MMP2 and MMP9 are associated with the pathogenesis of recurrent pregnancy loss through protein expression rather than genetic polymorphism.

Matrix metalloproteinases (MMPs) degrade extracellular matrix proteins and are important for placenta formation during early pregnancy. Recurrent pregnancy loss (RPL) is associated with abnormalities in endometrial extracellular matrix remodeling. This study aimed to elucidate the roles of MMP2 and MMP9 in RPL pathogenesis. In total, 295 women with a history of RPL and 101 controls were included in this genetic study. Genotype analysis was performed using polymerase chain reaction (PCR) restriction fragment length polymorphisms. For proteolytic analysis, decidua and villi were collected from 10 RPL-miscarried women with normal fetal chromosomes (NC) and 19 women with fetal chromosome aberrations (AC). The expression of MMP2 and MMP9 in the decidua and villi was measured by IHC and ELISA. All samples were collected after obtaining informed consent. There were no statistically significant differences in MMP2-735 C/T and MMP9-1562 C/T frequencies between women with RPL and the controls. There was no significant difference in MMP2 expression levels in the villi; however, MMP9 expression was significantly higher in normal fetal chromosomes. In the decidua, the expression of MMP2 in the NC group was significantly lower, and MMP9 in the NC group was significantly higher than in the AC group. Although no differences in MMP2-735 C/T and MMP9-1562 C/T gene polymorphisms were observed in the present study, it is suggested that differences at the protein level are involved in the pathogenesis of RPL since MMP expression is not only regulated by genes but also by local inflammation and various inductive signals.

Impaired decidualization and relative increase of PROK1 expression in the decidua of patients with unexplained recurrent pregnancy loss showing insulin resistance.

A recent meta-analysis revealed that patients with unexplained recurrent pregnancy loss (RPL) show higher insulin resistance compared to healthy controls. However, the etiology of RPL remains unknown. Prokineticin (PROK1), a pleiotropic uterine endometrial protein, is important for implantation and decidualization and is regulated by hypoxia and insulin. In this study, we investigated the decidualization status and the role of PROK1 in the decidua of patients with unexplained RPL showing insulin resistance. Thirty-two patients with unexplained RPL were included in this study. Following the diagnosis of a miscarriage, the decidua and villi of the patient were surgically collected. Fasting blood glucose and insulin levels were measured, and HOMA-ß was calculated. Using IHC and ELISA, the expression of IGFBP-1, PRL and PROK1 in the decidua and IGF-2 in the villi were analyzed in patients with euploid miscarriage with a high HOMA-ß index (n = 8) and compared to controls (euploid miscarriage with normal HOMA-ß: n = 12, aneuploid miscarriage with normal HOMA-ß: n = 12). The co-localization of PROK1 and IGFBP-1 was observed in the decidua by IHC. In the decidua of RPL patients with high HOMA-ß, the expression levels of IGFBP-1 and PRL were significantly lower, whereas the PROK1/IGFBP-1 ratio was significantly higher compared to that of the controls. IGF-2 expression in villi was significantly lower in RPL patients with high HOMA-ß. Impaired decidualization and excessive PROK1 production may have pathological implications in patients with unexplained RPL with insulin resistance, especially under the state of hyper insulin production.

Cervicovaginal microbiome in patients with recurrent pregnancy loss.

There have been few studies concerning an association between unexplained recurrent pregnancy loss (RPL) and the microbiome. A recent study including 67 patients demonstrated that an increase in Ureaplasma species in the endometrium raised the risk of miscarriage with an euploid karyotype. While endometrial sampling is invasive, cervicovaginal sampling is not. We compared vaginal and cervical microbiomes with a 16 S ribosomal RNA sequence between 88 patients with unexplained RPL and 17 healthy women with no history of miscarriage. We prospectively assessed risk factors for maternal colonization at a subsequent miscarriage without an aneuploid karyotype in patients. Cervicovaginal bacteria were dominated by Lactobacillus iners, Gardnerella vaginalis, Atopobium vaginae and Bifidobacterium breve in Japanese population. The proportions of Delftia and unknown bacteria in the cervix were significantly higher in patients with RPL than in controls. Streptococcus, Microbacterium, Delftia, Anaerobacillus and Chloroplast in the cervix were significantly higher in patients with a history of chorioamnionitis compared to the controls. The abundance of Cutibacterium and Anaerobacillus in the cervix was significantly higher in patients who had subsequently miscarried compared to those who gave birth. The miscarriage rate in patients with higher proportions of both Cutibacterium and Anaerobacillus (66.7%, 2/3) was significantly greater than that of patients who lacked these bacteria (9.2%, 6/65, adjusted odds ratio 16.90, 95% confidence interval 1.27-225.47, p = 0.032). The presence of certain bacteria could be a predictor of subsequent miscarriage without an aneuploid karyotype. The cervicovaginal microbiome might be useful for investigating a possible cause of RPL.

