“Rakuten Kirei-do-Navi” Releases Findings of Study on Women’s Hormonal Balance

Tokyo, October 24, 2014 – Rakuten, Inc. and Toshiba Corporation today released the findings of a study and analysis of data derived from the “Basal Body Temperature (BBT) Type Determination” and “Hormone Balance Check-up” features available on the companies’ joint service for women, “Rakuten Kirei-do-Navi,” a smartphone-based basal body temperature tracking service which is synced to a specially designed basal body thermometer.

In an age of increasing professional engagement by women in society, it is important for women to monitor their own hormone balance from the point of view of personal health. The BBT Type Determination feature examines a woman’s BBT graph chart based on BBT measurements taken throughout a single menstrual cycle. The shape of the graph corresponds to one of the six BBT types as developed by Yasunori Yoshimura, a Kirei-do-Navi advisor and Professor Emeritus of Keio University. The “Yoshimura 6 BBT Types” are: “Clear two-tier”; “Slow rise”; “Zigzag in high temperature phase”; “Long low-temperature phase”; “Short high-temperature phase” and “Non two-tier.” Furthermore, the new “Hormone Balance Check-up” feature analyzes users’ hormone balance based on the BBT Type Determinations made for three successive menstrual cycles. This lets women know their hormonal balance according to a three (3) color system: “Green” indicates a sound hormone balance; “Yellow” indicates an unsteady hormone balance; and “Red” indicates a balance of concern. These two features help women to better understand their own BBT graph and hormone balance.

This study was carried out from July 1 to September 30, 2014 based on data from Kirei-do-Navi members between the ages of 25 and 44 who recorded their BBT data for more than a set period of time, and as such, the sample size is not disclosed. Overall statistical values are calculated by weighting into five-year age groups in Japan between the ages of 25 and 44 (Ministry of Internal Affairs and Communications demographic survey as of October 1, 2013).

Only one in three women had the ideal “Clear two-tier” type
The study of the distribution of the BBT types of the entire sample showed that only one in three women had the ideal, stable, “Clear two-tier” type hormone balance. At roughly 40% of the entire sample, the most common type observed was the “Zigzag in high-temperature phase” type. In this type, body temperature during the high-temperature phase is unstable and occasionally drops. Women of the “Zigzag in high-temperature phase” type do not secrete the corpus luteum hormone in a stable manner, and could find it difficult to become pregnant. Possible causes include lack of daily routine, stress, and poor circulation.

Around 10% of women in the 25-29 age category had the “Non two-tier” type
According to the study, approximately 10% of women between the ages of 25 and 29 had unsteady hormone secretions and belonged to the “Non two-tier type,” suggesting they might not be ovulating. Health issues and menstrual cycle irregularities can be caused by hormonal imbalances.

One in ten women in the 25-29 age category had a “balance of concern”
The result of “Hormone Balance Check-up” feature by age group revealed that 10% of women in the 25-29 age group had a “balance of concern”, the highest percentage of any age group. This age group also had the lowest number of green results (sound hormone balance).

Overview of Study
Area: Nation-wide
Sample population: Women between the ages of 25 and 44
Eligibility: Kirei-do-Navi members between the ages of 25 and 44 who entered their BBTdata for at least a set period of time between July and September 2014. Sample size not disclosed. *Data processed without identification of individuals
Duration: July 1 to September 30, 2014
Implementer: Rakuten Kirei-do-Navi

The result of the survey and analysis, complete with graphs, are available in Japanese at the following link: http://kidona.rakuten.co.jp/new/news141024/