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Background: Autologous blood donation for placental malposition is common in Japan, but no studies have scientifically evaluated its usefulness. The purpose of this study was to evaluate the necessity for autologous blood donation for placental malposition. Methods: A retrospective study was conducted of patients who underwent autologous blood donation for placental malposition at Kindai University Hospital from 2012 to 2022. The primary outcome was the proportion of patients who were able to avoid allogeneic blood transfusion by autologous blood transfusion; secondary outcomes were autologous blood disposal rate, allogeneic blood transfusion rate, and complications of autologous blood donation and allogeneic blood transfusion. A systematic review of studies on autologous blood transfusion for placental malposition was conducted on PubMed. Results: Fifty-two patients (total placenta previa 16; marginal placenta previa 20; low-lying placenta 16) were included. Eight (15%) had complications at the time of autologous blood donation, including non-reassuring fetal heart rate, but no sequelae. Allogeneic blood transfusion was avoided by autologous blood transfusion in only five cases (9.6%). Autologous blood was discarded in nine cases (17%), seven of which had a low-lying placenta positioned normally at delivery. Allogeneic blood transfusion was performed in eight cases (15%) with no complications. In the systematic review, seven articles that met the inclusion criteria were selected for further evaluation. The results showed that there were no publications that scientifically demonstrated the benefit of autologous blood transfusion. Conclusions: The results of this study indicate that autologous blood donation for placental malposition has little benefit. [ABSTRACT FROM AUTHOR]

Aim: We aimed to investigate the associations of endometriosis and adenomyosis with pregnancy complications by using a large‐scale Japanese database. Methods: We retrospectively analyzed 145 590 singleton pregnancies from the Japan Perinatal Registry Network Database. Pregnant women registered as having endometriosis or adenomyosis were designated as the case group (EA), whereas the control group (non‐EA) was selected using propensity‐score matching adjusted for variables such as age, parity, BMI, smoking history, and the use of assisted reproductive technology. The main outcomes included placental malposition, preterm birth, and hypertensive disorders of pregnancy (HDP). Results: In total, 1203 patients from both the EA and non‐EA groups were matched and evaluated. The EA group showed significantly higher rates of placenta previa (odds ratio [OR], 3.01; 95% confidence interval [CI], 1.84–4.92), low‐lying placenta (OR, 2.02; 95% CI, 1.06–3.86), and preterm birth (OR, 1.44; 95% CI, 1.13–1.84) than the non‐EA group. However, no significant difference was observed in the incidence of HDP (OR, 1.22; 95% CI, 0.90–1.66). Conclusion: The use of propensity‐score matching to analyze a nationwide perinatal database in Japan clarified that EA was associated with increased pregnancy complications, specifically placental malposition, including placenta previa and low‐lying placenta, and preterm birth, but not with HDP. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the association between adenomyosis and placenta accreta spectrum (PAS) and to evaluate the effect of assisted reproductive technology (ART) in mediating this association., Methods: We retrieved data for singleton women from the Japanese nationwide perinatal registry between 2013 and 2019, excluding women with a history of adenomyomectomy. To investigate the association between adenomyosis and PAS among women, we used a multivariable logistic regression model with multiple imputation for missing data. We evaluated mediation effect of ART including in vitro fertilization and intracytoplasmic sperm injection on the association between adenomyosis and PAS using causal mediation analysis based on the counterfactual approach., Results: Of 1 500 173 pregnant women, 1539 (0.10%) had adenomyosis. The number receiving ART was 489/1539 (31.8%) and 117 482/1 498 634 (7.8%) in women with and without adenomyosis, respectively. The proportion of women who developed PAS was 21/1539 (1.4%) in women with adenomyosis and 7530/1 498 634 (0.5%) in women without adenomyosis. Adenomyosis was significantly associated with PAS (odds ratio [OR] 1.95; 95% confidence interval [CI] 1.26-3.00; P = 0.002). Mediation analysis showed that OR of the total effect of adenomyosis on PAS was 1.98 (95% CI 1.13-3.04), OR of natural indirect effect (effect explained by ART) was 1.15 (95% CI 1.01-1.41), and OR of natural direct effect (effect unexplained by ART) was 1.72 (95% CI 0.86-2.82). The proportion mediated (natural indirect effect/total effect) was 26.5%. Adenomyosis was also significantly associated with PAS without previa (OR 1.96; 95% CI 1.23-3.13, P = 0.005)., Conclusion: Adenomyosis was significantly associated with PAS. ART mediated 26.5% of the association between adenomyosis and PAS., (© 2024 International Federation of Gynecology and Obstetrics.)