Hematocolpos due to lower vaginal agenesis in an adolescent girl.

Background: Hematocolpos due to imperforate hymen is an important differential diagnosis of abdominal pain in early adolescent stage. However, hematocolpos due to lower vaginal agenesis must be considered because the management differs. Case Presentation: A healthy 11-year-old girl presented with a 2-day left lower abdominal pain history. Her breast development had begun, but she had not reached menarche. Computed tomography showed high absorptive value liquid filling the upper vaginal to uterine cavity, a pale highly absorptive fluid component suggestive of hemorrhagic ascites in the abdominal cavity on both sides of the uterus, and normal bilateral ovaries. Magnetic resonance imaging diagnosed hematocolpos due to lower vaginal agenesis. The blood clot was aspirated with a transabdominal ultrasound-guided transvaginal puncture. Conclusion: History-taking, imaging tests, and appropriate collaboration with obstetrician/gynecologist with awareness of secondary sexual characteristics were crucial in this case.

The association between chronic deciduitis and recurrent pregnancy loss.

Chronic deciduitis (CD) is defined as the presence of lymphocytes or plasma cells in decidual tissue. CD suggests the presence of chronic endometritis (CE) which is associated with recurrent pregnancy loss (RPL). In this study, we examined the role CD plays in RPL patients with aneuploid and euploid miscarriage. The frequency of CD in 49 RPL patients (22 euploid and 27 aneuploid miscarriages) and 17 control women was assessed and the subsequent live birth rate (LBR) in the presence and absence of CD were compared. When only one CD138-positive endometrial stromal plasma cell (ESPC) was found per high-power field (HPF), we diagnosed small-positive CD (Grade 1). When a cluster of two or more CD138-positive ESPCs was found per HPF, we diagnosed it as CD Grade 2. The prevalence of Grade 1 was 18.2% (4/22) in patients with euploid miscarriage, 37.0% (10/27) in patients with aneuploid miscarriage and 23.5% (4/17) in control women. The prevalence of Grade 2 was 45.5% (10/22) in patients with euploid miscarriage, 55.6% (15/27) in patients with aneuploid miscarriage and 23.5% (4/17) in control women. There was a significant difference in the prevalence of CD (p = 0.015). The LBR of patients with CD was similar to that of patients without CD. CD was associated with RPL, especially in patients with aneuploid miscarriage. However, since there was no difference in the LBR of patients with or without CD in the next pregnancy, it was unclear whether CD was a contributing cause of RPL.

Characteristic DNA methylation profiles of chorionic villi in recurrent miscarriage.

Dysregulation of transcriptional programs that are tightly regulated by DNA methylation during placental and fetal development at different gestational stages, may cause recurrent miscarriage. Here, we examined genome-wide DNA methylation in chorionic villi and decidual tissues from patients suffering RM and from healthy women who had undergone artificial abortion (n = 5 each). We found that 13,426 and 5816 CpG sites were differentially methylated in chorionic villi and decidua, respectively. DNA methylation profiles of chorionic villi, but not decidua, in RM patients was clearly distinct from AA controls. Among the differentially methylated genes, the enhancer region of SPATS2L was significantly more highly methylated in RM patients (n = 19) than AA controls (n = 19; mean methylation level, 52.0%-vs.-28.9%, P < 0.001), resulting in reduced expression of SPATS2L protein in the former. Functionally, depletion of SPATS2L in extravillous trophoblast cells decreased their invasion and migration abilities. Our data indicate that particularly the chorionic villi in RM patients exhibit distinct DNA methylation profiles compared with normal pregnancies and that this changed DNA methylation status may impede the progression of embryo development via the altered expression of genes such as SPATS2L in the villi.

