Long working hours among hospital-employed obstetricians and gynecologists and associated factors: a comparative study based on a nationwide survey

Abstract

Objectives: To elucidate the status of reduction in working hours following physician work-style reforms and factors associated with long working hours. Methods: A nationwide questionnaire survey was conducted among obstetricians and gynecologists (OB/GYNs) working in hospitals. The survey elucidated actual working conditions, including working hours and number of out-of-hour (OOH) shifts. To identify factors associated with long working hours, a multivariate logistic regression analysis was performed, with ≥60 or ≥80 working hours per week as dependent variables and OB/GYNs attributes (sex, age, job position, hospital type by ownership, total number of hospital beds, and regional characteristics) as independent variables. Results: Questionnaires were sent to 1,170 hospitals. Valid responses were obtained from 1164 OB/GYNs at 423 hospitals (response rate: 36%): 26.0% worked ≥60 hours per week, a reduction from 58.1% in 2019 (equivalent to over 960 hours of overtime annually), 5.4% worked ≥80 hours per week, a reduction from 41.2% in 2019 (equivalent to over 1,920 hours of overtime annually); and 46.9% worked OOH shifts ≥5 times per month. Factors significantly associated with long working hours per week included male sex, resident position, teaching duty, and number of OOH shifts. Conclusions: Although the working hours of OB/GYNs have decreased because of physician work-style reforms initiated in 2019, long working hours persist. To ensure health of OB/GYNs and patient safety, it is necessary to actively promote physician work-style reforms and advance measures aimed at the centralization of medical resources and addressing their maldistribution.

Introduction

Working hours in Japan are long by international standards¹⁾. Compared with other professions, physicians work particularly long hours, with 42% of full-time physicians working >200 days per year, exceeding 60 hours per week, which is the highest percentage compared with the average 14% across all professions²⁾. Among physicians, hospital-based obstetricians and gynecologists (OB/GYNs) have the longest working hours, with 20.5% working >1,920 hours of overtime annually (averaging ≥80 hours per week)³⁾. This could be attributed to specific demands or capacity issues that increase the workload.

Both domestic and international evidence are available regarding the adverse health effects of long working hours. A systematic review by Bannai et al. found that long working hours were associated with depressive state, anxiety, poor sleep conditions, and coronary heart disease⁴⁾. Suicide due to depression and deaths from ischemic heart disease and cerebrovascular disease caused by excessive workload are termed “karoshi (death from overwork),” which has become a public health issue, particularly in East Asian countries, including China^5,6).

In 2019, the authors conducted a survey to shed light on the state of overwork among OB/GYNs in Japanese hospitals, highlighting that long working hours may lead to depression and suicidal ideation⁷⁾. During the survey, most OB/GYNs (37.5%) reported working 60–80 hours per week, 27.1% worked ≥100 hours, and 19.5% worked 80–100 hours per week.

However, no research has been conducted on the factors associated with the working hours of OB/GYNs. The Ministry of Health, Labour and Welfare (MHLW) indicates that a high proportion of young physicians in their 20s and 30s work >1,920 hours of overtime annually³⁾. However, the relationships between physician characteristics (such as sex and job position), hospital characteristics, regional characteristics, and long working hours remain unclear.

Since 2019, the MHLW has been leading work-style reforms for physicians. Specific efforts aimed at reducing working hours include task shifting, thorough management of working hours, and utilization of existing occupational health systems. However, it is unclear whether these measures reduced the working hours of OB/GYNs⁸⁾. Therefore, this study analyzed whether the working hours of OB/GYNs decreased as a result of the work-style reforms for physicians implemented in 2019. Furthermore, we explored factors contributing to prolonged working hours at three levels: individual, hospital, and regional. Based on these findings, we considered measures aimed at addressing the issue of long working hours among OB/GYNs. The comparison of prolonged working hours with 2019 data is a secondary aim of this study.

Methods

The methodology used for this study was the same as that of the survey conducted in 2019⁷⁾.

Participants

In November 2023, survey request forms were sent to the heads and OB/GYNs of the obstetrics and gynecology departments of 1,170 hospitals nationwide that are listed in the Hospital Bed Function Reporting System⁹⁾. A web-based questionnaire was administered. The duration of data collection was 2 weeks. Pilot tests were not conducted.

