Published October 2017The European Journal of Contraception & Reproductive Health Care : the Official Journal of the European Society of Contraception, 22(5), 396-397
Frank-Herrmann, P., Stanford, J. B., & Freundl, G. (2017). Fertility awareness-based mobile application. The European Journal of Contraception & Reproductive Health Care : the Official Journal of the European Society of Contraception, 22(5), 396-397. https://doi.org/10.1080/13625187.2017.1362691
Frank-Herrmann P, Stanford JB, Freundl G. Fertility awareness-based mobile application. Eur J Contracept Reprod Health Care. 2017;22(5):396-397. doi:10.1080/13625187.2017.1362691
Frank-Herrmann, Petra, et al. "Fertility awareness-based mobile application." The European Journal of Contraception & Reproductive Health Care : the Official Journal of the European Society of Contraception, vol. 22, no. 5, 2017, pp. 396-397.
Department of Gynaecological Endocrinology and Fertility Disorders, University of Heidelberg, Vossstrasse 9, 69115 Heidelberg, Germany. petra.frank-herrmann@med.uni-heidelberg.de038t36y30
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RRM Academy Synopsis
FABM experts judge NaturalCycles app rates unreliable for comparison
In a 2017 letter, three FABM researchers state that an app study's pregnancy rates are not reliable for comparison with other studies. The authors call its perfect-use rate inappropriate and highly misleading.
Key Findings
The study included only women with at least 3 months of app access. The letter identifies possible selection bias, since excluding an initial learning period may bias fertility awareness-based methods (FABM) research.
Pregnancy was judged from daily app data for most women. The letter states that no criteria were given and that the results were not compared with the pregnancy tests the women entered.
Information on intercourse was available for only 8% of days, yet the study's perfect-use estimate placed all cycles in the denominator. The letter states that this greatly lowers the estimate.
Of 1194 women answering a retrospective question on intentions (29% of women in the study), 21 reported trying to achieve pregnancy. The letter states that it is unclear whether they were excluded.
The letter states that few of the FABM studies cited are appropriately comparable. The lowest typical-use pregnancy rates for FABM, 1.8 per 100 women at 1 year, are reported for Sensiplan.
Interpretation
The letter to the editor appraises a published study of the NaturalCycles app, which reported unplanned pregnancy among its users. The app reads daily basal body temperature with a proprietary algorithm to find the fertile window. The authors applaud the publication of outcome data and credit a sensitivity analysis of 61 women with no pregnancy data. They state that current data are insufficient to establish the algorithm's precision and accuracy. In their opinion, the standards used for FABM should apply equally to new apps.
RRM Context
Restorative reproductive medicine relies on cycle charting. Clinicians read the signs that a woman or couple records to find ovulation and the fertile days. The letter cites a prospective study of Sensiplan, a German sympto-thermal method, that followed couples and their sexual behavior in the fertile time.
Our editorial summary of this paper, not the article's abstract.
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