Publications by authors named "Masahiko Nakata"

Introduction: Preeclamptic patients, both lean and obese, present with elevated leptin levels which are associated with the development of maternal endothelial dysfunction and adverse fetal outcomes, such as growth restriction, leading to low birth weight. Recent studies in pregnant mice demonstrate that mid-late gestation leptin infusion induces clinical characteristics of preeclampsia, including elevated maternal blood pressure, maternal endothelial dysfunction and fetal growth restriction. However, whether leptin triggers placental stress responses that contribute to adverse fetal outcomes as in preeclampsia is unknown.

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  • * Out of 272 twin pairs, the survival rates were very high, with 98% of at least one twin surviving and 85% for both, while 93% of recipient twins and 90% of donor twins survived.
  • * The research identifies preoperative anemia-polycythemia sequence and arterio-arterial vascular anastomosis (AAA) as significant risk factors for mortality in donor twins after FLP, although the exact mechanisms of AAA need further investigation.
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  • The study aimed to evaluate the hemodynamics of twin-to-twin transfusion syndrome (TTTS) by measuring intraventricular pressure difference (IVPD) using fetal echocardiography in monochorionic diamniotic twins.
  • Twenty-eight twins diagnosed with TTTS underwent fetoscopic laser photocoagulation (FLP), and their cardiac IVPD was assessed before and after the procedure, revealing significant increases in IVPD in both the recipient and donor twins' left ventricles.
  • The findings suggest that IVPD is a sensitive indicator of changes in myocardial function and could be valuable for monitoring heart issues in TTTS cases.
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Objectives: To clarify the infection route in maternal death due to invasive group A streptococcal (GAS) infection and toxic shock syndrome (TSS).

Methods: A retrospective study was conducted on maternal deaths due to GAS-TSS in Japan between January 2010 and March 2024. The final causal diagnosis of maternal death and the infection routes of GAS were analysed using medical records, laboratory data and autopsy findings.

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Chronic endometritis (CE), an inflammatory condition characterized by plasma cell infiltration within the endometrial stroma, is prevalent among women experiencing unexplained infertility or recurrent miscarriages. CE is traditionally diagnosed by endometrial biopsy using CD138 immunohistochemistry staining. Despite some studies suggesting hysteroscopy as an alternative diagnostic tool, its reliability compared with biopsy remains controversial.

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Introduction: Our objective was to investigate the association between the presence of placental anastomoses and intertwin differences in renin-angiotensin-aldosterone activation in monochorionic twins using amniotic fluid aldosterone (AF-ALD) levels. In addition, this study also examined the association between AF-ALD and the ALD levels in the umbilical cord blood (UCB-ALD) in monochorionic twins.

Material And Methods: This prospective study included monochorionic diamniotic (MD) twin pregnancies that were not complicated by twin-to-twin transfusion syndrome (TTTS) at delivery.

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Background: The iPREFACE score may aid in predicting fetal acidemia and neonatal asphyxia in emergency cesarean and vaginal deliveries, which may improve labor management precision in the future.

Objective: This study aimed to assess the score use of the iPREFACE as an objective indicator of the need for rapid delivery in cases of repeated abnormal waveforms without concurrent indications for immediate medical intervention during labor.

Study Design: This retrospective cohort study was conducted among term (37+ 0 days to 41+6 days) singleton pregnant women who underwent emergency cesarean delivery owing to a nonreassuring fetal status.

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  • The study aimed to evaluate the safety of long-term use of ritodrine hydrochloride, a tocolytic agent used in Japan for treating threatened preterm labor, particularly its link to maternal deaths.
  • It analyzed data from 390 maternal death cases from 2010 to 2020, revealing that 32 involved the administration of ritodrine, with specific doses and routes documented.
  • The findings indicated higher instances of serious health issues like perinatal cardiomyopathy and pulmonary edema in patients who received ritodrine, suggesting a potential risk associated with its long-term use during pregnancy.
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Purpose: This study aimed to evaluate the effects of swim-up and density gradient centrifugation methods on sperm DNA fragmentation.

Methods: Nineteen normozoospermic patient samples with ≥100 × 10 motile sperms were included in this study. Sperm DNA fragmentation, progressive motility, and progressive motile sperm number were measured before and after the swim-up method or density gradient centrifugation.

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Background: The failure of frozen-thawed blastocysts to re-expand adequately within a few hours after warming has been reported to have a negative impact on assisted reproductive technology (ART) outcomes. However, the extent to which this failure truly affects ART outcomes has not yet been presented in a manner that is easily understandable to medical practitioners and patients. This study aimed to assess the effects of blastocyst shrinkage on ART outcomes and determine a more effective morphological evaluation approach for use in clinical settings.

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  • * The research found that women aged 40 years and older had a significantly higher maternal mortality rate (11.2 per 100,000) compared to younger age groups, with hemorrhagic stroke being the leading cause of death in this demographic.
  • * The findings highlighted that over half of the hemorrhagic strokes in older pregnant women were linked to hypertension disorders during pregnancy, emphasizing the importance of perinatal care for women choosing to have children later in life.
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Fertility preservation (FP) for hematological malignancies is difficult because immediate chemotherapy is needed after diagnosis. We report two cases of acute myeloid leukemia (AML) treated with controlled ovarian stimulation (COS) and oocyte cryopreservation using DuoStim after first-line chemotherapy. In Cases 1 and 2, COS and oocyte retrieval (OR) were performed using DuoStim 116 and 51 days after first-line chemotherapy, respectively, and 14 and 6 unfertilized oocytes, respectively, were cryopreserved.