Intrapartum fetal heart rate monitoring abnormalities had been reported to correlate with decreased umbilical artery base excess associated with neonatal seizures. However, we present an infant born at 35 weeks of gestation diagnosed with cerebral palsy associated with periventricular leukomalacia (PVL) without fetal heart rate (FHR) monitoring abnormalities, According to the summary reports of PVL cases published on the home page of the Japan Obstetric Compensation System for Cerebral Palsy (JOCSC)), the percentage of placenta previa without FHR monitoring abnormalities in the cases of PVL was 5.7% (12/209), which seemed to be higher than the total percentage of placenta previa reported in Japan (0.3-0.5%)., Competing Interests: No competing interests were disclosed., (Copyright: © 2024 Suzuki S.)

Introduction: Massive hemorrhage due to placenta previa with placenta accreta spectrum is associated with high maternal mortality and morbidity. Therefore, accurate prediction of placenta previa with placenta accreta spectrum is essential; magnetic resonance imaging (MRI) is a useful tool for this purpose. This study investigated novel predictors of anterior and posterior placenta previa with placenta accreta spectrum using MRI. Material and methods: This was a retrospective study at a tertiary obstetrics hospital in Japan. The singleton patients with placenta previa who were scanned with MRI prenatally and had a cesarean section at our institution between 2007 and 2018 were included. The prediction of anterior and posterior placenta previa with placenta accreta spectrum was evaluated using four MRI findings: heterogeneous signals in the placenta, dark T2‐weighted intraplacental bands, myometrial thinning or interruption, and focal uterine bulging. The prediction of posterior placenta previa with placenta accreta spectrum was performed using the quantification of cervical varicosities, which were defined as the ratio of the distance between the minimum distance from the most dorsal cervical varicosities (a) to the deciduous and amniotic placenta (b) on a sagittal image. Results: Among 202 patients, 14 (6.9%) patients were pathologically diagnosed as having placenta accreta spectrum. Further, 38 (18.8%) patients had anterior placenta previa and 164 (81.2%) patients had posterior placenta previa. When anterior placenta previa with placenta accreta spectrum was predicted using at least one of the four MRI findings, the sensitivity and specificity of the anterior placenta previa with placenta accreta spectrum were 87.5% and 86.7%, respectively. In contrast, the sensitivity and specificity of posterior placenta previa with placenta accreta spectrum were 42.9% and 96.2%, respectively. But when the A/B ratio was set at 0.20, the sensitivity and specificity of the prediction for posterior placenta previa with placenta accreta spectrum using cervical varicosities were 100.0% and 89.2%, respectively. Conclusions: The findings of MRI to predict the anterior placenta previa with placenta accreta spectrum were different from posterior placenta previa. The cervical varicosities may be useful in predicting posterior placenta previa with placenta accreta spectrum. [ABSTRACT FROM AUTHOR]

