Recurrent Spontaneous Miscarriage: a Comparison of International Guidelines

The microbiome in recurrent pregnancy loss - A scoping review

Recurrent pregnancy loss (RPL) is a troubling condition that affects couples worldwide. Despite extensive research efforts, many RPL cases remain unexplained, highlighting the need for novel approaches to unravel its underlying mechanisms. Recent advances in microbiome research have shed light on the potential role of the microbiome in reproductive health and outcomes. Based on a systematic literature research, this review aims to comprehensively explore the current understanding of the microbiome's involvement in RPL, focusing on the vaginal, endometrial, and gut microbiomes. Evidence from the available studies is examined to explain the relationship between the microbiome and RPL. Furthermore, we discuss the diagnostic potential of the microbiome, therapeutic interventions, and future directions in microbiome research for RPL. Understanding the complex interactions between the microbiome and reproductive health holds promise for developing targeted interventions to help patients today diagnosed as unexplained.

The natural cycle protocol of endometrial preparation for frozen embryo transfer decreases the miscarriage rate in women with recurrent pregnancy loss

OBJECTIVE

To investigate whether different endometrial preparation methods lead to different results.

DESIGN

Retrospective cohort study.

PATIENTS

Women with recurrent pregnancy loss undergoing frozen embryo transfer (FET).

INTERVENTIONS

Natural cycle (NC) protocol (n = 111) with no drug or human chorionic gonadotropin (HCG) used for endometrial preparation, vs. the hormone replacement therapy (HRT) protocol (n = 797) with estrogen or gonadotropin releasing hormone agonist (GnRH-a) plus estrogen used for endometrial preparation.

MAIN OUTCOME MEASURES

Miscarriage rate and live birth rate (LBR).

RESULTS

Compared to women in the HRT protocol, women undergoing NCs had fewer previous FET cycles, lower antral follicle counts (AFCs), fewer oocytes retrieved and a thicker endometrium on the day of progesterone administration. Women in the HRT group had a higher miscarriage rate (29.4% vs. 17.2%) and a lower LBR (37% vs. 46.9%) than the rates of women in the NC group. Univariate analysis showed that female age also had a negative association with the miscarriage rate. Logistic regression indicated that endometrial preparation using the NC protocol was linked to a decreased likelihood of miscarriage.

CONCLUSIONS

The NC protocol decreased the miscarriage rate and increased the LBR for patients with recurrent pregnancy loss compared with the HRT protocol.

The Role of Acetylsalicylic Acid in the Prevention of Pre-Eclampsia, Fetal Growth Restriction, and Preterm Birth

BACKGROUND

Recent studies suggest that low-dose acetylsalicylic acid (ASA) can lower pregnancy-associated morbidity.

METHODS

This review is based on pertinent publications that were retrieved by a selective search in PubMed, with special attention to systematic reviews, metaanalyses, and randomized controlled trials.

RESULTS

Current meta-analyses document a reduction of the risk of the occurrence of pre-eclampsia (RR 0.85, NNT 50), as well as beneficial effects on the rates of preterm birth (RR 0.80, NNT 37), fetal growth restriction (RR 0.82, NNT 77), and perinatal death (RR 0.79, NNT 167). Moreover, there is evidence that ASA raises the rate of live births after a prior spontaneous abortion, while also lowering the rate of spontaneous preterm births (RR 0.89, NNT 67). The prerequisites for therapeutic success are an adequate ASA dose, early initiation of ASA, and the identification of women at risk of pregnancy-associated morbidity. Side effects of treatment with ASA in this patient group are rare and mainly involve bleeding in connection with the pregnancy (RR 0.87, NNH 200).

CONCLUSION

ASA use during pregnancy has benefits beyond reducing the risk of pre-eclampsia. The indications for taking ASA during pregnancy may be extended at some point in the future; at present, in view of the available evidence, it is still restricted to high-risk pregnancies.

Biopsy-free profiling of the uterine immune system in patients with recurrent pregnancy loss and unexplained infertility

RESEARCH QUESTION

What are the differences in menstrual blood lymphocytes between controls, patients with recurrent pregnancy loss (RPL) and patients with unexplained infertility (uINF)?