Abnormal ciliogenesis in decidual stromal cells in recurrent miscarriage.

Primary cilia regulate cellular signaling and are involved in both sensing and transducing extracellular stimuli. A recent study of patients with recurrent miscarriage (RM) identified mutations affecting DYNC2H1, which were involved in ciliary biogenesis. However, there has been no study concerning primary cilia in the decidua. We compared the number and the length of primary cilia in the decidua of 15 patients with unexplained RM with those of 7 pregnant controls who underwent an artificial termination of pregnancy. Immunohistochemistry was performed using antibodies against primary cilia, extravillous trophoblasts (EVTs), macrophages, uterine Natural Killer (uNK) cells, decidual stromal cells, and the activation of TGF-ß and CREB signaling in the decidua of early pregnancy was studied. The density of decidual stromal cells, but not EVTs, macrophages or uNK cells, was found to be significantly higher in the decidua of patients compared to controls. The percentage of ciliated decidual stromal cells was significantly decreased in patients. There was no difference in the primary ciliary length. Regarding TGF-ß signaling, p-Smad2 in these cells was diminished significantly in patients, and most of the TGF-ß-activated decidual stromal cells of both patients and controls had primary cilia. No difference in the activation of CREB was found. Abnormal primary cilia on decidual stromal cells may be one of the explanatory factors for unknown RM. The inactivation of TGF-ß signaling may lead to abnormal ciliogenesis in the decidua.

The investigation of calpain in human placenta with fetal growth restriction.

PROBLEM: The mechanism of fetal growth restriction (FGR) is not fully understood. In this study, we explored the contribution of the calpain-calpastatin system and the activated states of calpains in human FGR placenta. METHOD OF STUDY: The placentas were collected from patients of FGR (n = 17) and controls (n = 23) at elective cesarean sections in Nagoya City University Hospital and used for experiments upon informed consent. The existence and the expression of calpains and calpastatin in human placenta were compared between FGR and controls using immunohistochemistry, SDS-PAGE, and Western blotting. RESULTS: Staining of calpains (pre-, post-µ-calpain, pre-, post-m-calpain, and calpain-6) and calpastatin was observed in cytoplasm of trophoblast cells, both in FGR and control placenta. Pre-µ-calpain was located in the cytoplasm, and post-µ-calpain was located mainly in proximity to the cytoplasmic membrane. The expression of pre-µ-calpain was significantly higher (P < .001) and calpain-6 was significantly lower (P = .01) in FGR placentas. The inactive µ-calpain (80 kDa) was significantly elevated (P < .01), and active µ-calpain (76 kDa) was significantly decreased (P = .01) in FGR placentas. CONCLUSION: The results demonstrate that activation of µ-calpain is suppressed in FGR placentas and that calpain-6 in human placenta is involved in the pathology of FGR.

Levothyroxine and subclinical hypothyroidism in patients with recurrent pregnancy loss.

PROBLEM: The association between subclinical hypothyroidism (SCH) and recurrent pregnancy loss (RPL) remains unclear. We evaluated whether SCH affects subsequent live births and whether levothyroxine is effective in improving the live birth rate in patients with RPL. METHOD OF STUDY: This observational cohort study included 1418 pregnancies of 1014 patients with a history of 2 or more pregnancy losses, who were euthyroid or had hypothyroidism, and had at least one subsequent pregnancy outcome. Some patients with SCH, as defined as a TSH >2.5 mIU/L, were treated with levothyroxine, and these comprised the levothyroxine group. The prevalence of SCH, subsequent live birth rates per patient and per pregnancy were compared among patients with SCH treated with and without levothyroxine and patients with euthyroid. RESULTS: The prevalence of SCH was 14.4%. Subsequent live birth rates were 75.0% for the levothyroxine group, 68.6% for the untreated SCH group, and 70.1% for the euthyroid group. After excluding miscarriages with abnormal karyotypes, live birth rates were 89.2%, 90.0%, and 91.1%. The adjusted odds ratio (95%CI) was 0.95 (0.23-3.83) after controlling covariables when comparing SCH patients with and without treatment. The live birth rates per pregnancy were 93.1%, 85.7%, and 90.9%, respectively. The adjusted OR was 0.95 (0.23-3.83). CONCLUSION: Levothyroxine has no effect on improving the live birth rate in patients with RPL associated with SCH. Treatment in patients with RPL and SCH raised TSH levels (2.5-10mIU/L) might not be beneficial in improving the live birth rate.

