Publication
Clinical research paper by YUIRYOU CEO Tomohiro Mitoma published in an international journal
A clinical research paper by Tomohiro Mitoma (first author), CEO of YUIRYOU, has been published in the Journal of Obstetrics and Gynaecology Research — a retrospective observational study on intraoperative transvaginal ultrasonographic evaluation for placenta accreta spectrum in placenta previa.
Tomohiro Mitoma, CEO of YUIRYOU Inc. and first author, has published a clinical research paper in the Journal of Obstetrics and Gynaecology Research. The study is a retrospective observational study on intraoperative transvaginal ultrasonographic evaluation for placenta accreta spectrum (PAS) in placenta previa.
Paper information
- Title: Intraoperative Transvaginal Ultrasonographic Evaluation for Placenta Accreta Spectrum in Placenta Previa: A Retrospective Observational Study
- Journal: Journal of Obstetrics and Gynaecology Research (June 2026 / Vol. 52, Issue 6)
- Published online: June 4, 2026
- Authors: Tomohiro Mitoma (first author), Shujiro Sakata, Ayano Suemori, Kei Hayata, Jota Maki
- DOI: 10.1111/jog.70353
Mitoma participated as first author from YUIRYOU.
Key findings
- During cesarean delivery for placenta previa, the duration of residual color Doppler signal in the cervical hypervascularity zone was measured via transvaginal ultrasound (TVUS)
- The study examined whether this "blood flow duration" could serve as an indicator for identifying placenta accreta spectrum (PAS)
- A single-center retrospective observational study in which surgical video was independently evaluated by two OB-GYNs
Background and purpose
When placenta accreta spectrum (PAS) complicates placenta previa, the risk of massive hemorrhage and hysterectomy during delivery increases. While prenatal imaging has advanced, objective real-time indicators for assessing PAS during surgery have been limited.
This study focused on the duration of low-velocity (≤2.0 cm/s) color Doppler signals persisting in the cervical hypervascularity zone after fetal delivery, evaluating whether it could serve as a supplementary diagnostic tool for PAS.
Main results
Key results reported in the study (all within the study population):
- PAS was diagnosed in 20 cases (38.5%) of the study cohort
- Blood flow duration was significantly longer in PAS cases (mean 20.20 min) than non-PAS cases (mean 5.69 min)
- Using a 7-minute cutoff: sensitivity 100%, specificity 72% (AUC 0.94) — cessation within 7 minutes could potentially rule out PAS
- At ≥14 minutes: 100% positive predictive value for PAS, 96% specificity for predicting hysterectomy
- In multivariate analysis, blood flow duration was an independent predictor of PAS (AUC 0.95)
Clinical significance and future directions
The study demonstrated that blood flow duration in the cervical hypervascularity zone, measured by intraoperative TVUS, may serve as a supplementary indicator when PAS is suspected. Short duration (<7 min) suggests a lower likelihood of PAS; prolonged duration (≥14 min) suggests PAS and the need for more cautious surgical management.
However, this is a single-center retrospective observational study with a limited sample size. These values cannot be generalized directly, and future multi-center prospective validation is needed. Clinical decisions should be made comprehensively by the treating physician based on individual circumstances.
About YUIRYOU
YUIRYOU supports healthcare companies through two physicians who cover both research and communication. This paper demonstrates that our team members are actively involved in clinical research — from study design and evaluation metrics to English-language publication. These capabilities are directly aligned with the clinical research and publication support we provide to healthcare companies. Please contact us if you would like to connect research with business credibility.
References
Frequently asked questions
Is this announcement medical advice?
No. This article is a notification about the publication of an academic paper and does not constitute diagnostic or treatment guidance. The study results described are observational findings within the study population. Individual clinical decisions are made by the treating physician based on comprehensive assessment.
Where can I read the full paper?
The full text is available on the Journal of Obstetrics and Gynaecology Research website. Access it via the reference link at the end of this article or through DOI 10.1111/jog.70353.
How was YUIRYOU involved in this research?
Our CEO, Tomohiro Mitoma, participated as first author. The work from study design through publication is the same domain as the clinical research and publication support YUIRYOU offers to companies.