DESIGN

Prospective study including 46 healthy controls, 28 RPL and 11 uINF patients. A feasibility study compared lymphocyte compositions of endometrial biopsies and menstrual blood collected during the first 48 h of menstruation in seven controls. In all patients, peripheral and menstrual blood from the first and subsequent 24 h were analysed separately by flow cytometry, focusing on the main lymphocyte populations and natural killer (NK) cell subsets.

RESULTS

The first 24 h of menstrual blood resembles the uterine immune milieu as tested by endometrial biopsy. RPL patients showed significantly higher menstrual blood CD56+ NK cell numbers than controls (mean ± SD: 31.13 ± 7.52% versus 36.73 ± 5.4%, P = 0.002). Menstrual blood CD56dimCD16bright NK cells within the CD56+ NK cell population were decreased in RPL (16.34 ± 14.65%, P = 0.011) and uINF (15.7 ± 5.91%, P = 0.02) patients versus control (20.42 ± 11.53%). uINF patients had the lowest menstrual blood CD3+ T cell counts (38.81 ± 5.04%, control versus uINF: P = 0.01) and cytotoxicity receptors NKp46 and NKG2D on CD56brightCD16dim cells were higher in uINF (68.12 ± 11.84%, P = 0.006; 45.99 ± 13.83%, P = 0.01, respectively) and RPL (NKp46: 66.21 ± 15.36%, P = 0.009) patients versus controls. RPL and uINF patients had higher peripheral CD56+ NK cell counts versus controls (11.42 ± 4.05%, P = 0.021; 12.86 ± 4.29%, P = 0.009 versus 8.4 ± 3.5%).

CONCLUSIONS

Compared with controls, RPL and uINF patients had a different menstrual blood-NK-subtype profile, indicating an altered cytotoxicity. In future studies, this non-invasive analysis might enable identification and monitoring of patients receiving immunomodulatory medications.

Peripheral blood natural killer cell cytotoxicity in recurrent miscarriage: a systematic review and meta-analysis

Dysregulated natural killer (NK) cells have been associated with recurrent miscarriages (RM). Studies have suggested that high peripheral blood NK cell cytotoxicities (pNKCs) are associated with an increased risk of RM. The aim of this systematic review (SR) and meta-analysis (MAs) is to investigate the difference in pNKC between nonpregnant and pregnant women with RM and controls and determine whether pNKC is reduced by immunotherapy. We searched the PubMed/Medline, Embase, and Web of Science databases. The MAs were conducted to compare pNKCs between women with and without RM before and during pregnancy as well as pre- and post-immunotherapy. Risk of bias in nonrandomized studies was assessed by the Newcastle-Ottawa Scale. Statistical analysis was performed using the Review Manager software. A total of 19 studies were included in the SR and 14 studies in the MAs. The MAs revealed higher pNKCs among nonpregnant women with RM compared to controls (MD, 7.99 95 %CI 6.40-9.58; p < 0.00001). pNKCs were also higher in pregnant women with RM than in pregnant controls (MD, 8.21 95 %CI 6.08-10.34; p < 0.00001). Women with RM showed significantly decreased pNKCs after the immunotherapy compared to before (MD, -8.20 95 %CI -10.20 - -6.19; p < 0, 00001). Additionally, there is an association between high pNKCs and the risk of pregnancy loss in women with RM. However, included studies showed substantial heterogeneities regarding the inclusion criteria of patients, techniques measuring pNKC, and types of immunotherapies. More studies are needed to evaluate the clinical efficiency of pNKCs in managing RM.

