Research Paper Co-Authored by Dr. Masaaki Ban of Roppongi Ladies Clinic Ikebukuro Published in Journal of Japan Society for Fertilization and Implantation

Dr. Masaaki Ban, Director of Roppongi Ladies Clinic Ikebukuro—a clinic supported by SBC Medical Group Holdings (based in California, USA; CEO: Yoshiyuki Aikawa)—has published a joint research paper as the lead author titled "Uncertainty of Aneuploidy Assessment in Preimplantation Genetic Testing: A Report of Two Cases Where Mosaic Embryos Were Re-identified through PGT-A Re-analysis, Leading to Healthy Births." The paper was featured in Vol. 43 No. 1 (2026) of the "Journal of the Japan Society for Fertilization and Implantation." The research provides insights into interpreting results from PGT-A, a test widely used in fertility treatments, and emphasizes the importance of decision support tailored to each patient.

PGT-A (Preimplantation Genetic Testing for Aneuploidy) is a test that examines the chromosome count of embryos obtained through in vitro fertilization. While it is widely used to improve implantation rates and reduce miscarriage risks, some embryos initially identified as aneuploid contain a mix of normal and abnormal cells, known as "mosaic embryos." Discussions regarding their evaluation and handling are ongoing.

This study reports two cases where embryos initially diagnosed as aneuploid were re-classified as mosaic after re-analysis, eventually resulting in the birth of healthy babies. These findings deepen the understanding of result interpretation and the importance of re-evaluation in PGT-A, potentially contributing to more flexible, patient-centered decision support and improved clinical practices.

Publication Overview

Journal: Journal of the Japan Society for Fertilization and Implantation
Volume/Issue: Vol. 43 No. 1, pp. 65-70, 2026
Title: Uncertainty of Aneuploidy Assessment in Preimplantation Genetic Testing: A Report of Two Cases Where Mosaic Embryos Were Re-identified through PGT-A Re-analysis, Leading to Healthy Births
Authors: Masaaki Ban, Tatsuhito Inohana, Kazuko Takahashi, Maki Kusumi, Osamu Tsutsumi

About Dr. Masaaki Ban
After graduating from the University of Miyazaki School of Medicine, Dr. Ban gained experience in obstetrics and gynecology at the National Center for Global Health and Medicine and Keio University Hospital. He deepened his expertise in advanced reproductive medicine at the Asada Ladies Clinic. He joined Roppongi Ladies Clinic in 2023. Currently serving as the Director of Roppongi Ladies Clinic Ikebukuro, he is also pursuing research on PGT-A at the International University of Health and Welfare Graduate School, contributing to the development of reproductive medicine from both clinical and academic perspectives.