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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Health-related behavior changes using IoHT for pregnant and postpartum women: From the Be- TWINKLE study ⋆</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Lian Cao</string-name>
          <email>xli-cao@kddi.com</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Masato Taya</string-name>
          <email>ma-taya@kddi.com</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Yuko Sakamoto</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Yuka Honda</string-name>
          <email>yukahon@sfc.keio.ac.jp</email>
          <xref ref-type="aff" rid="aff3">3</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Sayuri Hukuda</string-name>
          <xref ref-type="aff" rid="aff4">4</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Yuichi Sato</string-name>
          <email>s-fukuda@sato-hospital.gr.jp</email>
          <email>u-1@sato-hospital.gr.jp</email>
          <xref ref-type="aff" rid="aff4">4</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Jin Nakazawa</string-name>
          <email>jin@sfc.keio.ac.jp</email>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Juntendo University Nerima Hospital</institution>
          ,
          <addr-line>3-1-10 Takanodai, Nerima-ku, Tokyo 177-8521</addr-line>
          <country country="JP">Japan</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>KDDI Research, Inc.</institution>
          ,
          <addr-line>The Okura Presting Tower, 2-10-4 Toranomon, Minato-ku, Tokyo 105-0001</addr-line>
          <country country="JP">Japan</country>
        </aff>
        <aff id="aff2">
          <label>2</label>
          <institution>Keio University Faculty of Environment of Information Studies</institution>
          ,
          <addr-line>5322 Endo, Fujisawa-shi, Kanagawa 252-0882</addr-line>
          <country country="JP">Japan</country>
        </aff>
        <aff id="aff3">
          <label>3</label>
          <institution>Keio University Graduate school of Media Design</institution>
          ,
          <addr-line>5322 Endo, Fujisawa-shi, Kanagawa 252-0882</addr-line>
          <country country="JP">Japan</country>
        </aff>
        <aff id="aff4">
          <label>4</label>
          <institution>Sato Hospital</institution>
          ,
          <addr-line>96 Wakamatsu-cho, Takasaki-shi, Gunma 370-0836</addr-line>
          <country country="JP">Japan</country>
        </aff>
      </contrib-group>
      <abstract>
        <p>Prenatal care during pregnancy not only affects the woman's own health, but also has a significant impact on the unborn child, including the normal development of the fetus and safe delivery. The health status of the postpartum woman is also the foundation underlying emotional attachment to the baby and has a influence on child-raising going forward. However, there is a lack of healthcare services to maintain and promote the health of expectant and nursing mothers, and there is a need for services that are appropriately tailored to the actual living circumstances of most women, namely, services that can be used as needed, have a low burden, and are reliable. Therefore, this study developed a smartphone application (TEKUTECH) specialized to support the health of pregnant and nursing mothers and investigated whether there were any changes in attitudes and behaviors toward health maintenance and promotion among pregnant and nursing mothers. Sixty-five expectant and nursing mothers were given lifestyle advice to promote practices supportive of good health using a smartphone application for a period of 20 to 23 weeks (from mid-pregnancy to one month postpartum), and changes in their indoor and outdoor walking behavior, sun exposure, and nutritional intake were investigated. This paper introduces the functionality of the app, the overall design of the experiment using the app, the types of data collected, and the participants' impressions and ratings of the app.</p>
      </abstract>
      <kwd-group>
        <kwd>eol&gt;pregnant and postpartum women</kwd>
        <kwd>Health-related behavior change support</kwd>
        <kwd>Healthcare application 1</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>The aim of this study was to examine the effectiveness of a behavior change model using the
Internet of Health Things (IoHT) for improving the health of pregnant and postpartum women.