Polo-like kinase 4 and Stromal antigen 3 are not associated with recurrent pregnancy loss caused by embryonic aneuploidy.

No genetic association with recurrent pregnancy loss (RPL) caused by embryonic aneuploidy has been found. Recent studies have indicated that the common genetic variant rs2305957, surrounding the PLK4 gene, contributes to mitotic-origin aneuploidy risk during human early embryo development. The decrease in meiosis-specific cohesin causes predivision of sister chromatids in the centromere and chromosome segregation errors. STAG3 is a component of cohesin and is a meiosis-specific gene. Our case-control study included 184 patients with RPL whose previous products of conception (POC) exhibited aneuploidy and 190 fertile control women without a history of miscarriage. We performed a genetic association study to examine the genotype distribution at PLK4 (rs2305957) and STAG3 in patients with RPL caused by aneuploidy compared with controls. Regarding STAG3, SNPs with a minor allele frequency (MAF) threshold > 0.05 that were predicted to be binding sites of transcription factors and that showed significant associations in expression quantitative trait locus (e-QTL) analysis were selected. No significant differences in the MAF or distribution in any model of PLK4 (rs2305957) and 5 selected tag SNPs in STAG3 were found between the patients and controls. A further genome-wide association study is needed since a combination of genetic risk alleles might be useful in predicting future age-dependent RPL caused by aneuploidy.

Attitudes toward preimplantation genetic testing for aneuploidy among patients with recurrent pregnancy loss in Japan.

AIM: To examine attitudes toward preimplantation genetic testing for aneuploidy (PGT-A) in patients with recurrent pregnancy loss (RPL) because it has been performed worldwide in spite of little evidence regarding whether it can improve the live birth rate and prevent miscarriage. There has been no study to examine attitudes toward PGT-A in patients with RPL. METHODS: We conducted a cross-sectional study that used a questionnaire to examine attitudes toward PGT-A, the desire for PGT-A and the factors associated with this desire in 386 patients with RPL between November 2014 and January 2019. RESULTS: Overall, 25.1% of patients desired PGT-A and 35.2% answered that they knew about it. Regarding the reasons for wanting PGT-A, 42.3% thought that it would insure a live birth and with complete case analysis, showed that the patients' wish for PGT-A as a means of giving live birth was affected by their IVF-ET history (adjusted odds ratio 2.7, 95% CI 1.2-7.2) and whether they had any knowledge of PGT-A (2.4, 1.1-5.3). Those with a higher total family income (3.5, 1.2-10.1) and a previous IVF-ET (4.6, 2.0-10.3) tended to want PGT-A as a means of avoiding miscarriage. CONCLUSION: The majority had no opinion or a poor knowledge of PGT-A. More patients who self-assessed as knowing about PGT-A or who had undergone IVF-ET had the above type of misunderstanding. Accurate and up-to-date information from facilities different from those in which PGT-A is performed is necessary before reaching a decision on PGT-A.

Danaparoid is effective and safe for patients with obstetric antiphospholipid syndrome.