Measurement: survey items

The survey collected information on characteristics of responding OB/GYNs (sex, age, job position, teaching duties, number of children, weekly working hours, number of out-of-hour [OOH] shifts, hospital type by ownership, total number of beds, and regional characteristics; Table 1). Age was classified into five categories: <30, 30–39, 40–49, 50–59, and ≥60 years. Job positions were classified into four categories: department head, staff physician, senior resident, and others. Weekly working hours were classified into five categories: <40, 40–59, 60–79, 80–99, and ≥100 hours. The hospitals in which respondents worked were classified into four categories: public, national, private, and private (excluding private universities). The total number of beds was classified into five categories: <200, 200 to <400, 400 to <600, 600 to <800, and ≥800. In Japan, 344 secondary medical areas were classified into three categories based on a combination of population size and density in 2023¹⁰⁾.

Table 1. Characteristics of participants

	Total		Over 60 hours per week		Over 80 hours per week
Total participants, n	1,164		303		63
Percentage of participants	100.0%		26.0%		5.4%
Sex, n, %
Female	580	49.8%	112	37.0%	17	27.0%
Male	584	50.2%	191	63.0%	46	73.0%
Age, years, n %
<30	130	11.2%	46	15.2%	9	14.3%
30–39	374	32.1%	104	34.3%	25	39.7%
40–49	318	27.3%	81	26.7%	16	25.4%
50–59	187	16.1%	41	13.5%	8	12.7%
≥60	155	13.3%	31	10.2%	5	7.9%
Job position
Department head	325	27.9%	73	24.1%	11	17.5%
Staff physician	582	50.0%	141	46.5%	30	47.6%
Senior resident	223	19.2%	83	27.4%	21	33.3%
Other	34	2.9%	6	2.0%	1	1.6%
Presence of teaching duties
Yes	585	50.3%	170	56.1%	42	66.7%
No	579	49.7%	133	43.9%	21	33.3%
Number of children
None	409	35.1%	125	41.3%	24	38.1%
1	189	16.2%	47	15.5%	9	14.3%
2	363	31.2%	80	26.4%	21	33.3%
3	168	14.4%	44	14.5%	7	11.1%
≥4	35	3.0%	7	2.3%	2	3.2%
Working hours per week, n, %
<40	148	12.7%	0	0.0%	0	0.0%
40–59	710	61.0%	0	0.0%	0	0.0%
60–79	240	20.6%	240	79.2%	0	0.0%
80–99	46	4.0%	46	15.2%	46	73.0%
≥100	17	1.5%	17	5.6%	17	27.0%
Number of out-of-hour shifts per month
0	217	18.6%	18	5.9%	2	3.2%
1–4	401	34.5%	90	29.7%	14	22.2%
5–8	398	34.2%	138	45.5%	25	39.7%
≥9	148	12.7%	57	18.8%	22	34.9%
Entity of employer
Public	668	57.4%	170	56.1%	29	46.0%
National university	121	10.4%	39	12.9%	11	17.5%
Private university	69	5.9%	29	9.6%	8	12.7%
Private	306	26.3%	65	21.5%	15	23.8%
Employer’s total bed number
<200	90	7.7%	17	5.6%	3	4.8%
≥200 to <400	320	27.5%	63	20.8%	12	19.0%
≥400 to <600	399	34.3%	104	34.3%	20	31.7%
≥600 to <800	203	17.4%	60	19.8%	12	19.0%
≥800	152	13.1%	59	19.5%	16	25.4%
Workplace area, n, %
Urban	558	47.9%	139	45.9%	30	47.6%
Intermediate	489	42.0%	137	45.2%	28	44.4%
Rural	117	10.1%	27	8.9%	5	7.9%

Statistical analysis

To identify factors associated with long working hours, we conducted multivariate logistic regression analysis^11,12). The dependent variables were whether weekly working hours exceeded the so-called “karoshi threshold” of 60 and 80 hours per week. The independent variables were characteristics of responding OB/GYNs (sex, age, job position, teaching duties, number of children, number of OOH shifts per month, hospital type by ownership, total number of hospital beds, and regional characteristics). Statistical analyses were considered significant at p-values <0.05. STATA version 17.0 (Stata Corp, College Station, TX, USA) was used for all statistical analyses.