This project was conducted in collaboration with Keio University as the principal investigator,
Juntendo University Nerima Hospital, KDDI Research Institute, Inc., the National Institute for
Environmental Studies, and Sato Hospital. The project was named the “Be-TWINKLE study”
(Behavior change by Trust Worthy information using INternet of health things from Keio sfc
for Ladies Expecting babies).</p>
      <sec id="sec-1-1">
        <title>1.1. Maternal health issues</title>
        <p>Managing health during pregnancy is crucial, not just for the woman's own well-being but also
for the proper development of the fetus and ensuring a safe childbirth, significantly influencing
the child's future. In recent years, there has been an increase in the incidence of gestational
diabetes, gestational hypertension, and the proportion of low-birth-weight infants (less than
2500g at birth), which are often linked to health management issues such as obesity,
underweight, nutritional imbalances, and lack of exercise before and during pregnancy. To
safeguard the health of pregnant women and their fetal development, it is vital to focus on
nutritional management and encourage appropriate exercise before and during pregnancy. In
addition, there is growing concern about the risk of rickets due to vitamin D deficiency in
newborns and infants, prompting consideration of the benefits of sunlight exposure for
pregnant women and their babies [1]. Preventive measures include ensuring adequate vitamin
D intake during pregnancy and lactation, moderate sunlight exposure, and encouraging
mothers to expose their infants to sunlight [1].</p>
      </sec>
      <sec id="sec-1-2">
        <title>1.2. Self-care for pregnant and postpartum women</title>
        <p>Over the past few years, there has been an increase in the number of smartphone apps being
developed, and research using these apps has been aimed at improving the health of pregnant
women and nursing mothers. For example, intervention studies have been conducted using the
AI health advice app “CaloMama plus” to manage the health of thin or obese women during
pregnancy [2]. Intervention studies have also shown a decrease in nutrient intake in obese
women during pregnancy, with advice being given through an app to rectify this problem [3].
Support for the physical and mental health of pregnant and parturient women is becoming
increasingly important, especially against the backdrop of an increase in low-birth-weight
babies and depression among pregnant and parturient women. Therefore, this study developed
an application specifically designed to transform and promote healthy behavior in pregnant
women (walking, nutritional intake, and sun exposure) and examined its effectiveness.</p>
        <p>In this study, we examined whether using IoHT and providing lifestyle advice to improve
the health of pregnant and parturient mothers would influence changes in their health-related
behaviors. The IMB model (Information-Motivation-Behavioral skills model) was adopted as a
background psychological theory model (see Fig 1). The IMB model was developed in an attempt
to explain HIV-related behavior change and continues to be used as a basic theory in various
behavior change domains [4, 5]. Specifically, the IMB model attempts to explain behavior
change based on three factors: “information,” “motivation,” and “behavioral skills." Regarding
the relationships among these factors, “information” and “motivation” are thought to not only
have a direct impact on behavioral change but also bring about behavioral change through the
mediation of behavioral skills [6]. In short, to improve health-related behaviors in pregnant
women (walking, nutritional intake, sun exposure), we need to provide them with information,
motivate them to maintain their health, and foster behavioral skills that enable them to adopt
healthy behaviors. We consider this an effective approach.</p>
        <p>Therefore, with the aim of activating these factors and promoting health behavior change,
the present study adopted methods commonly used as persuasion strategies [7] in healthcare
research, such as self-monitoring, rewards, information provision, and information
authoritativeness [8, 9].</p>
        <p>Firstly, "self-monitoring" involves understanding and managing one's own actions, directing
awareness toward her mental and physical states, observing the current state of her mind and
body, and being attuned to perceiving them. The benefits include the ability to comprehend
changes in her behavior, identify areas for improvement, and facilitate self-management and
goal-setting [10].</p>
        <p>Next, the effectiveness of "rewards" is a fundamental technique for controlling behavior and
motivation through the traditional concept of "the carrot and the stick," which if frequently
incorporated into many healthcare apps. In addition, the intervention strategy of
"information provision" enhances behavioral skills through the presentation of relevant
information, with an associated increase in her perceived self-efficacy.</p>
        <p>Finally, "authority of information" is a psychological phenomenon where endowing
information sources with "authority" results in the information being perceived as credible
and valid, thereby positively influencing behavioral changes.</p>
      </sec>
      <sec id="sec-1-3">
        <title>1.3. Purpose of this study</title>
        <p>
          This study used the Internet of Health Things (IoHT)2 to investigate whether it is possible to
promote health behaviors in healthy pregnant women. The goals include (
          <xref ref-type="bibr" rid="ref1">1</xref>
          ) developing a
2 In this study, by using a smartphone-based healthcare solution, which is a type of IoHT, pregnant women were
not only able to record their pregnancy progress and self-monitor but were also given advice information
appropriate to the pregnancy period and information on health management. It is thought that knowledge,
behavioral skills, and motivation will increase, leading to the promotion of healthy behavior among pregnant and
nursing mothers.
specialized app for pregnant women and (
          <xref ref-type="bibr" rid="ref2">2</xref>
          ) conducting an intervention experiment using the
app (to be used by participants between 20 weeks of pregnancy and one month postpartum). In
particular, based on the hypothesis that authoritative information can positively influence
change in health-related behavior in pregnant women, the information provided to participants
is categorized into “health information with information sources explicitly stated as being from
experts” and “health information without explicitly stating the source of the information,” with
the aim of finding out this results in a transformation of health-related behaviors.
