Dr. Hiroki Nakabayashi

About

Dr. Hiroki Nakabayashi is an adjunct physician at Kato Ladies Clinic (KLC) in Shinjuku, Tokyo, who joined the clinic’s natural-cycle and mild-stimulation IVF team in 2023. He is a product of two very different Japanese fertility settings: the university hospital system and stand-alone ART clinics.

He graduated from Showa University School of Medicine in 2015, completed his initial clinical residency at Naha City Hospital in Okinawa, then entered the Department of Obstetrics and Gynecology at Showa University. Across Showa University Hospital, Showa University Fujigaoka Hospital, Keiai Hospital and the Obihiro ART Clinic in Hokkaido, Showa University Northern Yokohama Hospital, Showa University Koto Toyosu Hospital and Showa University Hospital, he accumulated more than a decade of hands-on reproductive and obstetric practice before moving to KLC.

That trajectory gives him a complete view of the infertility patient pathway, from standardized university-hospital gynecological care to the high-volume, outcome-driven environment of a dedicated ART clinic. Consultations with Dr. Nakabayashi are conducted in Japanese.

Clinical Expertise

• In Vitro Fertilization (IVF): full management of natural-cycle and mild-stimulation protocols, with individualized stimulation planning based on ovarian reserve
• Intracytoplasmic Sperm Injection (ICSI): direct sperm injection under the microscope for male-factor infertility and prior fertilization failure
• Female infertility care: evaluation and treatment of ovulation disorders, endometriosis and tubal factors
• Cycle-aligned continuity of care: within KLC’s 365-day clinic calendar, treatment stays synchronized with each patient’s natural cycle to reduce physical and scheduling burden

Why Choose Dr. Hiroki Nakabayashi

The Showa University obstetrics and gynecology department is one of the Kanto region’s established academic training grounds, and Dr. Nakabayashi built his residency and consultant practice entirely within that system, giving him disciplined, guideline-based clinical pathways.

His years at Keiai Hospital and the Obihiro ART Clinic in rural Hokkaido exposed him to referred infertility patients from wide catchment areas, including many cases that had stalled elsewhere. He is therefore experienced in managing the full arc of treatment, from first evaluation to repeated transfer attempts.

He holds the Board-Certified Specialist qualification in obstetrics and gynecology from the Japan Society of Obstetrics and Gynecology, meaning his ART practice follows the society’s standardized ethics and safety requirements.

Professional Affiliations

Board-Certified Specialist in Obstetrics and Gynecology, Japan Society of Obstetrics and Gynecology (JSOG). Credentials are verifiable on the Kato Ladies Clinic physician team page.

Suitable For

• Patients pursuing IVF or ICSI treatment: he provides end-to-end cycle care within KLC’s mild-stimulation program, from ovulation induction monitoring through retrieval and transfer.
• Women seeking infertility evaluation: structured workup and treatment of female-factor causes such as ovulatory dysfunction and endometriosis.
• Patients who prefer an experienced attending physician: dual training in a university hospital network and a specialist ART clinic suits patients looking for a steady, protocol-driven treatment path; note that consultations are in Japanese only.