled. Two hundred participants with unexplained recurrent pregnancy loss (case group) and two hundred healthy fertile participants (control group). All participants were screened for (MTR A2756G) and (MTRR A66G). DNA was extracted using salting out method followed by genotyping via Real-time PCR. Mutant homozygous genotype (GG) in MTRR A66G was statistically significantly among RPL group in comparison to controls. (GG vs. AA) had odds ratio and confidence interval of 1.22(1.12-2.23), P = 0.012. (GG) increased the liability 1.2 folds for recurrent pregnancy loss. Mutant homozygous genotype (GG) in MTR A2756G was not correlated with the risk of recurrent pregnancy loss. (GG vs.AA) = (1.13(0.56-2.29)), P = 0.7 CONCLUSION: MTRR A66G increases susceptibly for recurrent pregnancy loss among Egyptian women.

Impact of sperm DNA fragmentation in couples with unexplained recurrent pregnancy loss: A cross-sectional study.

Recurrent pregnancy loss (RPL) has a multifactorial etiology, with a majority of cases remaining unexplained. To account for these unexplained cases, possible male factors are being explored. Conventional semen analysis lacks a qualitative assessment of sperms and information regarding sperm DNA integrity. Sperm DNA fragmentation (SDF) has diagnostic value in unexplained RPL, and it may account for a number of unexplained cases. Hence, we planned a study to explore and evaluate the impact of sperm DNA fragmentation in couples with unexplained recurrent pregnancy losses. Analytical cross-sectional study was conducted at a tertiary-level referral facility in India between August 2021 and July 2023. Participants (n = 70) were divided into two groups-male partners of couples with unexplained RPL (following spontaneous conceptions) (n = 35) and men with at least one previous live birth (spontaneous or following fertility treatments for female factor infertility such as ovulation induction or intrauterine insemination) as controls (n = 35). Neither of the two groups of couples recruited for this study had undergone ART as fertility treatment. Primary outcome assessed was mean DNA fragmentation index (DFI). Secondary outcomes included differences in semen parameters such as sperm concentration, progressive sperm motility and morphology, proportion of men with high (≥30%) and low DFI in the two groups, and the association between various semen parameters and DFI. Univariate logistic regression revealed that sperm DNA fragmentation was higher in men with unexplained RPL (30.0; IQR (interquartile range) 19.0, 46.0) as compared to controls (22.0; IQR 14.0, 30.0) although it was not statistically significant (OR, odds ratio, 1.02; 95% CI 1.0-1.1, p = 0.08). A higher proportion of men with unexplained RPL had DFI ≥30% compared to controls (54.2% vs. 25.7%; OR 3.43 (95% CI 1.2-9.4); p = 0.02). No statistically significant differences were observed in semen volume, sperm concentration, progressive motility, and morphology between the two groups. Sperm DNA fragmentation index also showed a weak but significant inverse relationship with sperm morphology (r = -0.336, p = 0.004). The current study did not show any significant difference in the mean sperm DNA fragmentation levels in male partners of couples with unexplained RPL compared to controls. However, a higher proportion of men with DFI ≥30% were observed in unexplained RPL population when compared to controls.

Intravenous immunoglobulin improves live birth rates in patients with unexplained recurrent pregnancy loss

This real-world study aimed to assess the clinical efficacy and safety of intravenous immunoglobulin (IVIG) in treating unexplained recurrent pregnancy loss (uRPL) patients. A total of 238 patients with uRPL were enrolled in this retrospective study. According to the treatment, patients were assigned into treatment group (n=184, receiving IVIG+low molecular weight heparin [LMWH]) and control group (n=54, only LMWH). The primary outcome was the live birth rates (LBR) after 24 weeks of gestation. In addition, we performed subgroup analyses to assess the LBR in uRPL patients with age (≥30 years or <30 years), body mass index (BMI, 18–24 kg/m2 or ≥24 kg/m2), number of previous pregnancy losses (2 or ≥3), gestational week of first medication, and IVIG medication regimen during pregnancy. The LBR showed a significant increase after IVIG treatment compared to the control group (77.7 % vs. 53.7 %, P=0.001). Multivariable logistic regression indicated that IVIG was associated with increased LBR (aOR=4.383, 95 %CI 2.024–9.489). Besides, we observed a significantly lower incidence of decreased platelet count (1.6 % vs. 7.4 %, P=0.049) in the treatment group. Subgroup analyses showed that IVIG treatment was associated with improved LBR in uRPL patients with age of <30 years (aOR=4.012, 95 %CI 1.428–11.266), previous pregnancy losses ≥3 times (aOR=17.327, 95 %CI 2.525–118.921), and BMI of 18–24 kg/m2 (aOR=8.914, 95 %CI 2.985–26.618). IVIG treatment significantly improves the LBR in uRPL patients. These findings from real-world data provide evidence for the safety and efficacy of IVIG as a viable treatment for uRPL patients in clinical practice.

