AimThe 2018 International Federation of Gynecology and Obstetrics abnormal uterine bleeding System‐1 defines menstrual flow volume on a 3‐point scale based on subjective assessment. However, the normal flow range has not been established, and it is unclear whether subjective assessment is accurate. We investigated the normal menstrual flow volume range in Japanese women and whether the actual measured menstrual flow volume agreed with the subjective evaluation.MethodsWe included female menstruating volunteers aged 18–49 years in this prospective observational study. Menstrual napkins were weighed before and after use for up to three cycles, and the values were recorded in an online diary.ResultsOverall, 211 participants were recruited. All items were completed by 167 participants, and 497 menstrual cycles were included in the analysis. The median total menstrual flow volume per cycle for 497 cycles was 56.7 g. The 5th–95th percentile values ranged from 15.7 to 166.4 g. The mean value was 77.6 ± 99.6 g, with no significant differences according to age group. In the 25 cycles corresponding to heavy flow, that is, above the 95th percentile of measured flow volume, 92% were underrated as “normal” by subjective evaluation, and only 8% were correctly rated as “heavy.”ConclusionsOur results clarify the actual menstrual flow volume in the Japanese population; this will contribute toward making women aware of the normal range of menstrual flow volume, which may facilitate appropriate preconception care.

中文翻译：

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日本女性卫生巾测得的正常月经量范围及其特性：测得的月经量与主观月经量之间的差异


目的2018 年国际妇产科联合会异常子宫出血系统 1 根据主观评估以 3 分制定义月经量。然而，正常流量范围尚未确定，主观评估是否准确尚不清楚。我们调查了日本女性的正常月经量范围，以及实际测量的月经量是否与主观评价一致。方法我们在这项前瞻性观察研究中纳入了 18-49 岁的女性月经志愿者。月经餐巾在使用前后称重最多三个周期，并将这些值记录在在线日记中。结果总体而言，共招募了 211 名参与者。所有项目均由 167 名参与者完成，分析包括 497 个月经周期。497 个周期每个周期的中位总月经量为 56.7 g。第 5-95 个百分位值范围为 15.7 至 166.4 g。平均值为 77.6 ± 99.6 g，不同年龄组差异无统计学意义。在对应于大流量的 25 个循环中，即高于测量流量的第 95 个百分位数，92% 被主观评估低估为“正常”，只有 8% 被正确评为“重”。结论我们的结果阐明了日本人群的实际月经量;这将有助于让女性了解月经量的正常范围，这可能有助于适当的孕前护理。