Aim: This study aimed to clarify ultrasound screening and management for vasa previa (VP) in perinatal centers and primary facilities in Japan. Methods: A questionnaire survey about antepartum ultrasound screening and management for VP was delivered in 2018. Questions were sent by email or post to perinatal centers and randomly selected primary hospitals or clinics throughout Japan. Results: Seventy‐seven perinatal centers and 300 primary facilities answered. VP was screened in 85.7% of perinatal centers and 81.3% of primary facilities. The reported incidence of VP was 0.05% (86/158 323) and 0.05% (28/54 791) in perinatal centers and primary facilities, respectively. When patients were diagnosed with VP, 88.7% of primary facilities referred the patient to a tertiary hospital. Routine hospitalization (100%) and steroid administration (46%) were frequently performed in perinatal centers. The median gestational age at planned cesarean section was significantly earlier in perinatal centers (34 weeks) than in primary facilities (37 weeks). Of the 31 reported cases of VP, 30 were reported as intact survival, but 1 case required an emergency cesarean section at 38 weeks of gestation without an antenatal diagnosis, resulting in neonatal death. Conclusion: More than 80% of obstetric facilities both perinatal centers and clinics in Japan perform ultrasound screening with for VP with similar detection rate. However, to further improve perinatal outcomes related to VP, pathophysiology and diagnosis of VP should be more widely recognized by obstetric caregivers throughout Japan. [ABSTRACT FROM AUTHOR]

Objective: To investigate maternal outcomes after leaving the placenta in situ for placenta accreta spectrum (PAS) disorders in patients with placenta previa on a cesarean delivery scar.Methods: The present retrospective study reviewed medical records from women with placenta previa on a cesarean scar underwent perinatal care at secondary- or tertiary-level perinatal centers in Japan between January 1, 2010, and December 31, 2014. Perinatal management was conducted based on each leading obstetrician's discretion. The primary outcome was success of the leaving the placenta in situ approach for PAS disorders (defined as preserving the uterus without hysterectomy).Results: Of 178 eligible centers, 126 (71%) participated in this study; data from 613 patients were included. Of these, 41 had the placenta left in situ owing to PAS disorders and follow-up data were available for 36 women. Leaving the placenta in situ was successful in 25 (69%) patients, with placental resorption occurring postpartum (median 89 days; range 6-510). Hysterectomy was performed for 11 patients, primarily owing to hemorrhage and/or infection (median 30 days; range 0-95 days, postpartum).Conclusion: Leaving the placenta in situ, with close postpartum follow-up for at least several months, could be a uterus-preserving option for patient with PAS disorders. [ABSTRACT FROM AUTHOR]

Aim: To assess the usefulness of a new method for cesarean section (CS) that is comprised of a transverse incision into the uterine fundus, developed for women with placentas covering the entire anterior uterine wall, and introduced in September 2006. Material and Methods: Review of medical records of 12 and 29 women who underwent CS by the new and conventional methods, respectively, for placenta previa, placenta accreta (accreta, increta and percreta) or placenta widely covering the entire anterior uterine wall in which placenta accreta cannot be excluded, between June 2003 and March 2011. Results: Placenta accreta (67% [8/12] vs 10% [3/29], P = 0.0006) and cesarean hysterectomy (67% vs 10%) were significantly more frequent in the group with the new compared with the conventional method. There were no significant differences between groups with the new and conventional methods in amount of blood loss (1732 ± 1067 vs 1847 ± 1279 g, respectively), prevalence of blood loss >3000 g (8.3% vs 17%, respectively) or blood transfusion (92% vs 72%, respectively), time required for cesarean hysterectomy (210 ± 58 vs 195 ± 41 min), or neonatal conditions at birth. The amount of blood loss for cesarean hysterectomy was significantly less for the new than conventional method (1959 ± 1025 g vs 4450 ± 1145 g, P = 0.041). Conclusion: The new method was superior to the conventional method with respect to reduction of blood loss during cesarean hysterectomy. However, careful observations are mandatory in women with preserved uterus with respect to a possible increased risk of uterine rupture in future pregnancies. [ABSTRACT FROM AUTHOR]