The use of immunotherapies for recurrent miscarriage: An overview of systematic reviews and meta-analysis

Immunotherapies have been a treatment proposed for recurrent miscarriages (RMs). The use of immunotherapies remains not recommended in the management of couples with RM. This overview of systematic reviews and meta-analysis (SRs-MAs) aims to identify and evaluate the quality of SRs-MAs that studied the effectiveness of immunotherapies in the treatment of RM patients. SRs-MAs were searched in PubMed/Medline, Embase, and Web of Science. SRs-MAs were analyzed using AMSTAR-2, PRISMA 2020, Risk of Bias in Systematic (ROBIS), and Grading of Recommendations Assessment, Development, and Evaluation (GRADE) tools to evaluate the methodological quality, reporting quality, risk of bias, and evidence quality of included SRs-MAs, respectively. This review included 20 SRs-MAs that evaluated the following immunotherapies: intravenous immunoglobulin (13 publications), lymphocyte immunotherapy (6 publications), corticosteroids (3 publications), and lipid emulsion (1 publication). SRs-MAs were rated as high methodological, moderate, and critically low quality in 14 (70 %), 1 (5 %), and 5 (25 %) SRs-MAs and high reporting, moderate, and low quality in 13 (65 %), 4 (20 %), and 3 (5 %) SRs-MAs, respectively. The overall risk of bias revealed a low risk of bias for three-quarters of the SRs-MAs. Grading of Recommendations Assessment, Development, and Evaluation (GRADE) analysis resulted in 23 outcomes, of which 4, 3, 5, and 11 results were of high, moderate, low, and very low quality, respectively. An improvement has been observed over the past few years in the quality of systematic reviews (SR)-MAs that have investigated the efficacy of intravenous immunoglobulin, lymphocyte immunotherapy, lipid emulsion therapy, and corticosteroids as a therapy for RM.

Age-related changes in CD4+ T and NK cell compartments may contribute to the occurrence of pregnancy loss in advanced maternal age

A recent study characterized novel immune cell subsets (T, NK, and γδ T cell subsets) related to recurrent pregnancy loss (RPL). This study aims to assess whether these RPL-related immune cell subsets are affected by aging. The percentages of peripheral blood immunes cells from nulligravida women (NGW), women with a history of normal pregnancy (NP), and women with a history of pregnancy loss (PL) were detected by flow cytometry. The correlations between maternal age and cell percentages were assessed. We found a significant positive correlation between PL and maternal age. The percentages of effector memory CD4⁺ T (CD3⁺ CD4⁺ CD45RA¯ CCR7¯), terminally differentiated CD4⁺ T (CD3⁺ CD4⁺ CD45RA⁺ CCR7¯), and mature NK cells (CD3¯ CD56^+lo) significantly increased with maternal age. A significant decrease in the percentage of Naïve CD4⁺ T cells (CD3⁺ CD4⁺ CD45RA⁺ CCR7⁺) with age was observed in women from the NP group. Women aged 35 or older had significantly higher percentages of effector memory CD4⁺ T cells, terminally differentiated CD4⁺ T cells, and mature NK cells than younger women. Maternal age positively correlates with terminally differentiated CD4⁺ T, effector memory CD4⁺ T, and mature NK cell percentages. In contrast, an inverse correlation was observed between Naïve CD4⁺ T cell and age among women from the NP group. Our findings indicate that age-related CD4⁺ T and NK cell dysregulation might be involved in the pathogenesis of PL in women with advanced maternal age. The underlying mechanism needs further investigation.

Prevalence and associated factors of recurrent pregnancy loss in Nigeria according to different national and international criteria (ASRM/ESHRE vs. WHO/RCOG)

Background

In low-and middle-income countries, no conclusive research explains the prevalence and associated factors of women with a history of recurrent pregnancy loss (RPL). Some authorities have recommended further scientific research on the effect of various definitions of RPL.

Objective

To assess prevalence and associated factors of RPL among pregnant women in Nigeria according to different national and international criteria: the American Society for Reproductive Medicine/ European Society for Human Reproduction and Embryology (ASRM/ESHRE; two losses) and the World Health Organization/ Royal College of Obstetricians and Gynecologists (WHO/RCOG; three consecutive losses) criteria.

Methods

This is a cross-sectional analytical study wherein, pregnant women with prior RPL were investigated. The outcome measures were prevalence and risk factors. The associations between independent variables and outcome variable were explored using bivariate and multivariable logistic regression models. The results of these analyses were reported as adjusted odds ratios (AORs) with 95% confidence intervals (95%CI). Factors associated with RPL were identified using multivariate regression models.