        </p>
        <p>
          However, due to space constraints on space in this paper, we limit (
          <xref ref-type="bibr" rid="ref1">1</xref>
          ) the discussion to
introducing the development of the app and (
          <xref ref-type="bibr" rid="ref2">2</xref>
          ) summarizing the intervention experiment using
it, as well as the feedback and opinions from participants after using the app. Any discussion of
the transformative effects on health behaviors resulting from the intervention experiment is
omitted.
        </p>
        <p>Research ethics review: This study was conducted with the approval of the Juntendo
University Medical (App Research Ethics Committee roval Number: E22-0265-N01).
Clinical trial registration: This study was registered as a clinical trial (UMIN Trial ID:
UMIN000051235).</p>
      </sec>
    </sec>
    <sec id="sec-2">
      <title>2. IoHT mobile application development</title>
      <p>In this study, an iOS app named TEKUTECH (for pregnancy and postpartum health
management application) was developed by KDDI Research, Inc. with the aim of promoting
healthy behaviors in pregnant and postpartum women3. The TEKUTECH app was utilized in
an intervention study targeting this population.</p>
      <p>First, an explanation of the overall structure of the TEKUTECH app will be provided,
followed by a description of the types of data that can be collected through the app.</p>
      <sec id="sec-2-1">
        <title>2.1. Overall structure of the TEKUTECH application</title>
        <p>This app is primarily composed of a home screen, weight and advice screen, mission screen,
reward screen, and notification screen.
3 This application is intended for research purposes only and is not intended to provide services for patients in
the future.</p>
        <p>Home screen: On the “Home Screen,” users can access a guide on how to use the app, the
step levels, and the rewards earned from completing a mission. In addition, badges
corresponding to completed surveys are displayed at the bottom of the screen. For example,
when the survey for the 20th week is completed, a badge indicating the completion of that
survey is displayed, allowing users to visually track their progress in the surveys. Furthermore,
if there are notifications asking users to respond to a survey, pop-up banners appear on the
home screen, and clicking on them guides users to the survey screen.</p>
        <p>Weight and advice screen: On the “Weight and Advice Screen,” the current gestational
week and the remaining days until the expected delivery are displayed at the top of the screen.</p>
        <p>Next, when the current weight is entered, the weight variation based on the initial weight
in early pregnancy is displayed as a line graph on the "Pregnancy Weight Gain Curve" on the
screen. This not only allows the user to observe wight changes but also enables comparison
with the standard weight gain trend during pregnancy. Consequently, behavioral changes
through self-monitoring, such as promoting self-management of weight during pregnancy and
reassessing lifestyle habits, can be expected.</p>
        <p>In addition, intervention advice information is displayed at the bottom of the screen, and
there is a feature to aid in the choice of attire for the day (short sleeves/long sleeves). This allows
for the presentation of intervention advice tailored to the user’s attire.</p>
        <p>Furthermore, these pieces of advice were tailored specifically for pregnant and postpartum
women, encompassing messages aimed at promoting appropriate weight management,
maintaining a healthy diet, and encouraging exposure to sunlight according to the gestational
week. For example: "At 38 weeks pregnant: Protein, referred to as the 'main dish,' is an essential
nutrient for building the body. (omission) Natto is an easily accessible 'main dish.' It is rich in
high-quality protein, iron, and vitamin K, which are essential for bone formation. Vitamin K is
also crucial during the newborn period. Considering breastfeeding, it is advisable to start
consciously incorporating it into your diet from now on."</p>
        <p>Mission screen: On the “Mission Screen,” the number of steps taken on the current day is
displayed, along with the corresponding step level. In addition, not only the step number for
the current day but also the historical step records and achievement levels are presented in the
form of a bar graph. These features enable daily goal management and, through comparison
with past performance, can lead to long-term self-management and motivation enhancement.</p>
        <p>Reward screen: On the “reward Screen,” specific titles are awarded based on the number
of steps taken. Titles are represented by cute animal illustrations, accompanied by text
expressed in a baby-like tone (e.g., “How does a cat meow?~♪. Tell me~♪”). This presentation
creates a sense of the baby in the belly engaging in a conversation with the mother. Not only
can users review past titles on the screen, but an upcoming title is also displayed. The goals for
achieving the next title and the number of steps required to obtain it is also displayed. Such
titles are acquired based on the number of steps taken, and this is expected to have a reward
effect on participants. Additionally, information about subsequent titles is not shown on the
screen until the next title is achieved. This absence of information contributes to the activation
of participants’ curiosity, fostering a psychological effect that encourages walking behavior.