Background and Objectives: There are no reports showing the hematopoietic effect of TJ-108 on pregnant women. The aim of this study was to investigate the effect of TJ-108 on the hemoglobin and hematocrit levels, and white blood cell and platelet counts of pregnant women complicated with placenta previa who were managed with autologous blood storage for cesarean section. Materials and Methods: We studied two groups of patients who were complicated with placenta previa and who underwent cesarean delivery. Group A consisted of women who were treated with oral iron medication (100 mg/day), and Group B consisted of women who were treated with TJ-108 at a dose of 9.0 g per day, in addition to oral iron medication, from the first day of blood storage until the day before cesarean delivery. To evaluate the effect of TJ-108, the patients' red blood cell (RBC); Hb; hematocrit (Ht); white blood cell (WBC); and platelet count (PLT) levels were measured 7 days after storage and at postoperative days (POD) 1 and 5. Results: The study included 65 individuals, 38 in group A and 27 in group B. At the initial storage, a 0.2 g/dL reduction in Hb levels was observed, as compared to the initial Hb levels, in the TJ-108 treated patients, whereas a 0.6 g/dL reduction in Hb levels was observed in the non-TJ-108 treated group. On the other hand, regarding the second and subsequent storages, no significant difference was found in the decrease in the Hb levels of both groups. Conclusions: This study is the first report showing the effect of TJ-108 on improving anemia in pregnant women, presumably by its boosting effect on myelohematopoiesis. Therefore, the combined administration of both iron and TJ-108 is effective as a strategy for pregnant women at a high risk of PPH due to complications such as placenta previa.

A 37-year-old primigravida at 35 weeks of gestation presented with known anterior wall dominant placenta previa totalis and suspected placenta accreta was successfully treated with transfundal uterine (transverse) incision performed with prophylactic common iliac artery balloon occlusion. This new surgical approach could be an alternative procedure for avoiding excessive blood loss during caesarean delivery. [ABSTRACT FROM AUTHOR]

Aim: To investigate the association between the amount of bleeding during a cesarean section and the effacement of the uterine cervix in patients with placenta previa. Methods: This study reviewed 115 singleton pregnancies with placenta previa. In cases of placenta previa, the thickness of the uterine muscle and cervical length were retrospectively measured and compared with the amount of bleeding during the cesarean section. Results: No correlation was found between the amount of bleeding during the cesarean operation and the thickness of the uterine isthmus. Therewas a significantly negative correlation between the amount of bleeding and cervical length (r = -0.344, P < 0.001). The threshold cervical length associated with massive bleeding (>2500 mL) was 25 mm, based on an ROC curve. The relative risk for massive bleeding in cases with a short cervical length (<25 mm) was 7.2 (95% CI, 2.3–22.3) in comparison to cases with a long cervical length. Conclusions: This study demonstrated that a short cervical length in cases with placenta previa was associated with massive bleeding during the operation. Short cervical length seems to be one of the warning signs for massive bleeding during the operation for placenta previa. [ABSTRACT FROM AUTHOR]

Aim: The effect of placenta previa on age-specific placental size has not yet been elucidated. This study aimed to examine the effect of placenta previa on the Japanese standardized z-scores of placental size., Methods: This retrospective cohort study included Japanese participants from Ohta Nishinouchi Hospital with single pregnancies who gave birth during 2013-2019. The participants were categorized into two groups based on the presence or absence of placenta previa. Multiple linear regression analyses were used to identify the association of placenta previa with the z-score of placental size, after adjusting for factors, such as maternal smoking status, maternal age, assisted reproductive technology, myoma uteri, uterine anomaly, maternal hypertension at the time of pregnancy, and body mass index before pregnancy., Results: A total of 4071 Japanese women (76 with placenta previa and 3995 without placenta previa) were identified. Placenta previa significantly increased the placental weight z-score (partial regression coefficient: 0.44, 95% confidence interval 0.10-0.70, p < 0.001)., Conclusion: Placenta previa increased the age-specific placental size. Further studies are required to examine whether placenta previa is associated with the risk of obstetrics complications related to the placental size., (© 2021 Japan Society of Obstetrics and Gynecology.)