A nomogram and risk stratification to predict subsequent pregnancy loss in patients with recurrent pregnancy loss.

Could the risk of subsequent pregnancy loss be predicted based on the risk factors of recurrent pregnancy loss (RPL) patients? A nomogram, constructed from independent risk factors identified through multivariate logistic regression, serves as a reliable tool for predicting the likelihood of subsequent pregnancy loss in RPL patients. Approximately 1-3% of fertile couples experience RPL, with over half lacking a clear etiological factor. Assessing the subsequent pregnancy loss rate in RPL patients and identifying high-risk groups for early intervention is essential for pregnancy counseling. Previous prediction models have mainly focused on unexplained RPL, incorporating baseline characteristics such as age and the number of previous pregnancy losses, with limited inclusion of laboratory and ultrasound indicators. The retrospective study involved 3387 RPL patients who initially sought treatment at the Reproductive Immunology Clinic of Renji Hospital, Shanghai Jiao Tong University School of Medicine, between 1 January 2020 and 31 December 2022. Of these, 1153 RPL patients met the inclusion criteria and were included in the analysis. RPL was defined as two or more pregnancy losses (including biochemical pregnancy loss) with the same partner before 28 weeks of gestation. Data encompassing basic demographics, laboratory indicators (autoantibodies, peripheral immunity coagulation, and endocrine factors), uterine and endometrial ultrasound results, and subsequent pregnancy outcomes were collected from enrolled patients through initial questionnaires, post-pregnancy visits fortnightly, medical data retrieval, and telephone follow-up for lost patients. R software was utilized for data cleaning, dividing the data into a training cohort (n = 808) and a validation cohort (n = 345) in a 7:3 ratio according to pregnancy success and pregnancy loss. Independent predictors were identified through multivariate logistic regression. A nomogram was developed, evaluated by 10-fold cross-validation, and compared with the model incorporating solely age and the number of previous pregnancy losses. The constructed nomogram was evaluated using the AUC, calibration curve, decision curve analysis (DCA), and clinical impact curve analysis (CICA). Patients were then categorized into low- and high-risk subgroups. We included age, number of previous pregnancy losses, lupus anticoagulant, anticardiolipin IgM, anti-phosphatidylserine/prothrombin complex IgM, anti-double-stranded DNA antibody, arachidonic acid-induced platelet aggregation, thrombin time and the sum of bilateral uterine artery systolic/diastolic ratios in the nomogram. The AUCs of the nomogram were 0.808 (95% CI: 0.770-0.846) in the training cohort and 0.731 (95% CI: 0.660-0.802) in the validation cohort, respectively. The 10-fold cross-validated AUC ranged from 0.714 to 0.925, with a mean AUC of 0.795 (95% CI: 0.750-0.839). The AUC of the nomogram was superior compared to the model incorporating solely age and the number of previous pregnancy losses. Calibration curves, DCAs, and CICAs showed good concordance and clinical applicability. Significant differences in pregnancy loss rates were observed between the low- and high-risk groups (P < 0.001). This study was retrospective and focused on patients from a single reproductive immunology clinic, lacking external validation data. The potential impact of embryonic chromosomal abnormalities on pregnancy loss could not be excluded, and the administration of medication to all cases impacted the investigation of risk factors for pregnancy loss and the model's predictive efficacy. This study signifies a pioneering effort in developing and validating a risk prediction nomogram for subsequent pregnancy loss in RPL patients to effectively stratify their risk. We have integrated the nomogram into an online web tool for clinical applications. This study was supported by the National Natural Science Foundation of China (82071725). All authors have no competing interests to declare. N/A.

Optimizing evaluation of endometrial receptivity in recurrent pregnancy loss: a preliminary investigation integrating radiomics from multimodal ultrasound via machine learning.

