May 20, 2014
  • Rakuten, Inc.
  • Toshiba Corporation

Rakuten and Toshiba Release Findings of Women’s Hormonal Balance Analysis

Analysis Based on New “Announcement Basal Body Temperature Type Determination”
and “Hormone Balance Check-up” Features

Tokyo, May 20, 2014 – Rakuten, Inc. (“Rakuten”) and Toshiba (“Toshiba”) Corporation today released the findings of their study of the hormonal balance of women. The study was carried out using the newly-added “Basal Body Temperature (BBT) Type Determination” and “Hormone Balance Check-up” features available on the companies’ jointly developed service for women, “Rakuten Kirei-do-Navi” (Advisor: Yasunori Yoshimura, Professor Emeritus, Keio University), which provides information based on basal body temperature (BBT).

Kirei-do-Navi provides women with useful information to help enhance their beauty and health. It does this by tracking and analyzing BBT data collected through a specially designed thermometer that syncs wirelessly with the app installed on the user’s smart device. The newly added “BBT Type Determination” feature examines a woman’s BBT graph chart based on BBT measurements taken throughout a single menstrual cycle. The app then identifies which of the six (6) BBT types correspond to each woman. Developed by Yasunori Yoshimura, a Kire-do-Navi advisor, “Yoshimura’s 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 hormone 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 features help women to better understand their own BBT graph and hormone balance.

Rakuten and Toshiba conducted an analysis using these new functions from March 12, 2013 to March 12, 2014, using data obtained from 1,000 randomly selected Kirei-do-Navi members between the ages of 25 and 44 (250 women in each five-year age group) who entered their BBT data for at least a certain period of time.

This analysis used data from which individuals are not identifiable.

Summary of Analysis Findings

■ Only one in three women had the ideal “clear two-tier” type
A 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 is unstable and occasionally drops during the high-temperature phase. 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.  

■ Around 10% of women in the 25-29 age category had the “Non two-tier” type
According to the analysis approximately 10% of women between the ages of 25 and 29 had unsteady hormone secretions and belonged to the “Non two-tier type,” suggesting the women may not be ovulating. Possible causes include lifestyle, such as an unhealthy diet or stressful work, which can make stable hormone secretion more difficult.      

■ The younger women are, the less steady their hormonal balance is
Breaking down the color codes by age group indicated that women between the ages of 25 and 29 had the highest number of reds, the danger zone level. In this age group, 28% of women were grouped in the red level, 10% more than the sample average.   

Analysis Outline
Analysis area : Nation-wide
Sample population : Women between the ages of 25 and 44
Sample size : 1,000 women who used the new “Hormone Balance Check-up” feature (250 women in each five-year age group)
Duration : March 12, 2013 to March 12, 2014
Implementer : Rakuten Kirei-do-Navi

The analysis, the analysis findings and report, complete with graphs, are available at the following link:

*Please note that the information contained in press releases is current as of the date of release.

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