Introduction: With increasing caesarean section (c-section) rates, personalized communication of risk has become paramount. A reliable tool to predict complications would support evidence-based discussions around planned mode of birth. This systematic review aimed to identify, synthesize and quality appraise prognostic models of maternal complications of elective c-section., Methods: MEDLINE, Embase, Web of Science, CINAHL and the Cochrane Library were searched on 27 January using terms relating to 'c-section', 'prognostic models' and complications such as 'infection'. Any study developing and/or validating a prognostic model for a maternal complication of elective c-section in the English language after January 1995 was selected for analysis. Data were extracted using a predetermined checklist: source of data; participants; outcome to be predicted; candidate predictors; sample size; missing data; model development; model performance; model evaluation; results; and interpretation. Quality was assessed using the Prediction model Risk Of Bias ASsessment Tool (PROBAST) tool., Results: In total, 7752 studies were identified; of these, 16 full papers were reviewed and three eligible studies were identified, containing three prognostic models derived from hospitals in Japan, South Africa and the UK. The models predicted risk of blood transfusion, spinal hypotension and postpartum haemorrhage. The study authors deemed their studies to be exploratory, exploratory and confirmatory, respectively. From the three studies, a total of 29 unique candidate predictors were identified, with 15 predictors in the final models. Maternal age (n = 3), previous c-section (n = 2), placenta praevia (n = 2) and pre-operative haemoglobin (n = 2) were found to be common predictors amongst the included studies. None of the studies were externally validated and all had a high risk of bias due to the analysis technique used., Conclusion: Few models have been developed to predict complications of elective c-section. Existing models predicting blood transfusion, spinal hypotension and postpartum haemorrhage cannot be recommended for clinical practice. Future research should focus on identifying predictors known before surgery and validating the resulting models., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Objectives: This study aimed to identify intrauterine growth differences according to infertility treatment compared with spontaneous conception and to describe intrauterine growth trajectories., Design: Retrospective cohort study., Setting: A single primary and tertiary medical centre in Japan., Participants: This study included singleton pregnant women with prenatal check-ups and delivery at the University of Yamanashi Hospital between 1 July 2012 and 30 September 2017. Patients were divided into four groups: spontaneous conception, infertility treatment without assisted reproductive technology (ART), fresh-embryo transfer and frozen embryo transfer (FET)., Interventions: Differences in intrauterine growth according to the infertility treatment, including ART, and birth weight were evaluated. Multilevel analysis was employed to evaluate intrauterine growth trajectories stratified by the sex of the offspring., Primary Outcome Measure: Estimated fetal weight (EFW) assessed by ultrasound examination., Results: We assessed data from 37 239 prenatal examination results from 2377 pregnant women (spontaneous conception, n=1764; infertility treatment without ART, n=171; fresh-embryo transfer, n=112; and FET, n=330) in the final analysis. Multilevel analysis was adjusted for gestation duration, gestation period, parity, hypertensive disorders of pregnancy, type of infertility treatment, maternal age, smoking status, placenta previa, thyroid disease, gestational diabetes mellitus and the interaction between each potential confounding factor and gestation duration. In male fetuses, the interaction between FET and gestational duration (estimate: 0.36; 95% CI: 0.06 to 0.67) significantly affected the EFW. Similarly, in female fetuses, FET (estimate: -69.85; 95% CI: -112.09 to -27.61) and the interaction between FET and gestation duration (estimate: 0.57; 95% CI: 0.28 to 0.87) significantly affected the EFW., Conclusions: This study shows that FET affects intrauterine growth trajectory from the second trimester to term, particularly in female fetuses. Our findings require further prospective research to examine the effect of infertility treatment on fetal growth., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