Recurrent pregnancy loss (RPL) frequently links to a prolonged endometrial receptivity (ER) window, leading to the implantation of non-viable embryos. Existing ER assessment methods face challenges in reliability and invasiveness. Radiomics in medical imaging offers a non-invasive solution for ER analysis, but complex, non-linear radiomic-ER relationships in RPL require advanced analysis. Machine learning (ML) provides precision for interpreting these datasets, although research in integrating radiomics with ML for ER evaluation in RPL is limited. To develop and validate an ML model that employs radiomic features derived from multimodal transvaginal ultrasound images, focusing on improving ER evaluation in RPL. This retrospective, controlled study analyzed data from 346 unexplained RPL patients and 369 controls. The participants were divided into training and testing cohorts for model development and accuracy validation, respectively. Radiomic features derived from grayscale (GS) and shear wave elastography (SWE) images, obtained during the window of implantation, underwent a comprehensive five-step selection process. Five ML classifiers, each trained on either radiomic, clinical, or combined datasets, were trained for RPL risk stratification. The model demonstrating the highest performance in identifying RPL patients was selected for further validation using the testing cohort. The interpretability of this optimal model was augmented by applying Shapley additive explanations (SHAP) analysis. Analysis of the training cohort (242 RPL, 258 controls) identified nine key radiomic features associated with RPL risk. The extreme gradient boosting (XGBoost) model, combining radiomic and clinical data, demonstrated superior discriminatory ability. This was evidenced by its area under the curve (AUC) score of 0.871, outperforming other ML classifiers. Validation in the testing cohort of 215 subjects (104 RPL, 111 controls) confirmed its accuracy (AUC: 0.844) and consistency. SHAP analysis identified four endometrial SWE features and two GS features, along with clinical variables like age, SAPI, and VI, as key determinants in RPL risk stratification. Integrating ML with radiomics from multimodal endometrial ultrasound during the WOI effectively identifies RPL patients. The XGBoost model, merging radiomic and clinical data, offers a non-invasive, accurate method for RPL management, significantly enhancing diagnosis and treatment.

Assessment of Vitamin D3 Levels in Cases of Unexplained Recurrent Pregnancy Loss in Assiut

Assessment of Vitamin D3 Levels in Cases of Unexplained Recurrent Pregnancy Loss in Assiut

Common and rare genetic variants predisposing females to unexplained recurrent pregnancy loss

Recurrent pregnancy loss (RPL) is a major reproductive health issue with multifactorial causes, affecting 2.6% of all pregnancies worldwide. Nearly half of the RPL cases lack clinically identifiable causes (e.g., antiphospholipid syndrome, uterine anomalies, and parental chromosomal abnormalities), referred to as unexplained RPL (uRPL). Here, we perform a genome-wide association study focusing on uRPL in 1,728 cases and 24,315 female controls of Japanese ancestry. We detect significant associations in the major histocompatibility complex (MHC) region at 6p21 (lead variant=rs9263738; P = 1.4 × 10−10; odds ratio [OR] = 1.51 [95% CI: 1.33–1.72]; risk allele frequency = 0.871). The MHC associations are fine-mapped to the classical HLA alleles, HLA-C*12:02, HLA-B*52:01, and HLA-DRB1*15:02 (P = 1.1 × 10−10, 1.5 × 10−10, and 1.2 × 10−9, respectively), which constitute a population-specific common long-range haplotype with a protective effect (P = 2.8 × 10−10; OR = 0.65 [95% CI: 0.57–0.75]; haplotype frequency=0.108). Genome-wide copy-number variation (CNV) calling demonstrates rare predicted loss-of-function (pLoF) variants of the cadherin-11 gene (CDH11) conferring the risk of uRPL (P = 1.3 × 10−4; OR = 3.29 [95% CI: 1.78–5.76]). Our study highlights the importance of reproductive immunology and rare variants in the uRPL etiology.

Altered N6-methyladenosine methylation level in spermatozoa messenger RNA of the male partners is related to unexplained recurrent pregnancy loss.