Objectives: The objective is to evaluate whether danaparoid is effective in improving the live birth rate in patients with obstetric antiphospholipid syndrome (oAPS).Methods: This prospective study included 91 pregnancies of 60 patients with oAPS diagnosed according to criteria of the International Congress on APS. Live birth rates, adverse pregnancies and perinatal outcomes were compared among patients treated with danaparoid and low dose aspirin (danaparoid group, LDA), unfractionated heparin (UFH) and LDA (UFH group) and LDA and/or prednisolone (LDA group).Results: After excluding 11 miscarriages with abnormal embryonic chromosomes, one chemical pregnancy and one ectopic pregnancy, live birth rates were 87.5% (14/16) for the danaparoid group, 90.0% (36/40) for the UFH group and 63.6% (14/22) for the LDA group, respectively. The live birth rates of patients treated with danaparoid and UFH were similar and tended to be higher than that of patients treated with LDA, respectively (OR 4.0, 95% confidence interval 0.72-22.22 and 5.15, 1.33-20.00). No patient given danaparoid and one patient with UFH developed heparin-induced thrombocytopenia which resulted in a stillbirth. Another patient with UFH suffered a lumbar compression fracture.Conclusion: Danaparoid is effective for improving the live birth rate and is safe for patients with oAPS.

Attitude and perceptions toward miscarriage: a survey of a general population in Japan.

Miscarriage is the greatest complication of pregnancy, and 70-80% of early miscarriages are mostly due to chromosomal abnormalities in the embryo. There is no evidence that stress is a direct cause of miscarriage. Despite these findings, in a national US survey on the causes of miscarriage, many Americans mistakenly attributed miscarriage to the mental state or behavior of the women. We conducted a survey to assess public attitudes and perceptions regarding the cause and prevalence of miscarriage in Japan. We sent out a questionnaire consisting of 17 questions. The 5000 recipients consisted of men and women (1:1 ratio) aged 18-69 who resided in Aichi Prefecture. A total of 1257 recipients (25%) responded to the questionnaire and 1219 valid respondents (24%) were included in the analyses. Of these, 62% considered a genetic abnormality of the fetus as the cause of miscarriage. Participants who were female, highly educated, married and healthy gave significantly more correct responses. On the other hand, the majority wrongly assumed that a stressful event (65%) and long-standing stress (75%) to be causes of miscarriage. Participants who had no history of miscarriage as well as males answered significantly more incorrectly. Sixty-five percent of respondents thought that miscarriage occurred less than 15% of all pregnancies. Among respondents who had experienced miscarriage personally, 53 and 36% felt guilty and lonely, respectively. Many respondents blamed the woman for the miscarriage either in terms of her behavior or mental stress and considered the frequency of miscarriage to be lower than it actually is.

Pathogenic roles of anti-C1q antibodies in recurrent pregnancy loss.

Recurrent pregnancy loss (RPL) is often considered idiopathic, however excessive complement activation has been observed in pregnancy related manifestations. Anti-C1q antibodies (anti-C1q) are associated with the activation of complement pathway in lupus patients, while it remains unclear in RPL. Firstly, we showed that both the prevalence and titre of anti-C1q were significantly higher in unexplained RPL than in healthy parous individuals. Secondly, we established the murine model of anti-C1q induced pregnancy loss using a monoclonal anti-mouse C1q antibody, JL-1. In mice treated with JL-1, high ratio of pregnancy loss and fetal growth restriction were frequently observed and complement activation occurred. C5a receptor (C5aR) blockade cancelled these pathogenic changes in mice treated with JL-1. In conclusion, our study reveals an association between the prevalence of anti-C1q and RPL. Additionally, our murine model has indicated that anti-C1q can induce reproductive failure, which might be ameliorated by therapy targeting the C5-C5aR axis.

The first genome-wide association study identifying new susceptibility loci for obstetric antiphospholipid syndrome.

Antiphospholipid syndrome (APS) is the most important treatable cause of recurrent pregnancy loss. The live birth rate is limited to only 70-80% in patients with APS undergoing established anticoagulant therapy. Lupus anticoagulant (LA), but not anticardiolipin antibody (aCL), was found to predict adverse pregnancy outcome. Recent genome-wide association studies (GWAS) of APS focusing on aCL have shown that several molecules may be involved. This is the first GWAS for obstetric APS focusing on LA. A GWAS was performed to compare 115 Japanese patients with obstetric APS, diagnosed according to criteria of the International Congress on APS, and 419 healthy individuals. Allele or genotype frequencies were compared in a total of 426 344 single-nucleotide polymorphisms (SNPs). Imputation analyses were also performed for the candidate regions detected by the GWAS. One SNP (rs2288493) located on the 3'-UTR of TSHR showed an experiment-wide significant APS association (P=7.85E-08, OR=6.18) under a recessive model after Bonferroni correction considering the number of analyzed SNPs. Another SNP (rs79154414) located around the C1D showed a genome-wide significant APS association (P=4.84E-08, OR=6.20) under an allelic model after applying the SNP imputation. Our findings demonstrate that a specific genotype of TSHR and C1D genes can be a risk factor for obstetric APS.

