Identification and prediction of the fertile window using NaturalCycles

Abstract

Objectives The aim of the study was to evaluate the ability of a novel web and mobile application to identify a woman's ovulation day and fertile window, in order to use it as a method of natural birth control.

Methods A retrospective study was performed on 1501 cycles of 317 women aged 18 to 39 years. Women entered their basal body temperatures, ovulation test results and date of menstruation into the application.

Results The mean delay from the first positive ovulation test to the temperature-based estimation of the ovulation day was 1.9 days; the length of the luteal phase varied on average by 1.25 days per user. Only 0.05% of non-fertile days were falsely attributed and found within the fertile window.

Conclusions The method is effective at identifying a user's ovulation day and fertile window and can therefore be used as a natural method of birth control.

Chinese Abstract

摘要

目的：本研究的目的为评估一个新的网页及移动设备应用鉴别女性排卵日和生育窗的能力，以便将其用于指导自然避孕。

方法：年龄在18至37岁的317名妇女的1501个月经周期被纳入了回顾性研究。受试者将基础体温、排卵测试结果和经期输入至此应用。

结果：首次排卵阳性日至基础体温预计排卵日的平均延迟时间为1.9天；平均每个受试者的黄体期时间变化大约为1.25天。只有0.05%的非生育期被错误地归至生育窗。

结论：此方法可有效识别使用者排卵日及生育窗，因此可应用于自然避孕。

关键词

自然生育控制，生育窗，自然避孕，生育力认知，基础体温，排卵监测

Keywords:

• Natural birth control
• Fertile window
• Natural family planning
• Fertility awareness
• Basal body temperature
• Fertility monitor

ACKNOWLEDGEMENTS

We thank Göran Berglund and Dolf van Loon for fruitful and challenging discussions. We also thank Eliza Hazlerigg for carefully reading through and editing the manuscript.

Declaration of interest: ALH declares no conflict of interest. EBS and RS are the scientists behind the application and the company.