Understanding the pathogenesis of unexplained recurrent pregnancy loss is paramount for advancing effective treatments. Various biological processes, including spermatogenesis and embryo development, are tightly regulated by N6-methyladenosine modifications. However, few studies have focused on the impact of sperm N6-methyladenosine modifications on embryonic development. Therefore, we aimed to study altered N6-methyladenosine-mediated messenger RNA methylation modifications in the spermatozoa of male partners from couples experiencing unexplained recurrent pregnancy loss, to identify potential diagnostic markers and explore their potential molecular mechanisms in pregnancy loss and embryogenesis. Methylated RNA immunoprecipitation (MeRIP) sequencing and RNA sequencing were conducted on the spermatozoa of men from couples in the 'unexplained recurrent pregnancy loss' group (n=6), and the fertility control group (n=6). To identify the role of the detected key genes, zebrafish model embryos were studied, and multi-omics (transcriptomics, proteomics, and metabolomics) analyses helped to explore the molecular mechanism of abnormal embryogenesis. Comparing unexplained recurrent pregnancy loss with the fertility control group, 217 N6-methyladenosine peaks were significantly upregulated, and 40 were downregulated in the spermatozoa. The combined analyses of spermatozoa-methylated RNA immunoprecipitation sequencing and RNA sequencing indicated that N6-methyladenosine methylation and the expression of SEMA5A, MT-ATP6, ZNF662, and KDM4C were significantly different. In zebrafish embryos, the altered expression of the four genes increased embryonic mortality and malformations by disturbing several key signaling pathways and zygotic genome activation. This study highlights the paternal epigenome, which could be one of the reasons for faulty embryogenesis leading to pregnancy loss. The N6-methyladenosine modification, the most prevalent RNA modification, contributes to the exploration and understanding of the paternal epigenome in the maintenance of pregnancy and fetal growth and development. The four genes identified in this study may serve as potential diagnostic markers and elucidate novel molecular mechanisms of embryogenesis.

P-419 Relevance of intravenous immunoglobulins in patients with unexplained recurrent pregnancy loss that occurred at the same gestational weeks every time

Abstract Study question Are intravenous immunoglobulins (IVIG) effective for the selected patients who experienced unexplained recurrent pregnancy loss (RPL) that occurred at the same gestational weeks every time? Summary answer IVIG before and after the gestational week-limit (GWL), where miscarriage occurred at the same gestational weeks every time, may improve pregnancy outcomes in RPL patients. What is known already There is no established treatment for patients with unexplained RPL. Some investigators have indicated that IVIG may exhibit therapeutic efficacy in women with unexplained RPL. Since it has been reported that live birth rate significantly increased in women with four or more RPL of unexplained etiology, who received a high dose IVIG at 4-5 weeks of gestation in 2022, ESHRE Guideline Group on RPL (2022) has changed the recommendation to the following: the use of repeated and high doses of IVIG very early in pregnancy may improve live birth rate in women with four or more unexplained RPL. Study design, size, duration We performed a retrospective study between September 2013 to March 2023 in two fertility centers. We included 164 patients in the study who experienced 2 or more miscarriages between 5 and 21 weeks of gestation that occurred at the same gestational weeks every time, who had all negative results for our routine RPL work up and still unsuccessful result after treating these conditions, and whose products of conceptus (POC) revealed at least one normal karyotype. Participants/materials, setting, methods IVIG (Venoglobulin IH 5%, Japan Blood Products Organization, 0.4g/kg) injection was performed twice before and after 1 week of GWL. We divided 164 patients into IVIG group and non-IVIG group by their own choice. The primary outcome was live birth rate, and the secondary outcome was modified live birth rate excluding pregnancies with abnormal fetal karyotype, maternal and neonatal complications. All participants provided written informed consent, and Institutional Review Board approval was obtained. Main results and the role of chance IVIG group (n = 116) and non-IVIG group (n = 48) showed no significant differences in the background of patients on BMI (20.3±3.7 and 21.1±2.8), age (37.4±4.2 and 36.7±3.2) and Childbirth history (20.7% and 23.0%), respectively (average±SD), except for the history of past miscarriages. Average numbers of previous miscarriages on IVIG group and non-IVIG group were 3.2±1.3 and 2.5±0.8 (p &amp;lt; 0.001), respectively. After multivariate analysis for BMI, age, Childbirth history and previous miscarriages, live birth rate of IVIG group (70.7%, 82/116) was significantly higher than that of non-IVIG group (60.4%, 29/48; Odds ratio 3.40, 95% CI: 1.49-7.74, p = 0.003). Similarly, modified live birth rate of IVIG group (73.9%, 82/111) was significantly higher than that of non-IVIG group (63.0%, 29/46; Odds ratio 3.40, 95% CI: 1.49-7.74, p = 0.003). Treatment outcomes when IVIG was used for each number of previous miscarriages, the modified birth rate was 88.3% for two times miscarriages, 77.0% for three times, and 57.1% for four or more miscarriages. Maternal complications were observed in 2 cases in IVIG group (chest tightness, obstetric critical bleeding). There were no significant differences in the birth weight, gestational weeks, preterm birth, or fetal growth restriction of newborns between two groups. Limitations, reasons for caution Since retrospective nature and we did not perform POC tests for all patients whose pregnancies had ended in miscarriage, we could not assert the effectiveness of IVIG. We need to conduct randomized controlled trial using placebo group to demonstrate the IVIG efficacy before and after the GWL using euploid blastocysts. Wider implications of the findings IVIG before and after the GWL adjusted for each patient may improve pregnancy outcomes in RPL patients. Although IVIG is expensive, the current method requires only two IVIG injections, that may be acceptable for much more patients who want to avoid miscarriages and who didn’t use IVIG for economic reasons. Trial registration number NA