The Japan Environment Health and Children's Study (JECS) is an ongoing cohort study designed to evaluate the impact of various environmental factors on children's health. In this study, more than 100,000 pregnant women were recruited in 15 regional centers throughout Japan. Within the University of Occupational and Environmental Health, the departments of Pediatrics, Obstetrics and Gynecology, Environmental Health, and the School of Health Sciences collaborate with the JECS University of Occupational and Environmental Health Subunit Center in advancing research in this study. Several original articles based on JECS and written by our unit members were published in recent years. The aim of this review is to summarize these studies by JECS and University of Occupational and Environmental Health Subunit Center based on the data from JECS. We introduce research articles covering the following categories; environmental health, occupational health, and maternal and child health. Studies found associations between concentrations of metals and maternal health, such as premature birth, placenta previa and placenta accrete, associations between metals and IgE, dietary differences among occupational groups, associations between work-related factors and dietary behaviors, associations between job changes and pregnancy/delivery, mental and physical stress among pregnant women and influence on work, associations between sleep and gestational diabetes, and associations between an ability to push up in the prone position and infant development. This review may promote the development of new research, such as collaborative research projects, including clinical and social medicine, epidemiological studies and laboratory investigations.

Background: Placenta accreta spectrum (PAS) is a life-threating complication in the field of obstetrics. Sometimes we face with unexpected PAS cases which is potentially higher maternal mortality and morbidity compared with expected cases. The present study was conducted to examine the prevalence of PAS and to elucidate its risk factors using a large Japanese birth cohort study., Methods: We reviewed the results of a nationwide prospective birth cohort study in Japan, and identified 90,554 participants treated from 2011 to 2014 in 15 regional centers. Multiple regression models were created to identify the risk factors for PAS. These data were obtained from self-reported questionnaires or patient medical records., Results: This analysis consisted of 202 cases of PAS (18 with placenta previa and 184 without placenta previa) and 90,352 cases without PAS. The multiple logistic regression analysis showed that placenta previa (adjusted odds ratio [aOR]: 12.86, 95% confidence interval [CI] 7.70-21.45, P < 0.001), assisted reproductive technology-related pregnancies (aOR: 6.78, 95% CI 4.54-10.14, P < 0.001), smoking during pregnancy (aOR: 1.95, 95% CI 1.15-3.31, P = 0.013), more than two previous cesarean sections (aOR: 2.51, 95% CI 1.35-4.67, P = 0.004), and uterine anomalies (aOR: 3.97, 95% CI 1.24-12.68, P = 0.020) increased the risk of PAS., Conclusion: In general population, placenta previa, assisted reproductive technology-related pregnancy, smoking during pregnancy, repeated cesarean sections, and uterine anomalies were risk factors for PAS in the Japanese population.

Background: Endometriosis is a common disease occurring in 1-2% of all women of reproductive age. Although there is increasing evidence on the association between endometriosis and adverse perinatal outcomes, little is known about the effect of pre-pregnancy treatments for endometriosis on subsequent perinatal outcomes. Thus, this study aimed to evaluate maternal and neonatal outcomes in pregnant women with endometriosis and to investigate whether pre-pregnancy surgical treatment would affect these outcomes., Methods: This case-control study included 2769 patients who gave birth at Nagoya University Hospital located in Japan between 2010 and 2017. Maternal and neonatal outcomes were compared between the endometriosis group (n = 80) and the control group (n = 2689). The endometriosis group was further divided into two groups: patients with a history of surgical treatment such as cystectomy for ovarian endometriosis, ablation or excision of endometriotic implants, or adhesiolysis (surgical treatment group, n = 49) and those treated with only medications or without any treatment (non-surgical treatment group, n = 31)., Results: In the univariate analysis, placenta previa and postpartum hemorrhage were significantly increased in the endometriosis group compared to the control group (12.5% vs. 4.1%, p <  0.01 and 27.5% vs. 18.2%, p = 0.04, respectively). In the multivariate analysis, endometriosis significantly increased the odds ratio (OR) for placenta previa (adjusted OR, 3.19; 95% confidence interval [CI], 1.56-6.50, p <  0.01) but not for postpartum hemorrhage (adjusted OR, 1.14; 95% CI, 0.66-1.98, p = 0.64). Other maternal and neonatal outcomes were similar between the two groups. In patients with endometriosis, patients in the surgical treatment group were significantly associated with an increased risk of placenta previa (OR. 4.62; 95% CI, 2.11-10.10, p <  0.01); however, patients in the non-surgical treatment group were not associated with a high risk (OR, 1.63; 95% CI, 0.19-6.59, p = 0.36). Additionally, other maternal and neonatal outcomes were similar between the two groups., Conclusion: Women who have had surgical treatment for their endometriosis appear to have a higher risk for placenta previa. This may be due to the more severe stage of endometriosis often found in these patients. However, clinicians should be alert to this potential increased risk and manage these patients accordingly.