Genotyping analysis of protein S-Tokushima (K196E) and the involvement of protein S antigen and activity in patients with recurrent pregnancy loss.

OBJECTIVE: Preston et al. indicated that Protein S (PS) deficiency was associated with stillbirths but not miscarriages. The PS-Tokushima missense variant was reported to serve as a genetic risk factor for deep vein thrombosis in the Japanese population. A previous cross-sectional study showed no increase in the prevalence of PS-Tokushima in patients with recurrent early pregnancy loss or in patients with intra uterine fetal death and/or fetal growth restriction. There has been limited number of prospective studies examining the pregnancy outcome in patients with both a PS deficiency and recurrent pregnancy loss (RPL). We examined the association between PS deficiency, PS-Tokushima and RPL. STUDY DESIGN: The study group consisted of 355 Japanese women with two or more consecutive pregnancy losses and 101 parous women. The frequency of PS-Tokushima and the subsequent live birth rate in relation to a PS deficiency defined as low PS-specific activity (total PS activity/total PS antigen) and the carriage of PS-Tokushima were examined. RESULTS AND CONCLUSIONS: There was no significant difference in the frequency of PS-Tokushima between patients and controls. The 8 patients carriers of PS-Tokushima variant were capable of a subsequent live birth without the use of heparin. There was no significant difference in subsequent live birth rates between patients with low or normal PS-specific activity/PS activity without heparin prophylaxis after excluding miscarriages caused by an abnormal embryonic karyotype using multivariate logistic regression analysis. There was no association between PS-Tokushima and RPL and a PS deficiency or low PS activity was shown not to serve as a reliable clinical predictor of subsequent miscarriage.

Genotyping analysis of the factor V Nara mutation, Hong Kong mutation, and 16 single-nucleotide polymorphisms, including the R2 haplotype, and the involvement of factor V activity in patients with recurrent miscarriage.

: Recurrent miscarriage can arise from a large diversity of causes and the factors responsible have not been fully clarified. The coagulation factor V R506Q (Leiden) mutation is a well known risk factor for recurrent miscarriage, although it has not been found in Japanese populations. We examined whether the factor V Nara and Hong Kong mutations, the factor V gene (F5) 16 single-nucleotide polymorphisms (SNPs), including the factor V R2 haplotype, and plasma factor V activity (FV:C) were risk factors for recurrent miscarriage. A cross-sectional study was conducted among 88 patients with a history of unexplained recurrent miscarriage and 95 fertile controls. None of the patients or controls was homozygous or heterozygous for the factor V Nara or Hong Kong mutation. In the 16 SNPs of F5, frequencies of the G/T and T/T genotypes at Ser156Ser were significantly lower in patients than in controls (OR 0.45, 95% CI 0.22-0.91, OR 0.32, 95% CI 0.14-0.72) and the allele frequency of C at Leu1288Leu was significantly higher in patients than that in controls (OR 1.66, 95% CI 1.02-2.71). The mean FV:C values were not significantly different between patients and controls. However, the prevalence of patients with a high or low FV:C (>95th or

Real-world practice of obstetricians in respect of assays for antiphospholipid antibodies.