P-443 An association between olfaction and unexplained recurrent pregnancy loss

Abstract Study question Is there a male body-odor associated with unexplained recurrent pregnancy loss (uRPL)? Summary answer The body-odor of men from uRPL couples may have different chemical composition than control men. What is known already Recurrent pregnancy loss is defined as 2-3 consecutive pregnancy losses, affecting about 1% of all couples, and in about half of them, the reason for the pregnancy losses in unexplained (uRPL). In our previously published study, we found that women who experienced uRPL have altered perceptual and brain responses to men’s body-odors in comparison to control women. This suggests a possible link between uRPL and the olfactory system, resonating with the Bruce effect in mice. In the Bruce effect, the particularities of male body-odor are also a factor in the effect. Study design, size, duration We set out to ask whether the body-odor (BO) of men in uRPL is different from the BO of control men. To test this, we used two main approaches: have women smell BOs from uRPL-men and control-men and rate the perceived odor; and sample the BOs using a machine (electronic nose) and test if the composition of the BOs is objectively different. Participants/materials, setting, methods We collected BOs from spouses of uRPL and control women. We recruited women with uRPL, control women (with no history of pregnancy losses) and nulliparous women to sniff the BOs and rate them for perceived intensity, pleasantness, sexual attraction, and fertility. We then used an electronic nose (eNose, Airsense) to sample the BOs and used a Linear SVM classifier on this data, to try and classify the BOs to the two groups. Main results and the role of chance Twenty-one women with uRPL and 24 control women sniffed and rated 34 BO jars (17 uRPL-men). We found that uRPL-men BO was rated as more pleasant, sexually attractive and fertile than control men (rmANOVAs for each parameter but intensity revealed a significant effect of male group (all F(1,43)&amp;gt;14.24, all p &amp;lt; 0.001), no women-group effect and no interactions). We then recruited 51 nulliparous women, not related to the original study, to do the same task, and the results replicated: nulliparous women rated uRPL-men’s BO significantly more pleasant, sexually attractive and fertile than control men’s BO (all t(50)&amp;gt;2.88, all p &amp;lt; =0.006), while the intensity was not different (t(50)=0.87, p = 0.38). We then used a PEN3 eNose to sample 37 male BOs (18 uRPL). The PEN3 eNose contains 10 different metal oxide sensors, and each sensor is coated in a unique material that makes it sensitive to different sets of chemical compounds. Based on the data from the eNose, a Linear SVM classifier successfully classified the odors to uRPL-men or control-men at 69.9% accuracy in a five-fold cross-validation test (p &amp;lt; 0.001 estimated by repeating the process 1000 times and shuffling the labels). Limitations, reasons for caution This study shows an association between the body-odor of men and uRPL, however it shows a correlative connection (not causative). Therefore, the interpretation for these current results are limited. Wider implications of the findings These initial results suggest that uRPL-men’s and control-men’s BO have different chemical composition. This implies a possible contribution of men to the effect we observed in our previously published study, and combined, further strengthens a link between uRPL and the olfactory system that we continue to investigate. Trial registration number not applicable

P-431 Perinatal outcomes after recurrent pregnancy loss: a systematic review and meta-analysis

