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Dive into the research topics where Naoto Yonetani is active.

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Featured researches published by Naoto Yonetani.


Fetal Diagnosis and Therapy | 2015

Significance of Velamentous Cord Insertion for Twin-Twin Transfusion Syndrome

Naoto Yonetani; Keisuke Ishii; Hiroshi Kawamura; Aki Mabuchi; Shusaku Hayashi; Nobuaki Mitsuda

Introduction: The objective of this study was to evaluate the actual association between velamentous cord insertion (VCI) and twin-twin transfusion syndrome (TTTS) in the native cohort concerning the natural history of monochorionic twin pregnancies. Material and Methods: All monochorionic diamniotic twin pregnancies who received prenatal care from <16 weeks of gestation until delivery at our center between 2004 and 2013 were included in this retrospective cohort study. Macroscopically defined cord insertion site was recorded as velamentous, marginal, or central. The effects of VCI on TTTS and a composite of adverse outcomes, including abortion, death, and neurological morbidities ≤28 days of age, were evaluated with a multiple logistic regression model. Results: A total of 357 monochorionic diamniotic twin pregnancies were analyzed. VCI in both twins was noted in 2.5% of cases and VCI in at least one twin was noted in 22.1% of cases. The incidence of TTTS was 8.4%; the incidence of a composite of adverse outcomes in at least one twin was 9.8%. There was no correlation between VCI and TTTS as well as a composite of adverse outcomes. Discussion: VCI in monochorionic twin pregnancies was not a risk factor for TTTS and severe perinatal morbidities.


Fetal Diagnosis and Therapy | 2016

Incidences of Feto-Fetal Transfusion Syndrome and Perinatal Outcomes in Triplet Gestations with Monochorionic Placentation.

Yuka Sato; Keisuke Ishii; Tae Yokouchi; Takeshi Murakoshi; Kenji Kiyoshi; Soichiro Nakayama; Naoto Yonetani; Nobuaki Mitsuda

Introduction: This study aimed to determine the incidences of feto-fetal transfusion syndrome (FFTS) and perinatal outcomes in triplet gestations with monochorionic placentation. Materials and Methods: In this retrospective cohort study, we evaluated the incidences of FFTS and perinatal outcomes at 28 days of age in cases of triplet gestations with monochorionic placentation who visited our centers before 16 weeks of gestation and delivered over a period of 11 years. Results: In 41 triplet gestations (17 monochorionic triamniotic, 22 dichorionic triamniotic, 1 dichorionic diamniotic, and 1 monochorionic monoamniotic), the incidence of FFTS was 17.1%, and the median gestational age at FFTS diagnosis was 19 weeks. In 123 triplets, the incidences of fetal death and neonatal death at 28 days of age were 8.1 and 0.9%, respectively. None of the surviving infants had grade 3 or 4 intraventricular hemorrhage, while cystic periventricular leukomalacia occurred in 6 of 113 infants (5.3%). The incidence of poor outcomes (death or any major neurological complication at 28 days of age) was 13.8%. Discussion: Seventeen percent of triplet pregnancies with monochorionic placentation developed FFTS, and 14% had a poor outcome. Therefore, triplet gestations with monochorionic placentation should be followed carefully.


Ultrasound in Obstetrics & Gynecology | 2017

Prediction of time to delivery by transperineal ultrasound in second stage of labor

Naoto Yonetani; Ryo Yamamoto; Masaharu Murata; Erika Nakajima; Takako Taguchi; Keisuke Ishii; Nobuaki Mitsuda

To investigate whether the transperineal sonographic (TPS) parameters angle of progression (AoP) and midline angle (MLA) can predict the time remaining in the second stage of labor.


Ultrasound in Obstetrics & Gynecology | 2016

Prediction of delivery time in the second stage of labor using transperineal ultrasound

Naoto Yonetani; Ryo Yamamoto; Masaharu Murata; Erika Nakajima; Takako Taguchi; Keisuke Ishii; Nobuaki Mitsuda

To investigate whether the transperineal sonographic (TPS) parameters angle of progression (AoP) and midline angle (MLA) can predict the time remaining in the second stage of labor.


Fetal Diagnosis and Therapy | 2015

Monochorionic Monozygotic Twin Pregnancy Complicated with Twin-Twin Transfusion Syndrome Presenting with an Obvious Lambda Sign in the First Trimester

Akiko Yamashita; Keisuke Ishii; Nobuhiro Hidaka; Naoto Yonetani; Shusaku Hayashi; Makoto Takeuchi; Nobuaki Mitsuda

In this report, we present a case of twin-twin transfusion syndrome in the presence of the thick dividing wall of each sac in dichorionic twins. The dichorionic diagnosis was based on the presence of the lambda sign at the first-trimester ultrasound evaluation. In addition to fetoscopic and pathological investigation, DNA typing confirmed that the twin set was monochorionic and monozygotic. This case illustrates that although extremely uncommon, the presence of lambda sign does not exclude monochorionic pregnancy.


Journal of Obstetrics and Gynaecology Research | 2018

Effect of prolonged hospitalization for threatened preterm labor on maternal and fetal vitamin D levels

Naoto Yonetani; Takashi Kaji; Atsuko Hichijo; Soichiro Nakayama; Kazuhisa Maeda; Minoru Irahara

We aimed to evaluate the effect of prolonged hospitalization for threatened preterm labor (TPL) on maternal and fetal vitamin D status.