OBJECTIVE: The international classification criteria (CC) for definite antiphospholipid syndrome (APS) recommend confirmation of the sustained presence, for at least 12 weeks, of both lupus anticoagulant (LA), as determined by aPTT and RVVT, and anti ß2glycoprotein I (ß2GPI) or anticardiolipin (aCL) IgG and/or IgM. However, it remains unclear whether obstetricians comply with the aforementioned CC for the diagnosis of APS in daily clinical practice. We performed a nationwide survey to examine the attitudes of Japanese obstetricians toward the use of assays for antiphospholipid antibodies (aPLs). METHODS: A questionnaire was sent to 2,700 obstetric facilities where maternity checkups are carried out. The types of assays conducted for aPLs, ascertainment of persistence of the antibodies for at least 12 weeks, and the cutoff points used for the assays were examined. RESULTS: Of the facilities surveyed, 61.5% carried out the assay(s) only once. In regard to the type of assay performed, 97.1% carried out the assay for aCL IgG and/or ß2GPI-dependent aCL, while 67.9% performed the LA-aPTT and/or LA-RVVT assay. Only 8.8% carried out assays for both LA. As for the cutoff points used, 98% of the facilities used lower cutoff points described in the manufacturers' manuals rather than the cutoff values recommended in the CC. CONCLUSION: Thus, only a limited number of facilities adhered precisely to the CC for the diagnosis of APS. Inappropriate treatment and unnecessary expense are potentially major concerns when facilities overdiagnose APS using lower cutoff points or without ascertaining the persistence of the antibodies for at least 12 weeks. On the other hand, some patients miss the opportunity to be treated for APS because of the absence of testing for LA.

Genotyping analysis for the 46 C/T polymorphism of coagulation factor XII and the involvement of factor XII activity in patients with recurrent pregnancy loss.

BACKGROUND: Established causes of recurrent pregnancy loss (RPL) include antiphospholipid syndrome, uterine anomalies, parental chromosomal abnormalities, particularly translocations and abnormal embryonic karyotype. A systematic review concluded that coagulation factor XII (FXII) deficiency was associated with RPL. However, it could not be established whether the 46 C/T SNP of FXII or low activity of FXII was a risk factor for RPL, because of the small sample size. METHODS AND FINDINGS: We conducted a cross-sectional and cohort study in 279 patients with two or more unexplained consecutive pregnancy losses and 100 fertile women. The association between the lupus anticoagulant (LA) activity and FXII activity was examined. The frequency of the CC, CT and TT genotypes and the FXII activity were also compared between the patients and controls. Subsequent miscarriage rates among the CC, CT, TT genotypes and according to the FXII activity was examined. LA was associated with reduced FXII activity. The CT, but not the TT, genotype was confirmed to be a risk factor for RPL in the cross-sectional study using multivariate logistic regression analysis (OR, 2.8; 95% CI, 1.37-5.85). The plasma FXII activity in the patients was similar to that in the controls. Neither low FXII activity nor the CT genotype predicted the subsequent pregnancy outcome in the cohort study. On the other hand, and intermediate FXII activity level of 85-101% was predictive of subsequent miscarriage. CONCLUSIONS: Low FXII activity was not associated with RPL. The FXII gene was found to be one of the significant susceptibility genes for RPL, similar to the FV Leiden mutation. However, the clinical influence of the CT genotype might be relatively small, because the presence/absence of this genotype did not have any predictive value for the subsequent pregnancy outcome. This was the first study indicating the influence of FXII 46C/T on further pregnancy outcomes.

Peripheral natural killer cell activity as a predictor of recurrent pregnancy loss: a large cohort study.

OBJECTIVE: To determine the predictive value of preconceptional peripheral blood natural killer (pNK) cell activity in patients with recurrent pregnancy loss (RPL). DESIGN: Cohort study. SETTING: University department. PATIENT(S): A total of 552 patients with a history of two to six consecutive miscarriages. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): The predictive value of preconceptional pNK cell activity for subsequent miscarriage was analyzed using multivariable logistic regression analysis, with age, number of previous miscarriages, and presence/absence of previous live births and bed rest as covariates. RESULT(S): Age and number of previous miscarriages, but not high pNK cell activity, were found to be independent risk factors for a subsequent miscarriage. No effect of bed rest and previous live birth on the likelihood of live birth was observed (odds ratios 1.28 [95% confidence interval 0.81-2.02] and 0.91 [0.52-1.59], respectively). CONCLUSION(S): Elevated pNK cell activity was found to not be an independent risk factor for subsequent miscarriage. Clinicians should not measure the plasma NK activity as a systematic recurrent pregnancy loss examination, because its clinical significance is yet to be established.