Abstract Study question Are women with recurrent pregnancy loss (RPL) at higher risk of adverse perinatal outcomes in a subsequent pregnancy? Summary answer Women with a history of RPL have significant higher odds of adverse perinatal outcomes in a subsequent pregnancy. What is known already Studies have suggested that RPL women may have higher risks for obstetrical and perinatal complications such as hypertensive disorders, placental abruption, placenta accreta spectrum disorders, preterm delivery, and perinatal death in a subsequent pregnancy compared to those without an RPL history. However, the existing body of research presents a conflicting narrative, thus highlighting the need for a comprehensive understanding of the implications of RPL on pregnancy outcomes. Study design, size, duration A systematic review and meta-analysis was conducted. MEDLINE, EMBASE, Google Scholar and Cochrane databases were searched from inception until July 2023 for studies on RPL and adverse perinatal outcomes. Data was extracted by two independent reviewers. Participants/materials, setting, methods DerSimonian and Laird random effect meta-analyses were performed to pool effect estimates. Results were presented as odd ratios with their respective 95% confidence intervals. Subgroup analyses were conducted for those with unexplained RPL and by number of pregnancy losses. Sensitivity analysis using only high-quality studies and influence analysis were performed. The Newcastle-Ottawa Scale was used to assess for risk of bias. Main results and the role of chance The systematic search yielded 8,915 records, of which 42 studies (n = 5,619,124) were included in our meta-analysis. Women with RPL had higher odds of pre-eclampsia (OR 1.19; 95% CI, 1.03-1.37), pregnancy-induced hypertension (OR 1.24; 95% CI, 1.03-1.48), gestational diabetes (OR 1.76; 95% CI, 1.28-2.44), cesarean delivery (OR 1.65, 95% CI, 1.47-1.85), placental abruption (OR 1.57; 95% CI, 1.37-1.81), placenta previa (OR 1.93; 95% CI, 1.59-2.35; 7 studies), placenta accreta (OR 4.42; 95% CI, 3.09-6.33), preterm birth (OR 1.79; 95% CI, 1.65-1.93), very preterm birth (OR 2.58; 95% CI, 2.08-3.18), small for gestational age (OR 1.31; 95% CI, 1.15-1.78), congenital anomalies (OR 1.25; 95% CI, 1.02-1.53), stillbirth (OR 1.25; 95% CI, 1.04-1.51) and perinatal death (OR 2.04; 95% CI, 1.58-2.71) compared to women without a history of RPL. There was no association with aneuploidy. Limitations, reasons for caution Significant inter-study heterogeneity and inconsistent adjustment for confounders was noted across included studies. Wider implications of the findings RPL patients are at higher odds of adverse perinatal outcomes in a subsequent pregnancy, and therefore require additional counselling and monitoring in said pregnancy. There is an urgent need for further prospective research clarifying the relationship between RPL and perinatal outcomes. Trial registration number N/A

O-032 Intravenous immunoglobulin and prednisolone to women with unexplained recurrent pregnancy loss undergoing assisted reproductive technology treatment: a randomized, double-blinded, placebo-controlled trial