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Background: mRNA vaccination is an effective, safe, and widespread strategy for protecting pregnant women against infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, information on factors such as perinatal outcomes, safety, and coverage of mRNA vaccinations among pregnant women is limited in Japan. Therefore, this study aimed to investigate the perinatal outcomes, coverage, adverse effects, and short-term safety of mRNA vaccination as well as vaccine hesitancy among pregnant women.

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Background: Unlike Europe and the United States, Japan has seen numerous maternal deaths from hemorrhagic strokes related to hypertensive disorders of pregnancy (HDP). This study retrospectively analyzed deaths associated with HDP-related hemorrhagic stroke in Japan to determine the number of deaths that may have been prevented with blood pressure control during pregnancy.

Methods: This study included maternal deaths related to hemorrhagic stroke cases.

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  • * Many patients exhibited symptoms like pain and respiratory issues, with a significant portion having known risk factors such as advanced age and hypertension.
  • * The findings indicate a need for better cardiac risk assessment and care quality, emphasizing the importance of awareness and a team approach among healthcare providers to prevent maternal deaths due to CVD.
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The 2017 clinical guidelines for obstetrical practice by the Japan Society of Obstetrics and Gynecology and the Japan Association of Obstetricians and Gynecologists were revised and published as the 2020 edition (in Japanese). The aim of these guidelines is to present appropriate standard obstetric diagnosis and management procedures that have reached consensus among Japanese obstetricians. The 2020 guidelines include 113 clinical questions and an appendix, followed by answers (CQ&A; originally 112 in the 2017 edition), a discussion, list of references, and some tables and figures presenting common problems and questions encountered in obstetrical practice.

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Objective: To investigate the differences in amniotic fluid cardiac biomarkers and clinical features among types of right ventricular outflow tract (RVOT) abnormality in monochorionic (MC) twins.

Method: This prospective study included MC twins that underwent laser surgery. Recipient or larger twins (group A) and donor or smaller twins (group B) were assessed and divided into those with a normal right ventricular outflow tract (normal RVOT), functional pulmonary atresia (fPA), or pulmonary stenosis (PS).

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  • The study assessed the effectiveness of cardiotocography (CTG) in predicting fetal acidemia during labor, focusing on the optimal assessment duration using the iPREFACE scoring system.
  • Conducted at Toho University Omori Medical Center, the research analyzed data from 325 full-term vaginal deliveries, ultimately including 145 patients after excluding those with incomplete CTG results.
  • Findings indicated that the iPREFACE scores significantly correlated with umbilical artery blood pH levels, with the 30-minute assessment (iPREFACE(30)) showing the best predictive capacity for identifying fetal acidemia.
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Multiple pregnancies pose a high risk of morbidity and mortality in both mothers and infants; thus, obtaining reliable information based on a large population is essential to improve management. We used the maternal and child health statistics, which are published annually, from the database of the Ministry of Health, Labor, and Welfare. The data obtained were aggregated in 5-year intervals, and we used them to analyze the proportion of the number of births for each week of pregnancy to the total of each singleton and multiple pregnancy.

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  • The study explored the connection between Doppler ultrasound measurements and levels of a specific cardiac biomarker (afNT-proBNP) in twin pregnancies affected by twin-to-twin transfusion syndrome (TTTS).
  • Researchers focused on monochorionic diamniotic twin pairs undergoing fetoscopic laser surgery, measuring various blood flow parameters in the twins.
  • Results showed a strong correlation between the Doppler pulsatility index of the ductus venosus and biomarker levels in recipient twins, indicating the ductus venosus could serve as a noninvasive indicator of increased cardiac load in these cases.
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Introduction: TheTADAlafil treatment for Fetuses with early-onset growth Restriction: multicentrer, randomizsed, phase II trial (TADAFER II) study showed the possibility of prolonging the pregnancy period in cases of early-onset fetal growth restriction; however, it was an open-label study. To establish further evidence for the efficacy of tadalafil in this setting, we planned a multicentre, randomised, placebo-controlled, double-blind trial.

Methods And Analysis: This trial will be conducted in 180 fetuses with fetal growth restriction enrolled from medical centres in Japan; their mothers will be randomised into three groups: arm A, receiving two times per day placebo; arm B, receiving one time per day 20 mg tadalafil and one time per day placebo and arm C, receiving 20 mg two times per day tadalafil.

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Sudden unexpected death in epilepsy (SUDEP) is defined as the sudden death of a patient with epilepsy in the absence of an anatomic or toxicologic cause. Whether pregnancy is a risk factor for SUDEP is unclear. Using data submitted to the Japan Association of Obstetricians and Gynecologists (JAOG), which has been collating information regarding all maternal deaths in Japan since 2000, this study evaluated maternal mortality data from 2010 to 2019 to evaluate the current circumstances of maternal death related to SUDEP in Japan.

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Aim: The purpose of this study was to investigate the outcomes of fetoscopic laser photocoagulation (FLP) for twin-to-twin transfusion syndrome (TTTS) in Japan.

Methods: The retrospective cohort study (2012-2018) was conducted in monochorionic twin pregnancies that underwent FLP for TTTS between 26 and 27 weeks from 2012 to 2018. The perioperative data, maternal complications, gestational age (GA) at delivery, neonatal complications, and survival of infants at 28 days of age were analyzed.

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Objective: The purpose of this study was to retrospectively examine the use of lung-to-liver signal intensity ratio (LLSIR) on T2-weighted images to predict functional pulmonary hypoplasia.

Methods: The subjects of this study were pregnant women who underwent magnetic resonance imaging (MRI). Patients who required nitric oxide inhalation and those who died from respiratory disorders were classified as having functional pulmonary hypoplasia (FPH).

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