The most recently acquired title is also displayed similarly on the “Home Screen” and “Mission
Screen,” as mentioned above.</p>
        <p>Information screen: The “Information Screen” is primarily composed of two sections,
namely the “Announcement Screen” and the “Survey Screen,” and screen transitions can be
made by clicking buttons. First, the “Announcement Screen” contains details about how to use
the app (e.g., “How to input weight” or “How to input the expected date of delivery/clinic visit
date”). Next, on the “Survey Screen,” entering a specified number will display the corresponding
screen, allowing users to respond to the survey.</p>
        <p>This app offers specialized features tailored for pregnant women, unlike typical health
apps. These features include self-management of gestational weeks and due dates, monitoring
weight fluctuations displayed on the "pregnancy weight gain curve," providing health advice
tailored to pregnant and postpartum women based on gestational weeks, and acquiring
illustrative images that give the sensation of interacting with the baby in the womb. It is
believed that these features could contribute to improving the health issues faced by pregnant
and postpartum women, such as nutritional imbalances, lack of physical activity, and vitamin
D deficiency.</p>
      </sec>
      <sec id="sec-2-2">
        <title>2.2. Types of data the App can collect</title>
        <p>In this app, user behavioral data are collected within the permitted scope, including location
information, Wi-Fi connection details, step count, and app operation history. When location
information is recorded, the data are transmitted to the server. In the event of transmission
failure, retransmission is attempted at the next recording interval. The details of the collected
data are described below.</p>
        <p>Location information: Location-related information includes the recording of GPS data and
Wi-Fi access point information4. The recording occurs when the operating system detects the
movement of the smartphone, and there is an approximate error of 100 m in the GPS data.</p>
        <p>Step count: When recording location information, the step count from midnight to the
current time is obtained using an API5 and saved to a file.
4 In this study, the acquired location information is processed to prevent the identification of individuals and is
used for effectiveness verification.
5 To obtain walking data, This app uses the API called CMPedometer on iPhone to retrieve step counts.</p>
        <p>App operation history: Every time a participant interacts with the app, their operation
history is recorded.</p>
      </sec>
    </sec>
    <sec id="sec-3">
      <title>3. Research method</title>
      <sec id="sec-3-1">
        <title>3.1. Participants</title>
        <p>This study recruited pregnant women who visited the Juntendo University Nerima Hospital, a
collaborative research facility, between December 2022 and August 2023. A total of 69
individuals consented to participate in the study. However, 4 participants withdrew from the
study based on the discontinuation criteria outlined below. Ultimately, the study focused on 65
pregnant women (mean age: 33.32 years, Standard deviation: 4.63). These participants met the
eligibility criteria and were healthy pregnant women who did not meet any of the exclusion
criteria.</p>
        <p>
          Eligibility criteria: This study established the following criteria for eligibility: (
          <xref ref-type="bibr" rid="ref1">1</xref>
          ) Less
than 20 weeks pregnant (15-19 weeks) at the time of obtaining consent; (
          <xref ref-type="bibr" rid="ref2">2</xref>
          ) A pre-pregnancy
Body Mass Index (BMI) between 18.5kg/m2 and 24.9 kg/m2; (
          <xref ref-type="bibr" rid="ref3">3</xref>
          ) Singleton pregnancy; (4) Regular
use of an iPhone; (5) Agreed to undergo all prenatal check-ups to 1 month postpartum at the
research facility
        </p>
        <p>
          Exclusion criteria: In this study, the following criteria were established for exclusion: (
          <xref ref-type="bibr" rid="ref1">1</xref>
          )
Individuals aged under 20 years; (
          <xref ref-type="bibr" rid="ref2">2</xref>
          ) Those with a multiple pregnancy; (
          <xref ref-type="bibr" rid="ref3">3</xref>
          ) Individuals not using
an iPhone with iOS 14.1 or later; (4) Individuals diagnosed with diabetes before pregnancy or
with evident diabetes during pregnancy; (5) Individuals with any other medical condition or
complication requiring nutritional counseling; (6) Those with a pre-pregnancy BMI&lt;18.5kg/m2
or BMI 25kg/m2; (7) Individuals unable to communicate in Japanese; (8) Cases where the
attending physician deemed the individual inappropriate for inclusion in this study.