Abstract Study question Does intravenous immunoglobulin (IVIG) and prednisolone in combination affect ongoing pregnancy rate among patients with recurrent pregnancy loss (RPL) after assisted reproductive technology (ART) treatment? Summary answer The results of this trial will provide important information about whether immunomodulatory treatment to RPL patients undergoing ART treatment can increase clinical pregnancy rate. What is known already Two retrospective cohort studies suggest that IVIG and prednisolone in combination result in a 34-37% live birth rate in RPL patients undergoing ART which is higher than the expected 12% for patients with RPL after ART. A randomized controlled trial (RCT) testing IVIG in RPL patients conceiving naturally indicated that very early administration of IVIG caused more positive effects than late administration, and prospective cohort studies suggest that treatment efficacy depends on presence of immune disturbances. No RCT has tested the IVIG/prednisolone combination starting before implantation and continued in very early pregnancy for RPL patients undergoing ART. Study design, size, duration In a randomized, double-blinded, placebo-controlled trial, patients undergoing IVF/ICSI/FET were treated with 400mg/kg IVIG and 5-10mg/day oral prednisolone or IV human albumin and oral placebo between January 2021 and March 2024. Oral treatment was administered from day one of menstrual cycle to GW 8 + 4, while IV treatment was given once in a short time interval before or after embryo transfer and repeated three times before GW 8 + 0. Primary outcome was ongoing pregnancy in GW 12 Participants/materials, setting, methods Seventy-four women &amp;lt;41 years old with ≥2 consecutive biochemical or clinical early pregnancy losses after ART were randomized 1:1 and underwent trial treatment along with their next IVF/ICSI/FET treatment. Patients were followed with weekly ultrasound scans in first trimester, however, if no implantation occurred, trial participation ended, and no re-entry was allowed. Exclusion criteria included antiphospholipid syndrome, BMI &amp;gt;35, uterine malformations, parental chromosomal translocations, AMH &amp;lt;4 pmol/l, drug contraindications, thyroid disease, and prior IVIG treatment. Main results and the role of chance Seventy-four patients have been randomized, and currently we are awaiting the last two patients to complete the treatment protocol before the code can be disclosed. Blinded interim analysis after inclusion of 38 patients showed no serious adverse events and an ongoing pregnancy rate of 30.0% and 9.5% (RR 1.8, 95% CI 1.0-3.1, Fisher’s exact test: p = 0.13), in the two allocation groups, respectively. Final, unblinded data on ongoing pregnancy rate, miscarriage rate and adverse events will be presented at the Congress if selected for presentation. Limitations, reasons for caution No published study has tested the same treatments in comparable patient groups which could have been the basis for the sample-size calculation, and the study is therefore at risk for being underpowered to evaluate the treatment effect in patients suffering from a combination of infertility, recurrent implantation failure, and RPL. Wider implications of the findings Blood samples were collected before first IV treatment and approximately 4 weeks later, which allow analysis for immunological disturbances and searching for biomarkers identifying those who will benefit from the treatment. This treatment could potentially increase success rate in patients undergoing ART after multiple unsuccessful treatment attempts. Trial registration number NCT04701034

P-386 The effect of intravenous immunoglobulin versus placebo in patients with recurrent pregnancy loss: a systematic review and meta-analysis of randomized trials

Abstract Study question In women with recurrent pregnancy loss (RPL), how does intravenous immunoglobulin (IVIg) compared with placebo affect live birth rate (LBR) in the first subsequent pregnancy? Summary answer IVIg significantly improved LBR in the per protocol (PP), but not the intention to treat (ITT) analysis. LBR increased significantly with number of pregnancy losses. What is known already RPL is defined as two or more pregnancy losses before 24 weeks of gestation, impacting 1-2% of fertile couples. It results from diverse causes, and immunological factors are increasingly implicated in unexplained RPL cases. IVIg has been studied as a treatment with various proposed mechanisms. Existing research on IVIg in RPL has shown conflicting results, but a recent Japanese randomized controlled trial (RCT) reported a significantly increased LBR when IVIg was administered early and in high-dose. Study design, size, duration We conducted a systematic review and meta-analysis of relevant (RCTs, incorporating individual patient data (IPD) to evaluate IVIg’s impact on LBR in RPL patients. Participants/materials, setting, methods This study adhered to PRISMA guidelines and was registered in PROSPERO (ID CRD42023375788). We searched PubMed, Embase, and Cochrane libraries for relevant RCTs up to March 20, 2023. We conducted a meta-analysis with predefined primary (live birth and clinical pregnancy rates) and secondary outcomes. Risk ratios with 95% confidence intervals were calculated for dichotomous outcomes, and mean and standard deviation for continuous variables. We contacted the original authors to perform subgroup analyses based on IPD. Main results and the role of chance A total of 10 RCTs comprising 594 women were included in the meta-analysis, and IPD were retrieved from six RCTs including 354 women. No statistically significant results in LBR between IVIg and placebo treated women were found in the ITT analysis (RR: 1.02 [95% CI 0.86-1.22] p = 0.78). In the PP analysis, LBR was increased in the IVIg group compared with placebo (RR: 1.23 [1.00-1-50]). A statistically significant increase in clinical pregnancy rate was found in the IVIg group compared with placebo among women receiving high dose (median ³ 77.5 g) IVIg (RR: 1.79, [95% CI 1.21-2.65], p = 0.004). Furthermore, a statistically significant decrease in pregnancy loss rate was found in patients receiving high doses of IVIg (RR: 0.76 [95% CI 0.60-0.96], p = 0.02) compared to placebo. In the IPD analysis, RRs for live birth in the IVIg group compared with placebo increased steadily with the number of previous pregnancy losses. RRs for live birth in patients receiving IVIg compared with placebo were 5.26 (1.58-17.53) and 7.50 [1.20-47.05) in patients with ≥6 and ≥7 consecutive pregnancy losses, respectively. In analyses of IPD data adjusted for maternal age, the RRs for live birth were almost similar. Limitations, reasons for caution Limitations in the systematic review include potential bias due to financial support from pharmaceutical companies in half of the studies; potential confounding in subgroup analysis, missing individual patient data; and clinical and methodological heterogeneity among the included RCTs, which all may impact the overall reliability of results. Wider implications of the findings The findings highlight the importance of patient selection and personalized treatment. The PP analysis favored IVIg, emphasizing importance of protocol adherence. Secondly, the effectiveness of IVIg seems to increase with number of previous consecutive pregnancy losses. Thirdly, the dose of IVIg seem to impact its effectiveness. Trial registration number CRD42023375788

