虽然对于产科医生来说，基本了解骨盆大小和分类仍然很重要，但针对日本女性的骨盆测量数据非常稀缺。据我们所知，过去50年内没有对日本女性进行过大规模的骨盆测量研究。本研究旨在利用三维计算机断层扫描（CT）技术，调查现代日本女性的准确大小，特别是产科连合径（OC）和盆腔入口横径（TD），并获得它们的参考值。这是一项回顾性的单中心观察性研究，招募了在2016至2021年期间接受骨盆CT检查的年龄在20至40岁之间的非孕日本女性。CT检查是为了诊断急性腹痛、寻找癌症转移和随访现有疾病等各种原因而进行的，但没有进行骨盆测量。利用三维工作站对骨盆进行了回顾性测量，产科连合径在严格的侧面视图上进行测量，盆腔入口横径在轴位斜视图上进行测量。从医疗记录中提取了其他临床数据，如年龄、身高和体重，并进行了分析。 共招募了1,263名患者，平均年龄为32.7岁（标准差[SD] 6.2）。平均身高、体重和体重指数分别为158.8厘米（SD 5.8）、54.8公斤（SD 11.7）和21.7千克/平方米（SD 4.4）。平均产科连合径长度为127.0毫米（SD 9.5，95%置信区间[CI]126.5-127.5），盆腔入口横径长度为126.8毫米（SD 7.5，95% CI 126.4-127.2）。两个值均呈正态分布。身高与产科连合径（回归系数= 0.75 [95% CI 0.66-0.84]，P <0.001）和盆腔入口横径（回归系数= 0.63 [95% CI 0.56-0.70]，P <0.001）显著相关。年龄与盆腔入口横径（回归系数= 0.14 [95% CI 0.07-0.20]，P <0.001）和产科连合径（回归系数= -0.10 [95% CI -0.18 to -0.01]，P = 0.026）之间存在弱但显著的正相关。 针对1,263名处于育龄的非孕日本女性进行的三维CT骨盆测量显示，产科连合径和盆腔入口横径的平均值分别为127.0毫米和126.8毫米，比1972年进行的调查中的均值分别大11.8毫米和4.3毫米。我们的数据将作为日本人群标准骨盆测量值用于临床实践中。

While a basic understanding of pelvic size and typology is still important for obstetricians, pelvic measurement data for Japanese women are very scarce. To our best knowledge, no large-scale pelvimetry studies of Japanese women have been made for the past 50 years. This study aimed to investigate the accurate size, particularly the obstetric conjugate (OC) and transverse diameter of the pelvic inlet (TD), of modern Japanese women, using three-dimensional (3D) computed tomography (CT), and to obtain their reference values.This retrospective, single-center observational study enrolled Japanese non-pregnant women aged between 20 and 40 years, who underwent pelvic CT examination from 2016 to 2021. CT was performed for various reasons, including acute abdomen, search for cancer metastases, and follow-up of existing disease. However, no cases were taken for pelvic measurements. Pelvimetry was performed retrospectively using a 3D workstation. The OC was measured on a strict lateral view and the TD was measured on an axial-oblique view. Other clinical data, such as age, height, and weight, were also extracted from the medical charts and analyzed.A total of 1,263 patients were enrolled, with the mean age of 32.7 years (standard deviation [SD] 6.2). The mean height, weight, and body mass index were 158.8 cm (SD 5.8), 54.8 kg (SD 11.7), and 21.7 kg/m2 (SD 4.4), respectively. The mean OC length was 127.0 mm (SD 9.5, 95% confidence interval [CI] 126.5-127.5), while the mean TD length was 126.8 mm (SD 7.5, 95% CI 126.4-127.2). Both values were normally distributed. Height was significantly associated with OC (regression coefficient = 0.75 [95% CI 0.66-0.84], p < .001) and TD (regression coefficient = 0.63 [95% CI 0.56-0.70], p < .001). Age showed a weak but statistically significant positive association with TD (regression coefficient = 0.14 [95% CI 0.07-0.20], p < .001) and OC (regression coefficient = -0.10 [95% CI -0.18 to -0.01], p = .026).The 3D CT pelvimetry in 1,263 non-pregnant Japanese women of childbearing age revealed the mean OC and TD of 127.0 mm, and 126.8 mm, which were 11.8 mm and 4.3 mm larger, respectively, than those in the survey in 1972. Our data will be referred to in clinical practice as the standard pelvic measurement values for the Japanese population.