        </p>
        <p>
          Discontinuation criteria: This study established the following criteria for
discontinuation: (
          <xref ref-type="bibr" rid="ref1">1</xref>
          ) If a research participant expresses a desire to withdraw from participation
or revokes consent; (
          <xref ref-type="bibr" rid="ref2">2</xref>
          ) If the entire study is discontinued; (
          <xref ref-type="bibr" rid="ref3">3</xref>
          ) In the opinion of the principal
investigator and research collaborators, it is deemed appropriate to terminate the study.
        </p>
      </sec>
      <sec id="sec-3-2">
        <title>3.2. Study period</title>
        <p>The research period for this project extended from the research implementation approval date
at each collaborating institution to September 30, 2025. Within this time frame, the registration
and observation periods for the study participants were as follows:

</p>
        <sec id="sec-3-2-1">
          <title>Registration Period: December 17, 2022, to October 31, 2023</title>
          <p>Observation Period: December 17, 2022, to September 30, 2024</p>
          <p>The study participants received intervention through the TEKUTECH app from the day
consent was obtained for participation in the research until postpartum. At the one-month
postpartum check-up, an explanation regarding the conclusion of research participation was
given, and the participant was thanked for engaging in the study, marking the conclusion of
the study.</p>
        </sec>
      </sec>
      <sec id="sec-3-3">
        <title>3.3. Study design</title>
      </sec>
      <sec id="sec-3-4">
        <title>3.3.1. Pre-intervention</title>
        <p>This study was conducted based on the research implementation plan and was divided into
three periods: “pre-intervention,” “during intervention,” and “post-intervention” (see Fig 3).
During the pre-intervention period (up to weeks 16-19 of pregnancy), we recruited eligible
pregnant women at Juntendo University Nerima Hospital to participate in the research. The
recruitment procedure included confirming eligibility, explaining the study, obtaining consent,
and installing an intervention app for data collection (e.g., step counts, questionnaires). We
distributed the study information and consent documents through physicians, and participants
watched a video summarizing the study. After obtaining consent, we confirmed app terms,
explained features through a manual, and guided participants on how to install the app. We
informed participants that the app would collect usage history, GPS location, step counts, and
questionnaire responses and reassured them that their anonymity would be protected when
location data were processed.</p>
      </sec>
      <sec id="sec-3-5">
        <title>3.3.2. During intervention</title>
        <p>During the intervention period (week 20 of pregnancy until childbirth), activities involved
grouping participants, measuring various data on physiology, behavior, psychology, and health,
and responding to participant inquiries. Eligibility criteria were confirmed before week 20, and
participants were randomly assigned to two groups (with or without authoritative information)
using the block substitution method. This method involved creating blocks of four items,
generating six random patterns, and randomly assigning participants. The allocation was
managed by KDDI Research Institute, ensuring blinded interactions at Juntendo University
Nerima Hospital, which only received participant numbers without group assignment
information.</p>
        <p>The intervention, started at week 20 of pregnancy and continued for approximately 5 months
until childbirth, while similar advice messages were given to both groups. However, the group
with authoritative information received messages accompanied by an illustrative image of the
information source, unlike the group that did not receive authoritative information, which
underwent the intervention without knowledge of the source.</p>
        <p>The intervention advice is based on the IMB model and consists of elements related to
“information,” “motivation,” and “behavioral skills” for weight management, dietary habits, and
sun exposure, respectively (see Fig 1). The information advice included guidance on appropriate
weight (BMI) during pregnancy, foods containing vitamin D, and the effects of sunlight
exposure. The motivation advice included messages to increase motivation for proper weight
management, healthy dietary habits, and sun exposure. The behavioral skills advice included
effective methods for achieving proper weight management, maintaining a healthy diet, and
practicing sun exposure.</p>
        <p>The intervention advice, totaling 99 separate pieces of advice, was created to be provided
over a period of 22 weeks (from week 20 to week 41 of pregnancy). The breakdown includes 66
pieces of advice for weight management (3 weight categories: low/standard/high×22weeks), 22