Ethical considerations

This study was approved by the Human Research Ethics Committee of Tokyo Healthcare University (approval number: Edu023-03B). The purpose of this study and measures to ensure secure data management were stated on the first page of the questionnaire. We also explained to the potential participants that their involvement in the study was voluntary. The results were analyzed independently of personal information to allow for anonymity and confidentiality of personal information. Written informed consent was obtained from the study participants.

Results

The questionnaire was sent to 1,170 hospitals nationwide. Valid responses were obtained from 423 hospitals (response rate: 36%) and involved a total of 1,164 OB/GYNs. The 1,164 responding OB/GYNs represented 16.3% of the 7,127 hospital–based OB/GYNs included in the 2022 Survey of Physicians, Dentists, and Pharmacists¹³⁾ conducted by the MHLW.

The characteristics of OB/GYNs are presented in Table 1; 49.8% of the respondents were women. Most OB/GYNs were aged 30–39 years, accounting for 32.1% of all OB/GYNs. A total of 57.4% worked in public hospitals and 47.9% in large cities. Regarding weekly working hours, 61.6% worked 40–59 hours; 20.6%, 60–79 hours; 4.0%, 80–99 hours; and 1.5%, ≥100 hours. Compared with the 2019 survey, 26.0% worked ≥60 hours per week, a reduction from the 58.1% in 2019 and 5.4% worked ≥80 hours per week, a reduction from 41.2% observed in 2019⁷⁾.

Multivariate logistic regression analysis is presented in Table 2. With working ≥60 hours per week as the dependent variable, significant associations were found with male sex (reference: female sex; odds ratio [OR] 2.10; 95% confidence interval [CI], 1.53–2.90, p<0.01), senior resident position (reference: department head position; OR 2.13; 95% CI, 1.12–4.06, p=0.02), teaching duty (reference: no teaching duty; OR 1.46; 95% CI, 1.04–2.05, p=0.03), working 1–4 OOH shifts per month (reference: 0 OOH shifts; OR 2.35; 95% CI, 1.41–3.93, p<0.01), working 5–8 OOH shifts (reference: 0 OOH shifts; OR 3.89; 95% CI, 2.34–6.48, p<0.01), and working ≥9 OOH shifts per month (reference: 0 OOH shifts; OR 5.95; 95% CI, 3.20–11.10, p<0.01).

Table 2 . Logistic regression analysis of factors associated with longer working hours

Over 60 hours per week				Over 80 hours per week
	Odds ratio	95% CI	P‑value		Odds ratio	95% CI	p‑value
Sex				Sex
Female	Reference			Female	Reference
Male	2.10	1.53–2.90	<0.01	Male	2.42	1.26–4.62	0.01
Age				Age
Under 30	Reference			Under 30	Reference
30–39	1.13	0.64–2.00	0.68	30–39	1.68	0.62–4.53	0.30
40–49	1.16	0.59–2.26	0.67	40–49	1.29	0.40–4.21	0.67
50–59	0.93	0.43–1.99	0.85	50–59	1.42	0.36–5.64	0.62
≥60	1.06	0.46–2.44	0.89	≥60	1.60	0.32–7.96	0.56
Job position				Job position
Department head	Reference			Department head	Reference
Staff physician	1.03	0.66–1.62	0.89	Staff physician	1.61	0.61–4.20	0.33
Senior resident	2.13	1.12–4.06	0.02	Senior resident	7.05	2.09–23.72	<0.01
Other	1.18	0.41–3.40	0.76	Other	1.76	0.18–16.78	0.62
Presence of teaching duties				Presence of teaching duties
No	Reference			No	Reference
Yes	1.46	1.04–2.05	0.03	Yes	2.66	1.32–5.36	0.01
Number of children				Number of children
None	Reference			None	Reference
1	0.82	0.52–1.29	0.39	1	0.91	0.36–2.29	0.85
2	0.71	0.47–1.08	0.11	2	1.39	0.63–3.09	0.42
3	1.01	0.61–1.69	0.95	3	1.10	0.37–3.24	0.87
≥4	0.67	0.26–1.72	0.40	≥4	1.57	0.29–8.45	0.60
Number of out-of-hour shifts per month				Number of out-of-hour shifts per month
0	Reference			0	Reference
1–4	2.35	1.41–3.93	<0.01	1–4	3.43	0.75–15.66	0.11
5–8	3.89	2.34–6.48	<0.01	5–8	5.02	1.12–22.55	0.04
≥9	5.95	3.20–11.10	<0.01	≥9	17.03	3.67–79.08	<0.01
Entity of employer				Entity of employer
Public	Reference			Public	Reference
National university	0.70	0.40–1.23	0.22	National university	0.97	0.34–2.71	0.96
Private university	0.94	0.44–2.03	0.87	Private university	0.83	0.22–3.17	0.78
Private	0.76	0.52–1.13	0.18	Private	0.93	0.43–1.99	0.84
Employer’s total bed number				Employer’s total bed number
<200	Reference			<200	Reference
≥200 to <400	0.75	0.38–1.46	0.40	≥200 to <400	0.78	0.19–3.22	0.73
≥400 to <600	0.95	0.49–1.86	0.88	≥400 to <600	0.98	0.24–4.02	0.98
≥600 to <800	1.16	0.55–2.45	0.69	≥600 to <800	1.06	0.22–5.09	0.95
≥800	1.66	0.73–3.79	0.23	≥800	1.62	0.32–8.29	0.56
Workplace area				Workplace area
Urban	Reference			Urban	Reference
Intermediate	1.09	0.80–1.49	0.57	Intermediate	1.00	0.56–1.81	0.99
Rural	0.95	0.55–1.62	0.84	Rural	0.86	0.29–2.56	0.79
* p<0.05				* P<0.05
CI, confidence interval.

