Institute for Women's Health, University College London, London, UK.
Statistics and Data Management, SPD Development Company Ltd, Bedford, UK.
Womens Health (Lond). 2021 Jan-Dec;17:17455065211049905. doi: 10.1177/17455065211049905.
Period tracking applications (apps) allow women to track their menstrual cycles and receive a prediction for their period dates. The majority of apps also provide predictions of ovulation day and the fertile window. Research indicates apps are basing predictions on assuming women undergo a textbook 28-day cycle with ovulation occurring on day 14 and a fertile window between days 10 and 16.
To determine how the information period tracker apps give women on their period dates, ovulation day and fertile window compares to expected results from big data.
Five women's profiles for 6 menstrual cycles were created and entered into 10 apps. Cycle length and ovulation day for the sixth cycle were Woman 1-Constant 28 day cycle length, ovulation day 16; Woman 2-Average 23 day cycle length, ovulation day 13; Woman 3-Average 28 day cycle length, ovulation day 17; Woman 4-Average 33 day cycle length, ovulation day 20; and Woman 5-Irregular, average 31 day cycle length, ovulation day 14.
The 10 period tracker apps examined gave conflicting information on period dates, ovulation day and the fertile window. For cycle length, the apps all predicted woman 1's cycles correctly but for women 2-5, the apps predicted 0 to 8 days shorter or longer than expected. For day of ovulation, for women 1-4, of the 36 predictions, 3 (8%) were exactly correct, 9 predicted 1 day too early (25%) and 67% of predictions were 2-9 days early. For woman 5, most of the apps predicted a later day of ovulation.
Period tracker apps should ensure they only give women accurate information, especially for the day of ovulation and the fertile window which can only be predicted if using a marker of ovulation, such as basal body temperature, ovulation sticks or cervical mucus.
经期跟踪应用程序（apps）允许女性跟踪她们的月经周期，并获得经期日期的预测。大多数应用程序还提供排卵日和易孕期的预测。研究表明，这些应用程序的预测是基于假设女性的月经周期为教科书上的 28 天，排卵发生在第 14 天，易孕期在第 10 天至第 16 天之间。
确定经期跟踪应用程序向女性提供的经期日期、排卵日和易孕期信息与大数据的预期结果相比如何。
创建了 5 名女性的 6 个月经周期的个人资料，并将其输入到 10 个应用程序中。第六个周期的周期长度和排卵日为：女性 1-固定 28 天周期长度，排卵日 16；女性 2-平均 23 天周期长度，排卵日 13；女性 3-平均 28 天周期长度，排卵日 17；女性 4-平均 33 天周期长度，排卵日 20；女性 5-不规则，平均 31 天周期长度，排卵日 14。
检查的 10 个经期跟踪应用程序在经期日期、排卵日和易孕期方面提供了相互矛盾的信息。对于周期长度，所有应用程序都正确预测了女性 1 的周期，但对于女性 2-5，应用程序预测的周期长度比预期短 0 至 8 天。对于排卵日，对于女性 1-4，36 个预测中，有 3 个（8%）完全正确，9 个预测提前了 1 天（25%），67%的预测提前了 2-9 天。对于女性 5，大多数应用程序预测排卵日较晚。
经期跟踪应用程序应确保只向女性提供准确的信息，特别是对于排卵日和易孕期，只有使用排卵的标志物，如基础体温、排卵试纸或宫颈粘液，才能进行预测。