Background: Placenta previa and placenta accreta associate with high morbidity and mortality for both mothers and fetus. Metal exposure may have relationships with placenta previa and placenta accreta. This study analyzed the associations between maternal metal (cadmium [Cd], lead [Pb], mercury [Hg], selenium [Se], and manganese [Mn]) concentrations and placenta previa and placenta accreta., Methods: We recruited 17,414 women with singleton pregnancies. Data from a self-administered questionnaire regarding the first trimester and medical records after delivery were analyzed. Maternal blood samples were collected to measure metal concentrations. The subjects were classified into four quartiles (Q1, Q2, Q3, and Q4) according to metal concentrations., Results: The odds ratio for placenta previa was significantly higher among subjects with Q4 Cd than those with Q1 Cd. The odds ratio for placenta previa was significantly higher for subjects with Q2 Pb than those with Q1 Pb., Conclusion: Participants with placenta previa had higher Cd concentrations. However, this study was cross-sectional and lacked important information related to Cd concentration, such as detailed smoking habits and sources of Cd intake. In addition, the subjects in this study comprised ordinary pregnant Japanese women, and it was impossible to observe the relationship between a wide range of Cd exposure and placenta previa. Therefore, epidemiological and experimental studies are warranted to verify the relationship between Cd exposure and pregnancy abnormalities.

Objective: The current definition of placenta previa does not include whether the placental edge is parenchyma or marginal sinus defined as placenta previa in which the placental marginal sinus just reached the internal os and/or in which the placental parenchyma might be located at > 2 cm from internal os., Materials and Methods: Cases with placenta previa were identified through the review of magnetic resonance imaging (MRI) from among 210 cases at our institution between 2007 and 2016. The clinical outcomes of patients with marginal sinus placenta previa (Group A) were compared with patients with low-lying placenta and marginal placenta (Group B) and patients with partial placenta and total placenta previa (Group C), respectively. This study was a retrospective analysis., Results: Twenty-seven (12.7%) cases were included in Group A. The patients in Group B and Group C were 72 and 108 cases, respectively. First, Group A more frequently underwent emergency cesarean section than Group B (p = 0.02). There was no statistical significance with other maternal history, post-or pre-operative hemorrhage, and/or additional treatment for hemorrhage between the two groups. Additionally, Group A delivered at a later gestational age (p < 0.01); were less frequently complicated with antenatal bleeding (p < 0.01); underwent emergency cesarean section (p < 0.01), allogenic blood transfusion (p < 0.01), and uterine artery embolization (p < 0.01) for postpartum hemorrhage less often; and had less perioperative hemorrhage (p < 0.01) than Group C., Conclusions: Marginal sinus placenta previa may be a mild type of placenta previa. This new classification could be useful in the management of placenta previa., (Copyright © 2018. Published by Elsevier B.V.)