Fetal Diagnosis and Therapy | 2016

Twin-Twin Transfusion Syndrome in Cases with Suspected Close Proximity of Umbilical Cord Insertions.

Yuka Sato; Keisuke Ishii; Naoto Yonetani; Ryo Yamamoto; Nobuaki Mitsuda

We encountered 3 cases of twin-twin transfusion syndrome (TTTS), in which preoperative ultrasonography revealed that the cord insertion sites of the twins were close. Two cases were successfully treated with fetoscopic laser photocoagulation (FLP); however, the third case could not be treated surgically because fetoscopy revealed that the cord insertions formed a V-shaped joint above the placenta and that all chorionic vessels of the placental surface were shared by the twins. No residual anastomoses were detected on placental examination in the 2 cases treated with FLP. Our experiences indicate that the feasibility of FLP could be evaluated using fetoscopy, not just ultrasonography, in cases of TTTS accompanied by proximate umbilical cord insertion.


Fetal Diagnosis and Therapy | 2016

Contents Vol. 40, 2016

Keisuke Ishii; Naoto Yonetani; Nobuaki Mitsuda; Yuka Sato; Ryo Yamamoto; Stefan C. Kane; Sammya Bezerra Maia e Holanda Moura; J. Hyett; Fabrício da Silva Costa; Elissa Willats; Kim-Phoung Nguyen; Olutoyin A. Olutoye; Paula Domínguez-Manzano; Alberto Mendoza; I. Herraiz; D. Escribano; Violeta Román; Juan M. Aguilar; Alberto Galindo; Alvaro Sepúlveda-Martínez; M. Parra-Cordero; Marcelo Rodríguez; José A. Moreno; Rolando Márquez; Ricardo Eltit; Felipe Martínez; K.K. Haratz; G. Malinger; Zvi Leibovitz; Ran Svirsky

R. Achiron, Tel Hashomer N.S. Adzick, Philadelphia, Pa. L. Allan, London A.A. Baschat, Baltimore, Md. K.J. Blakemore, Baltimore, Md. T.-H. Bui, Stockholm F.A. Chervenak, New York, N.Y. T. Chiba, Tokyo R. Chmait, Los Angeles, Calif. F. Crispi, Barcelona J.E. De Lia, Milwaukee, Wisc. J.A. Deprest, Leuven G.C. Di Renzo, Perugia J.W. Dudenhausen, Berlin N.M. Fisk, Brisbane, Qld. A.W. Flake, Philadelphia, Pa. U. Gembruch, Bonn M.R. Harrison, San Francisco, Calif. J.C. Hobbins, Denver, Colo. L.K. Hornberger, Edmonton, Alta. E.R.M. Jauniaux, London M.P. Johnson, Philadelphia, Pa. J.-M. Jouannic, Paris P.M. Kyle, London O. Lapaire, Basel S. Lipitz, Tel Hashomer E. Llurba, Barcelona G. Malinger, Tel Aviv G. Mari, Detroit, Mich. M. Martinez-Ferro, Buenos Aires A. McLennan, Sydney, N.S.W. K.J. Moise, Houston, Tex. F. Molina, Granada K.H. Nicolaides, London L. Otaño, Buenos Aires Z. Papp, Budapest R.A. Quintero, Miami, Fla. G. Ryan, Toronto, Ont. J. Rychik, Philadelphia, Pa. H. Sago, Tokyo W. Sepulveda, Santiago P. Stone, Auckland D.V. Surbek, Bern B.J. Trudinger, Westmead, N.S.W. Y. Ville, Paris J.M.G. van Vugt, Nijmegen Clinical Advances and Basic Research


Journal of Obstetrics and Gynaecology Research | 2015

Prenatally diagnosed monochorionic diamniotic triplet pregnancy.

Naoto Yonetani; Keisuke Ishii; Aki Mabuchi; Jun Sasahara; Shusaku Hayashi; Nobuaki Mitsuda

We present an extremely rare case of monochorionic diamniotic (MD) triplet pregnancy diagnosed via ultrasonography at the end of the first trimester that resulted in delivery of three healthy newborns. Ultrasonography for a 34‐year‐old woman at 12 weeks of gestation showed three fetuses and one placenta with a T‐sign at the initial segment of the dividing membrane. Color Doppler examination revealed umbilical cord entanglement between two fetuses in one sac in addition to another sac containing one fetus. Therefore, this was diagnosed as MD triplet pregnancy. The triplets were delivered by cesarean section at 35 weeks of gestation and were healthy without neurological morbidities at the age of 28 days. Histopathological examination also revealed an MD triplet placenta. The possibility of MD triplet pregnancy should be recognized, although it is rare.


Journal of Obstetrics and Gynaecology Research | 2015

Significance of chorionicity on long‐term outcome of low birthweight infants of <1500g in twin pregnancies

Hiroshi Kawamura; Keisuke Ishii; Naoto Yonetani; Aki Mabuchi; Shusaku Hayashi; Nobuaki Mitsuda

The aim of this study was to evaluate the long‐term outcomes of very low birthweight twins by chorionicity and to identify the perinatal predictors for outcomes in the era of laser surgery for twin–twin transfusion syndrome.

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Takashi Kaji

University of Tokushima

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Ryo Yamamoto

Boston Children's Hospital

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