for dietary habits, 9 for sun exposure (3 time periods: 0:00-12:29/12:30-17:29/17:30-23:59×3
weather conditions: sunny/cloudy/rainy). The advice for health management and dietary habits
was developed by a health informatics expert from Keio University Graduate School (4th author
in this paper), and the sun exposure advice was created by an orthopedic surgeon from Juntendo
University Nerima Hospital Orthopedic Department (3rd author in this paper). All contents
were overseen by Sato Hospital.</p>
        <p>Sun exposure recommendations were adjusted based on seasons categorized into three
types: May to September (months with strong UV rays), April and October (months with
moderate UV rays), and November to March (months with weak UV rays). Taking into account
factors such as clothing (short/long sleeves) and weather conditions (sunny/cloudy/rainy), the
recommended sun exposure time contained in intervention messages was modified 6 . For
example, on a sunny day in September with strong UV rays, if wearing short sleeves, the
recommended sun exposure time is approximately 10 min, while wearing long sleeves on the
same day would suggest a relatively longer sun exposure time of around 19 min.</p>
      </sec>
      <sec id="sec-3-6">
        <title>3.3.3. Post-intervention</title>
        <p>The post-intervention period comprised the month following childbirth, during which
appgenerated behavioral data and survey responses were continuously collected. However, the
provision of intervention advice through the app was discontinued. Specifically, when Juntendo
University Nerima Hospital provided participant childbirth information to the KDDI Research
Institute, the system registered the childbirth information. As a result, participants received a
message on the app saying, “Congratulations on the birth of your child,” and the advice
provided during pregnancy was hidden.
6 The sun exposure duration for long-sleeved attire was calculated by categorizing the recommended past
ultraviolet exposure times derived from environmental research. This utilized minute-by-minute data from
November 21, 2013, to December 31, 2019, in Tsukuba, Japan. The data were classified on the basis of various
conditions such as month (12 months), time of day (morning, afternoon), and weather conditions (clear, cloudy,
rainy). Median values were then computed. Subsequently, when corresponding to the conditions of month,
weather, and time, the respective median values were presented as the recommended sun exposure duration. For
short-sleeved attire, half of the corresponding median value was suggested as the sun exposure duration.</p>
      </sec>
      <sec id="sec-3-7">
        <title>3.4. Collected data</title>
        <p>During the period from the date of obtaining research participant consent (at the 16th to 19th
week prenatal check-up) to the one-month postpartum check-up, various data were collected.
The data were categorized into those directly obtained at Juntendo University Nerima Hospital
and those acquired through the app.</p>
      </sec>
      <sec id="sec-3-8">
        <title>3.4.1. The data collected at the hospital</title>
        <p>At Juntendo University Nerima Hospital, various data were collected, including physiological
data (e.g., blood tests, bone density, weight, body composition, blood pressure measurements),
dietary and nutrition information, paper-based surveys, and foundational pregnancy data
(medical records).
(A) Physiological data
Blood test: During routine prenatal check-ups, blood samples were collected for hemoglobin
analysis. And another 10 ml of blood was used for serum albumin, serum alkaline phosphatase,
serum zinc, serum intact parathyroid hormone, serum 25-hydroxyvitamin D [s25(OH)D], serum
7 Translation of advice in the figure:On the morning of July 7, approximately 4 min of sunbathing can produce a
day’s worth of vitamin D. Let us expose our skin directly, such as by rolling up sleeves, and actively soak up the
sun.
calcium, and serum phosphorus. s25(OH)D was also analyzed using 3ml of blood collected from
the umbilical cord at the time of delivery.</p>
        <p>Bone density measurement: We measured bone strength of calcaneus by quantitative
ultrasound (QUS) measurements of bone speed of sound (SOS). The measurement, lasting
approximately 3 minutes, [A-1000EXP, GE Healthcare Japan].</p>
        <p>Body composition measurement: During the waiting time at the prenatal check-up, we
used a bioelectrical impedance analysis (BIA) method body composition analyzer (The Tanita
Professional Body Composition Analyzer, MC190EM) to measure the body fat percentage, fat
mass, and lean body mass for the whole body and specific regions. The measurement took
approximately 30 seconds.</p>
        <p>Weight and blood pressure: During the waiting period for the prenatal check-up, we
measured weight and blood pressure using hospital scales and blood pressure monitors.