With working ≥80 hours per week as the dependent variable, significant associations were found with male sex (reference: female sex; OR 2.42; 95% CI, 1.26–4.62, p=0.01), senior resident position (reference: department head position; OR 7.05; 95% CI, 2.09–23.72, p<0.01), teaching duty (reference: no teaching duty; OR 2.66; 95% CI, 1.32–5.36, p=0.01), working 5–8 OOH shifts (reference: 0 OOH shifts; OR 5.02; 95% CI, 1.12–22.55, p=0.04), and working ≥9 OOH shifts (reference: 0 OOH shifts; OR 17.03; 95% CI, 3.67–79.08, p<0.01).

Discussion

This survey found that 26.0% of OB/GYNs worked >60 hours and 5.4% worked >80 hours per week. Compared with the 2019 survey conducted by the authors, 84.1% worked >60 hours and 46.6% worked >80 hours per week; notably, the working hours of OB/GYNs have markedly decreased. However, some OB/GYNs continue to work long hours⁷⁾. Possible factors for reducing working hours include improved efficiency, task shifting, or changes in reporting accuracy.

Working long hours for several months is referred to as the “karoshi level” owing to its strong association with the development of mental health problems and cardiovascular disease caused by psychological stress. This level is used as a criterion for determining work-related accidents^11,12). This study suggests that 26.0% of the respondents work in environments exceeding the “karoshi threshold.” Reducing work hours may contribute to improving the mental health of doctors^7,14).

The MHLW implemented work-style reforms for physicians in April 2024, setting the annual overtime limit for physicians at 960 hours as a general rule, with the special exception of 1,860 hours. Various efforts are underway to achieve this goal⁷⁾. The special exception of 1,860 hours per year translates into an average weekly hospital stay of ≥80 hours. This study suggests that 5.4% of respondents work above this level. Because such long working hours became illegal in April 2024, urgent measures are needed to reduce them.

The extent to which the working hours of OB/GYNs have been reduced as a result of recent Japanese work-style reforms for physicians is unknown. Ishimaru et al. reported physician work schedules from 2009 to 2021 and highlighted the number of off-duty days for employed physicians has been steadily increasing¹⁵⁾. Okawara et al. highlighted differences in the impact of overtime at main workplaces versus side jobs⁶⁾. By looking at details about off-duty days and side jobs in this way, it is possible to analyze the working environment of OB/GYNs in more detail.

Significant associations were found between working ≥60 or ≥80 hours per week and the following factors: male sex, senior resident position, teaching duty, and number of OOH shifts. Thus, hospitals must act to reduce the working hours of OB/GYNs with these characteristics. In contrast, no significant associations were found between age, number of children, type of hospital (public or private), total number of beds, or regional characteristics.

