A Comparison of User Behaviors for a Fertility-Tracking App: Does Training in an NFP Method Improve Persistence and Use?

A Comparison of App-Defined Fertile Days from Two Fertility Tracking Apps using Identical Cycle Data

OBJECTIVE

The Natural Cycles app employs daily basal body temperature to define the fertile window via a proprietary algorithm and is clinically established effective in preventing pregnancy. We sought to i) compare the app-defined fertile window of Natural Cycles to that of CycleProGo™, an app that uses BBT and cervical mucus to define the fertile window and ii) compare the app-defined fertile windows to the estimated physiologic fertile window.

STUDY DESIGN

Daily BBT were entered into Natural Cycles from 20 randomly selected regularly cycling women with at least 12 complete cycles from the CycleProGo database. The proportion of cycles with equivalent (+/-1 cycle day) fertile-window starts and fertile-window ends was determined. The app -defined fertile windows were then compared to the estimated physiologic fertile window using Peak mucus to estimate ovulation.

RESULTS

Fifty seven percent of cycles (136/238) had equivalent fertile-window starts and 36% (72/181) had equivalent fertile-window end days. The mean overall fertile-window length from Natural Cycles was 12.8 days compared to 15.1 days for CycleProGo (p<0.001). The Natural Cycles algorithm declared 12%-30% of cycles with a fertile-window start and 13%-38% of cycles with a fertile-window end within the estimated physiologic fertile window. The CycleProGo algorithm declared 4%-14% of cycles with a fertile-window start and no cycles with a fertile-window end within the estimated physiologic fertile window.

CONCLUSIONS

Natural Cycles designated a higher proportion of cycles days as infertile within the estimated physiologic fertile window than CycleProGo.

IMPLICATIONS

Use of cervical mucus in addition to BBT may improve the accuracy of identifying the fertile window. Additional studies with other markers of ovulation and the fertile window would give additional insight into the clinical implications of app-defined fertile window differences.

Menstrual Cycle Tracking Applications and the Potential for Epidemiological Research: A Comprehensive Review of the Literature

Purpose of review

We reviewed published studies on menstrual cycle tracking applications (MCTAs) in order to describe the potential of MCTAs for epidemiologic research.

Recent Findings

A search of PubMed, Web of Science, and Scopus for MCTA literature yielded 150 articles. After exclusions, there were 49 articles that addressed the primary interest areas: 1) characteristics of MCTA users in research, 2) reasons women use or continue using MCTAs, 3) accuracy of identifying ovulation and utility at promoting and preventing pregnancy, and 4) quality assessments of MCTAs across several domains.

Summary

MCTAs are an important tool for the advancement of epidemiologic research on menstruation. MCTA studies should describe the characteristics of their user-base and missing data patterns. Describing the motivation for using MCTAs throughout a user's life and validating the data collected should be prioritized in future research.