Result

Of the 378 pregnant women interviewed, the overall prevalence of RPL in this study was found to be 15.34% (95% confidence interval = 11.65%-19.84%). The prevalence of RPL was 15.34% (58/378; 95%CI = 11.65%-19.84%) and 5.29% (20/378; 95%CI = 3.23%-8.17) according to the ASRM and the WHO criterion respectively. Regardless of diagnostic criteria, unexplained (AOR = 23.04; 95%CI: 11.46-36.32), endocrine disturbances (AOR = 9.76; 95%CI: 1.61-63.19), uterine abnormalities (AOR = 13.57; 95%CI: 3.54-50.60), and antiphospholipid syndrome (AOR = 24.59; 95%CI: 8.45-71.04) were positively and independently associated with RPL. No significant risk factors were seen when the ASRM/ ESHRE criterion vs. WHO/RCOG criterion were compared. Advanced maternal age was significantly higher in secondary than in primary type of RPL.

Conclusion

The prevalence of RPL was 15.34% and 5.29% according to ASRM/ESHRE and WHO/RCOG criterion respectively, with secondary type predominating. No significant differences with regard to risk factors were seen according to diagnostic criteria studied, though advanced maternal age was significantly higher in secondary RPL. Further research is needed to confirm our findings and to better characterize the magnitude of differences.

Basic biochemical and hematological parameters of structural hemoglobin variants in the postpartum women and their respective newborn from Manaus, Amazonas, Brazil

The present study aimed at estimating the prevalence of structural hemoglobinopathies in newborn and describing the hematological and biochemical characteristics between postpartum women (PW) and their respective newborns (NB) at a public maternity hospital in Manaus, Amazonas state, Brazil. In total, 825 NB and 820 PW were included in the study. Hematological and biochemical analysis and screening of structural hemoglobinopathies were performed and compared in groups of individuals (NICU or not; hemoglobin genotypes; gestational age and prenatal). The age of PW ranged from 13 to 44 years old (mean of 23.7 ± 6.6 years), with 45.9% pregnant for the first time and 54.1% multiparous. Reported receiving prenatal care 88% and regarding the type of delivery, 47.7% had delivered by cesarean section. Among the births, 19.4% were born premature and 8.3% were admission to the neonatal intensive care unit (NICU). The male NB represented 53.4% of the total. Sickle cell trait (FAS) was found in 16 (1.94%) and heterozygous for D hemoglobin (FAD) in 6 (0.73%) newborns. A statistically significant values was found between the previous history of miscarriage and increase of Mean corpuscular volume (MCV) (p < .001), Red blood cell distribution width (RDW) (p = .003), total and indirect bilirubin concentration (p < .001) and LDL cholesterol (p = .004). Hemoglobin levels below 13.5 g/dL was found in 66% black newborns, compared with 15% of Afro-Brazilian and 5% of whites. The frequency of structural hemoglobinopathies was higher in African-Brazilian newborn babies (78%) and those who with low birth weight had a higher frequency of NICU (35.7%). Interestingly, underage mothers had a higher frequency of NB with low birth weight and premature birth. Postpartum women who had children carriers of FAS and FAD had a higher frequency of urinary tract infection (65.2%) and moderate anemia (23.8%). This study estimated for the first time the prevalence of structural hemoglobinopathies in NB in Manaus, Amazonas, Brazil. Despite the small prevalence of, we highlight the importance of early diagnosis of hemoglobin variants, contributing to the improvement of the quality of life of PW and your NB, reinforce the need to implement educational and prevention programs to raise awareness among the population and in order to counsel parents regarding the probability of having a child with abnormal hemoglobins homozygous as HbSS or HbCC.

The psychological status mediates the effect of indoor air pollution on recurrent spontaneous abortion

BACKGROUND

Indoor air pollution (IAP) exposure and psychological status have been recognized as important risk factors for adverse pregnancy outcomes, but their mediating effects on recurrent spontaneous abortion (RSA) have not been analyzed. Therefore, the purpose of this study is to explore the association between IAP and RSA and to examine the mediating effect of psychological status on their association.