Regarding association with sex, previous studies in the United States have shown that male physicians earn more and work longer hours than female physicians¹⁶⁾. The present study also found a strong association between male sex and longer working hours. As shown in our previous study on pediatricians, male physicians tended to work longer hours¹⁷⁾. However, no significant relationship was found with the number of children, which may have been influenced by women’s tendency to shoulder more childcare responsibilities¹⁸⁾. Given the extremely low level of gender equality in Japan, policy support is needed¹⁹⁾.

Among senior residents, there was a significant trend towards longer working hours. Globally, long working hours are a challenge for residents because they must acquire knowledge and skills for specialty certification²⁰⁾. Various evidence-based studies have been conducted in the United States, where residents’ working hours are regulated by the Accreditation Council for Graduate Medical Education (ACGME). For instance, studies comparing intervention groups of surgery and internal medicine residents without restrictions on continuous work hours or rest intervals with control groups with ACGME-imposed restrictions reported no significant differences in patient outcomes or resident satisfaction^21,22). In Japan, restrictions on continuous working hours and mandatory rest intervals for residents were introduced in April 2024, with anticipated positive effects^3,8).

No significant association was observed of working hours with age. While the MHLW data and a previous study on pediatricians showed an association for those under 30 years, the recent increase in individuals who became physicians after transitioning from other careers suggests that job position has a stronger association with working hours than age^3,16).

The significant association between teaching duties and working hours likely reflects the substantial burden placed on OB/GYNs when teaching duties are added to their clinical work. Prior studies have highlighted that in Japan, university hospital physicians are expected to fulfill clinical, research, and educational functions, and that overwork has become the norm^6,23,24,25). Some hospitals are known for their low remuneration, forcing physicians to take up part-time jobs to meet ends. Therefore, as part of the promotion of the work-style reforms for physicians, further support measures should be considered, such as increasing remuneration and the number of university hospital physicians.

The significant relationship between the number of OOH shifts and working hours is somewhat self-evident: more OOH shifts correlate with longer hours. However, no significant associations were found with factors such as hospital type, ownership, total bed count, or regional characteristics. Using indicators more directly related to physician workload, such as the number of physicians per hospital or population or the number of deliveries and surgical procedures, might have yielded more useful insights.

This study has some limitations. First, owing to the voluntary nature of survey participation, there may have been a selection bias. Despite this limitation, we obtained valid responses from 423 hospitals (36% response rate) and 1,164 individuals (16.3% of the 7,127 OB/GYNs working in hospitals). We believe that this sample size is sufficient to claim a degree of representativeness in terms of both the response rate and number of respondents. Second, as the questionnaire was self-administered, there is a possibility of various information biases. For instance, the reported weekly working hours may not be entirely accurate because they were not based on a detailed time study conducted by a third party. To increase the response rate, we did not provide detailed definitions of the technical terms used in the questionnaires. Third, the statistical associations identified between long working hours and other factors do not necessarily imply causal relationships. However, there may have been unmeasured confounding factors. For example, it remains unclear whether long working hours are the result of personal choices or management decisions. Fourth, since the study relied on self-reported working hours, we cannot elaborate on the differences between self-reported hours, actual clinical work hours, and on-site time. Although the comparison between 2019 and 2023 remains valid due to consistent methodology, changes in management or perceptions of working hours by physicians during this period should also be considered a limitation. Taking into account these limitations will provide a more comprehensive understanding of the reasons behind the long working hours of OB/GYNs, which may be useful for formulating policies to improve their work environments.

Conclusion

Although the working hours of OB/GYNs have decreased as a result of the work-style reforms for physicans initiated in 2019, long working hours persist. To ensure OB/GYN health and patient safety, it is necessary to actively promote physician work-style reforms and advance measures aimed at the centralization of medical resources and addressing their maldistribution.

Acknowledgements

None.

Author contributions

M.I., R.S. and M.O. conceived the study idea; M.I. and Y.S. collected the data; M.I. analyzed the data; and M.I wrote and reviewed the final draft of the manuscript.

Data availability

The datasets used and analyzed during the current study are available from the corresponding author on reasonable request. The data are not publicly available due to ethical restrictions.

Study funding

This study was supported by the Ministry of Education, Culture, Sports, Science and Technology Grant-in-Aid for Scientific Research (22K10436 Empirical Research on Progress and Issues of Work Style Reform to Address the Harsh Working Environments of Obstetricians and Gynecologists Across Japan).

Conflicts of interest

The authors declare that they have no competing interests.

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