Abstract
Introduction The Ministry of Health, Labour, and Welfare of Japan (MHLW) introduced a regulation on physician overtime work in 2024, limiting overtime hours to a maximum of 960 annually. This regulation has raised concerns that the quality of medical care may decline. On the other hand, the shifting demographics of Japan, characterized by an aging population and declining birth rates, suggest a potential decrease in demand for obstetrics and gynecology (OBGYN) services in the future. In Japan, there is no feasible study regarding how many OBGYN doctors are currently lacking and how many of them will be necessary. Herein, we conduct simulations using Japanese insurance claims data to estimate the required number of OBGYN doctors. Methods This is a simulation study. We project future demand based on the current demand, working hours, and demographic changes. Using health insurance claims data, we estimate how many OBGYN doctors will be necessary in the future within the overtime work limit. Results The required number of doctors shows a declining trend that mirrors the declining population. Presently, there is a shortage of 1,500 doctors to comply with the 960-hour limit, and it is anticipated to be until 2040 or later before all doctors adhere to this limit. Several sensitivity analyses consistently support this trend. Conclusions Despite the existing shortage of obstetricians and gynecologists, future demands are expected to decrease. Inter-hospital and regional communication should be promoted for systemic innovations.