METHODS

This study included 830 RSA cases and 2156 controls in Gansu province, China. The Self-Rating Anxiety Scale (SAS) and Self-Rating Depression Scale (SDS) questionnaires were used to collect information on participants' psychological status. The IAP exposure was collected by the survey on cooking fuel use, kitchen ventilation characteristics, cooking styles, and indoor smoking, etc. Multivariable logistic regression was used to examine the associations between IAP exposure and RSA. The mediation analysis was used to evaluate the mediation effects of IAP and psychological status on RSA while controlling for confounding.

RESULTS

Among these cases, 16.87% cooked with unclean cooking fuel (UCF) and 37.00% lacked cooking ventilation, which was much higher than the controls. Active smoking and the use of UCF were associated with RSA, with an odds ratio (OR) of 3.374 [95% confidence interval (CI): 1.510-7.541] and 1.822 (95% CI: 1.328-2.500), respectively. We found that the use of a range hood was a protective factor for RSA, with an OR of 0.590 (95% CI: 0.463-0.752). There was a significant mediation effect of depression on the association between IAP and RSA, which accounted for 5.61%-9.22% of the total effect of IAP on RSA.

CONCLUSION

The IAP may be an important risk factor for RSA, which may be intensified by the poor psychological status, and the use of ventilation equipment when cooking is a protective factor for RSA.

Treatment of septate uterus

Although there is insufficient evidence supporting the link between septate uterus and infertility, there are many studies demonstrated the effect of spetal incision on pregnancy in women diagnosed with septate uterus associated with infertility. Hysteroscopic metroplasty can significantly improve the reproductive performance of those with septate uterus. Some Müllerian malformations can be healed by surgery. The accurate diagnosis and appropriate therapeutic approch are fundamental for successful treatment. Any attempt at surgical correction of uterine abnormalities must be aimed at preserving or improving reproductive function. Among congenital uterine anomalies, septate uterus is the most amenable to simple hysteroscopic treatment. The resection of the septum is performed as standard treatment worldwide.

Effect of thyroid function on assisted reproduction outcomes in euthyroid infertile women: A single center retrospective data analysis and a systematic review and meta-analysis

BACKGROUND

The influence of thyroid-stimulating hormone (TSH) on gestational outcomes have been studied and checked whether differing TSH levels are relevant on human reproduction outcomes. International guidelines recommend TSH values <2.5 mIU/L in women trying to conceive, since values above this level are related to a higher frequency of adverse reproductive outcomes. This study aimed to evaluate whether TSH values correlate with different gestational outcomes in euthyroid infertile women without autoimmune thyroid disease.

METHODS

A retrospective cohort study was conducted involving 256 women who underwent in vitro fertilization (IVF) treatment. The participants were divided into two groups: TSH 0.5-2.49 mIU/L (n=211) and TSH 2.5-4.5 mIU/L (n=45). The clinical data, hormonal profiles and reproductive outcomes were compared between groups. Additionally, a systematic review with meta-analysis following the PRISMA protocol was carried out in PubMed/MEDLINE, EMBASE, and SciELO, with no time or language restrictions, for articles comparing TSH groups named "low TSH" (<2,5 mIU/L) and "high TSH" (≥2.5 mIU/L). A meta-analysis of proportions was performed with pooled estimates expressed as relative risk (RR) of events and a random effects model.

RESULTS

Age, BMI, free thyroxine levels (FT4) hormonal profile and IVF outcomes were not different between groups, neither gestational outcomes (p=0.982). Also, no difference was observed when the TSH and FT4 levels were compared between patients with positive or negative gestational outcomes (p=0.27 and p=0.376). Regarding the systematic review with meta-analysis, 17 studies from 2006 to 2022 were included, and added by this original retrospective research comprising 13.247 women undergoing IVF. When comparing the proportions of clinical pregnancy between the TSH groups, no significant difference was found (RR 0.93, 95% CI 0.80-1.08), with high between studies heterogeneity (I²: 87%; τ²: 0.0544; p<0.01). The number of deliveries was not significantly different between groups, despite a trend towards higher frequency in the high-TSH group (RR 0.96, 95% CI 0.90-1.02).

CONCLUSION

Variation in TSH levels within the normal range was not associated with pregnancy and delivery rates in women, without autoimmune thyroid disease, who underwent IVF treatment.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/, identifier CRD 42022306967.