Hydroxychloroquine in recurrent pregnancy loss: data from a French prospective multicenter registry.

What are the outcomes of pregnancies exposed to hydroxychloroquine (HCQ) in women with a history of recurrent pregnancy loss (RPL), and what factors predict the course of these pregnancies beyond the first trimester? In our cohort of pregnancies in women with a history of RPL exposed to HCQ early in pregnancy, we found that the only factor determining the success of these pregnancies was the number of previous miscarriages. Dysregulation of the maternal immune system plays a role in RPL. HCQ, with its dual immunomodulating and vascular protective effects, is a potential treatment for unexplained RPL. The FALCO (Facteurs de récidive précoce des fausses couches) registry is an ongoing French multicenter infertility registry established in 2017 that includes women (aged from 18 to 49 years) with a history of spontaneous RPL (at least three early miscarriages (≤12 weeks of gestation (WG)) recruited from several university hospitals. Spontaneous pregnancies enrolled in the FALCO registry with an exposure to HCQ (before conception or at the start of pregnancy) were included. Pregnancies concomitantly exposed to tumor necrosis factor inhibitors, interleukin-1 and -2 inhibitors, intravenous immunoglobulin, and/or intravenous intralipid infusion, were excluded. Concomitant treatment with low-dose aspirin (LDA), low-molecular weight heparin (LMWH), progesterone, and/or prednisone was allowed. All patients underwent the recommended evaluations for investigating RPL. Those who became pregnant received obstetric care in accordance with French recommendations and were followed prospectively. The main endpoint was the occurrence of a pregnancy continuing beyond 12 WG, and the secondary endpoint was the occurrence of a live birth. One hundred pregnancies with HCQ exposure in 74 women were assessed. The mean age of the women was 34.2 years, and the median number of previous miscarriages was 5. Concomitant exposure was reported in 78 (78%) pregnancies for prednisone, 56 (56%) pregnancies for LDA, and 41 (41%) pregnancies for LMWH. Sixty-two (62%) pregnancies ended within 12 WG, the other 38 (38%) continuing beyond 12 WG. The risk of experiencing an additional early spontaneous miscarriage increased with the number of previous miscarriages, but not with age. The distributions of anomalies identified in RPL investigations and of exposure to other drugs were similar between pregnancies lasting ≤12 WG and those continuing beyond 12WG. The incidence of pregnancies progressing beyond 12 WG was not higher among pregnancies with at least one positive autoantibody (Ab) (i.e. antinuclear Ab titer ≥1:160, ≥1 positive conventional and/or non-conventional antiphospholipid Ab, and/or positive results for ≥1 antithyroid Ab) without diminished ovarian reserve (18/51, 35.3%) than among those without such autoantibody (18/45, 40.0%) (P = 0.63). Multivariate analysis showed that having ≤4 prior miscarriages was the only factor significantly predictive for achieving a pregnancy > 12 WG, after adjustment for age and duration of HCQ use prior to conception (adjusted odds ratio (OR) = 3.13 [1.31-7.83], P = 0.01). Our study has limitations, including the absence of a control group, incomplete data for the diagnostic procedure for RPL in some patients, and the unavailability of results from endometrial biopsies, as well as information about paternal age and behavioral factors. Consequently, not all potential confounding factors could be considered. Exposure to HCQ in early pregnancy for women with a history of RPL does not seem to prevent further miscarriages, suggesting limited impact on mechanisms related to the maternal immune system. The research received no specific funding, and the authors declare no competing interests. clinicaltrial.gov NCT05557201.