Digital fertility awareness-based contraception offers an alternative choice for women who do not wish to use hormonal or invasive methods. The aim of this study was to investigate the key demographics of current users of the Natural Cycles app and assess the contraceptive outcomes of women preventing pregnancy in a UK cohort of women.
Materials and Methods
This was a real world observational prospective observational study. The typical-use effectiveness of the method was calculated using both 13-cycle cumulative probability of pregnancy (life table analysis) and Pearl Index for the entire study cohort. Perfect-use PI was calculated using data from cycles where sexual intercourse during the fertile window was marked as protected and no unprotected sex was recorded on fertile days.
Results
12,247 women were included in the study and contributed an average of 9.9 months of data for a total of 10,066 woman years of exposure. The mean age of the cohort was 30, mean BMI 23.4, the majority were in a stable relationship (83.2%) and had a university degree or higher (83%). The one year typical use, PI was 6.1 (95% CI: 5.6, 6.6) and with perfect-use was 2.0 (95% CI: 1.3, 2.8). 13 cycle pregnancy probability was 7.1%.
Conclusions
This is the first study which describes the use of a digital contraceptive by women in the UK. It describes the demographics of users and how they correlate with the apps effectiveness at preventing pregnancy.
Natural Cycles app contraceptive effectiveness UK cohort, digital fertility awareness contraception Pearl Index, Natural Cycles typical use perfect use pregnancy rate, fertility awareness-based method app real world effectiveness, digital contraception demographic analysis UK women, Natural Cycles 13 cycle cumulative pregnancy probability, smartphone fertility app contraceptive outcomes prospective study, non-hormonal contraception digital fertility tracking effectiveness, Scherwitzl Natural Cycles observational study, fertility awareness app life table analysis pregnancy risk
PMID 33539252 33539252 DOI 10.1080/13625187.2020.1867844 10.1080/13625187.2020.1867844
Cite this article
Pearson, J. T., Chelstowska, M., Rowland, S. P., Mcilwaine, E., Benhar, E., Berglund Scherwitzl, E., Walker, S., Gemzell Danielsson, K., & Scherwitzl, R. (2021). Natural Cycles app: contraceptive outcomes and demographic analysis of UK users. The European journal of contraception & reproductive health care : the official journal of the European Society of Contraception, 26(2), 105-110. https://doi.org/10.1080/13625187.2020.1867844
Pearson JT, Chelstowska M, Rowland SP, Mcilwaine E, Benhar E, Berglund Scherwitzl E, et al. Natural Cycles app: contraceptive outcomes and demographic analysis of UK users. Eur J Contracept Reprod Health Care. 2021;26(2):105-110. doi:10.1080/13625187.2020.1867844
Pearson, J. T., et al. "Natural Cycles app: contraceptive outcomes and demographic analysis of UK users." The European journal of contraception & reproductive health care : the official journal of the European Society of Contraception, vol. 26, no. 2, 2021, pp. 105-110.
Keywords
Contraceptive Agents
Related articles
Contraception/ComparisonOvarian Reserve EffectsAMH and AFCContraceptive Impact on Markers
Landersoe SK et al., 2019·Eur J Contracept Reprod Health Care
The aim of the study was to assess whether the ovarian reserve markers anti-Müllerian hormone (AMH) and antral follicle count (AFC) were lower among women using the progestin-only pill (POP) or levonorgestrel-releasing intrauterine system (LNG-IUS) and similar to the decrease observed in combined oral contraceptive (COC) pill users. This retrospective study comprised 565 hormonal contraceptive users (COC, POP, LNG-IUS or contraceptive vaginal ring) and 983 non-hormonal contraceptive users, who were seen in two Danish fertility assessment and counselling clinics between 2015 and 2019. Adjusted multiple regression analysis was used to examine the differences in AMH and AFC between hormonal and non-hormonal contraceptive users. Compared with non-hormonal contraceptive users, AMH was 31.1% lower among COC users [95% confidence interval (CI) -39.6%, -25.9%; p < 0.001], 35.6% lower among POP users (95% CI -49.0%, -18.6%; p < 0.001) and 17.1% lower among LNG-IUS users (95% CI -31.4%, 0.002%; p = 0.052); no significant differences were seen among vaginal ring users. Compared with non-hormonal contraceptive users, AFC was 31.3% lower among COC users (95% CI -35.0%, -25.3%; p < 0.001) and 29.7% lower among POP users (-39.1%, -17.9%; p < 0.001); no significant differences were seen among LNG-IUS or vaginal ring users. Ovarian volume was more than 50% reduced among COC and vaginal ring users (p < 0.001) but was unchanged among POP and LNG-IUS users. Assessment of ovarian reserve markers among users of all types of hormonal contraception should be interpreted cautiously and the type of contraceptive method considered.
Berglund Scherwitzl E et al., 2019·Eur J Contracept Reprod Health Care
The aim of the study was to compare the effect of previously used contraceptive methods on women's shortand long-term fecundity. Use of hormonal contraception (HC) was compared with the use of a contraceptive mobile application (app). 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. 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. 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.
Fertility AwarenessSmartphone ApplicationsTypical and Perfect UseFertile Window Estimation
Jennings V et al., 2019·Eur J Contracept Reprod Health Care
Dynamic Optimal Timing (Dot) is a smartphone application (app) that estimates the menstrual cycle fertile window based on the user's menstrual period start dates. Dot uses machine learning to adapt to cycles over time and informs users of 'low' and 'high' fertility days. We investigated Dot's effectiveness, calculating perfectand typical-use failure rates. This prospective, 13 cycle observational study (ClinicalTrials.gov NCT02833922) followed 718 women who were using Dot to prevent pregnancy. Participants contributed 6616 cycles between February 2017 and October 2018, providing data on menstrual period start dates, daily sexual activity and prospective intent to prevent pregnancy. We determined pregnancy through participant-administered urine pregnancy tests and/or written or verbal confirmation. We calculated perfectand typical-use failure rates using multi-censoring, single-decrement life-table analysis, and conducted sensitivity, attrition and survival analyses. The perfect-use failure rate was calculated to be 1.0% (95% confidence interval [CI]: 0.9%, 2.9%) and the typical-use failure rate was 5.0% (95% CI: 3.4%, 6.6%) for women aged 18-39 (n = 718). Survival analyses identified no significant differences among age or racial/ethnic groups or women in different types of relationships. Attrition analyses revealed no significant sociodemographic differences, except in age, between women completing 13 cycles and those exiting the study earlier. Dot's effectiveness is within the range of other user-initiated contraceptive methods.
Frank-Herrmann P et al., 2017·Eur J Contracept Reprod Health Care
Sir,Currently, a variety of start-up companies are developing mobile phone apps to track the menstrual cycle and the fertile window, for the use of women who are trying to conceive or trying to avo...