Short- and long-term effect of contraceptive methods on fecundity

Abstract

Objective: The aim of the study was to compare the effect of previously used contraceptive methods on women’s short- and long-term fecundity. Use of hormonal contraception (HC) was compared with the use of a contraceptive mobile application (app).

Methods: This real-life prospective observational study comprised 2874 women who were attempting to become pregnant using the Natural Cycles mobile app to monitor their fertility. The women registered to use the app between August 2014 and June 2016 with the intention of planning a pregnancy and had previously either used the same app to prevent pregnancy or had recently discontinued HC use. We calculated the average time to pregnancy (TTP) for all women who became pregnant during the study and performed Kaplan–Meier life-table analysis to examine the cumulative probabilities of pregnancy for all women in the study.

Results: The average TTP was 2.3 (95% confidence interval [CI] 2.1, 2.4) and 3.7 (95% CI 3.4, 3.9) cycles for women who had previously used Natural Cycles and HC, respectively. The time to reach 30% pregnancy probability for women previously on HC was 1.6 (95% CI 1.5, 1.8) times longer than for women previously using Natural Cycles. There was no significant difference in the 13 cycle cumulated pregnancy probability between the two groups.

Conclusion: The results show that fertility awareness-based methods of contraception increase short-term pregnancy rates relative to HC, but have no effect on long-term pregnancy rates.

摘要

目的：本研究的目的是比较既往使用的避孕方法对女性短期和长期生育力的影响。使用激素避孕与（HC）使用移动避孕应用程序（app）进行比较。

方法：这项现实生活中的前瞻性观察研究包括2874名尝试怀孕的女性, 他们使用自然周期移动应用程序来监测他们的生育能力。这些女性在2014年8月至2016年6月期间注册使用该app的目的是计划怀孕, 并且之前使用过相同的app预防怀孕或最近停止使用HC。我们计算了研究期间所有怀孕女性的平均怀孕时间（TTP）, 并进行Kaplan-Meier 生命表分析, 以检查研究中所有女性怀孕的累积概率。

结果：既往使用自然周期和 HC 的女性平均 TTP 分别为 2.3（95% 可信区间 [CI] 2.1, 2.4）和 3.7 (95%CI 3.4, 3.9) 个周期。既往使用 HC 的女性达到 30% 妊娠概率的时间是既往使用自然周期女性的 1.6 倍 (95%CI 1.5, 1.8)。两组 13 周期累计妊娠概率差异无统计学意义。

结论：结果表明, 与 HC 相比, 基于生育意识的避孕方法可增加短期妊娠率, 但对长期妊娠率无影响。

Keywords:

• Conception rate
• contraceptive
• mobile application
• subfertility
• time to pregnancy

Author contributions

EBS and OL designed the study, performed data acquisition and analysis, contributed to the interpretation of the data and drafted and revised the manuscript. HKK, JH, JT, KGD and RS contributed to the design of the study, interpretation of the data and critical revision of the manuscript. SPR contributed to drafting the manuscript text, preparation of figures and was responsible for revising the manuscript for submission. JT approved the first draft of the manuscript. Sadly, he was unable to approve the resubmission due to his passing in December of 2018. All authors gave their final approval of this version to be published.

Acknowledgements

We sincerely thank all the women who participated in the study. Furthermore, we would like to thank J. Sellberg for help with the methodology and O. Scheibelreiter for proofreading the manuscript.

Disclosure statement

EBS and RS are the scientists behind the Natural Cycles app and the founders of the company with stock ownership. OL and SPR is employed by NaturalCycles Nordic AB. KGD and HKK serve on the medical advisory board of NaturalCycles and have received honoraria for participating in advisory boards and/or giving presentations on matters related to contraception and fertility regulation for MSD/Merck, Bayer AG, Gedeon Richter, Exeltis, Actavis, Ferring (KGD), Exelgyn (KGD), HRA-Pharma (KGD) and Mithra (KGD). JH is on the medical advisory board of NaturalCycles, serves on the international advisory board of Finox and has received honoraria for giving presentations related to infertility treatments in meetings arranged by MSD, Merck and Ferring. JT declares explicitly that there are no conflicts of interest in connection with this article.

Additional information

Funding

The study was funded by NaturalCycles Nordic AB.