Fertility Awareness · Effectiveness

Can apps and calendar methods predict ovulation with accuracy?

Johnson S, Marriott L, Zinaman M

Published May 12, 2018 Current Medical Research and Opinion, 34(9), 1587-1594
DOI 10.1080/03007995.2018.1475348 PMID 29749274

Abstract

Objective

The accuracy of prediction of ovulation by cycle apps and published calendar methods was determined by comparing to true probability of ovulation.

Methods

A total of 949 volunteers collected urine samples for one entire menstrual cycle. Luteinizing hormone was measured to assign surge day, enabling probability of ovulation to be determined across different cycle lengths. Cycle-tracking apps were downloaded. As none provided their methodology, four published calendar-based methods were also examined: standard days, rhythm, alternative rhythm and simple calendar method. The volunteer ovulation data was applied to the app/calendar methods to determine their accuracy.

Results

Mean cycle length was 28 days (range: 23-35); 34% of women believed they had a 28-day cycle, but only 15% did. No LH surge was seen for 99 women. Most likely day of ovulation for a 28-day cycle was day 16 (21%). Accuracy of ovulation prediction was no better than 21% by the apps. The standard days and rhythm methods were most likely to predict ovulation (70% and 89%, respectively) but had very low accuracy.

Conclusions

Ovulation day varies considerably for any given menstrual cycle length, thus it is not possible for calendar/app methods that use cycle-length information alone to accurately predict the day of ovulation. National Clinical Trial Code: NCT01577147. Registry website: www.clinicaltrials.gov .

Topics

By this author

Related research

Fertility Awareness › Effectiveness › Comparative Effectiveness · Menstrual Cycle › Cycle Biomarkers › Hormonal Markers
Sarah Johnson, Lorrae Marriott
S Johnson, L Marriott
PMID 29749274 29749274 DOI 10.1080/03007995.2018.1475348 10.1080/03007995.2018.1475348 Johnson et al. 2018, Johnson 2018

Cite this article

Johnson, S., Marriott, L., & Zinaman, M. (2018). Can apps and calendar methods predict ovulation with accuracy? Current Medical Research and Opinion, 34(9), 1587-1594. https://doi.org/10.1080/03007995.2018.1475348