(B) Paper-based questionnaire survey
Dietary and nutritional data: During the waiting period for prenatal check-ups, participants
were asked to respond to a paper-based, self-administered questionnaire, specifically, the
Brieftype Self-Administered Diet History Questionnaire (BDHQ) [11]. During the 1-month
postpartum checkup, to shorten the length of hospital stay, the participants took the
questionnaire home, answered it, and returned it via a reply-paid envelope. The completion of
the questionnaire required approximately 20 min.</p>
        <p>Japanese version of the Edinburgh Postnatal Depression Scale (EPDS): The scores
from the Edinburgh Postnatal Depression Scale (10 items) questionnaire [12] administered
during the 1-month postpartum checkup were extracted from the electronic medical records.</p>
        <p>Mother-to-Infant Bonding Scale (MIBS): Administered under the guidance of a midwife
during prenatal checkups, the questionnaire includes 10 items such as “feeling affectionate
towards the baby” and “feeling irritated by the baby.” Reactions were measured on a 4-point
scale, with higher scores indicating stronger negative feelings toward the baby [13]. In
particular, in cases of elevated negative emotions, the midwife provided psychological
counseling.
(C) Basic pregnancy-related data
Obtained recorded data from medical records including delivery date, pre-delivery weight,
delivery method, bleeding volume, newborn’s length and weight, gender, infant’s survival
status, presence of gestational diabetes, and presence of gestational hypertension (with
information on antihypertensive medication if applicable).</p>
      </sec>
      <sec id="sec-3-9">
        <title>3.4.2. The data collected from the app</title>
        <p>Next, we obtained behavioral data (e.g., step counts and app usage history) and survey response
data (time spent outdoors, sun exposure, bone literacy, psychological factors, feedback on
research participation etc.) through the app.
(D) Behavioral data
The app logs measure location data (GPS and Wi-Fi connect information), step counts, and
usage history of the TEKUTECH app. Using this data enables the calculation of the following
behavioral metrics.</p>
        <p>Location data: Using GPS and Wi-Fi connected information from the device, the
participant’s location data were obtained, allowing determination between indoor and outdoor
settings (at home and outside). With these data, it became possible to calculate outdoor duration
and frequency. Moreover, when combined with step count records, it enabled the calculation of
the number of steps taken indoors and outdoors. Additionally, by combining location data with
outdoor time data, daily UV exposure can be calculated8, contributing to the verification of the
effects of sun exposure on the participants.</p>
        <p>Step count records: These records can be used to examine variations in the walking
behavior of pregnant and postpartum women and to assess the effectiveness of interventions.</p>
        <p>App viewing frequency: Data from the TEKUTECH app’s browsing history make it
possible to calculate the frequency of viewing each screen, thereby providing a means to assess
the effectiveness of interventions.
(E) App-based survey
UV exposure survey: A retrospective survey lasting approximately 1 min was conducted to
ascertain the time participants usually spent outdoors and sunscreen cream usage. This data,
combined with data on the presence or absence of outdoor activities and the duration of outdoor
exposure calculated from app logs, will enable the verification of the intervention effects of a
participant’s sun exposure.</p>
        <p>Bone literacy survey: A unique set of questions was created to measure knowledge and
behaviors related to bones, and a response survey lasting approximately 1 min was conducted.</p>
        <p>Self-Care Motivation Scale: The Self-Care Motivation Scale [14] was used to measure the
motivation for self-care related to overall health. For example, items such as “I am willing to try
to be healthy” and “To be healthy, it is important to be patient" were measured using a 6-point
scale with 4 items. Higher scores indicate higher motivation.</p>
        <p>Self-Management Skills Scale: The Self-Management Skills Scale [15] was used to measure
self-management related to health. Items such as “When trying to do something, gather enough
information” and “When executing something, make your own plan” were measured using a
4point scale with 10 items. Higher scores indicate higher self-management skills.</p>
        <p>
          Evaluation and feedback after study participation: In the final 1-month postpartum
survey, additional items were included to assess participants’ feelings during app usage.
Specifically, the following items were measured using a 5-point scale: (
          <xref ref-type="bibr" rid="ref1">1</xref>
          ) Was the advice
helpful? (
          <xref ref-type="bibr" rid="ref2">2</xref>
          ) Was the advice reliable? (
          <xref ref-type="bibr" rid="ref3">3</xref>
          ) Did the advice feel like it came from an expert? (4) Was
the content of the advice easy to understand? (5) Would you want to use this app again in a
future pregnancy?
        </p>
        <p>Higher ratings indicate a more positive evaluation. The results are presented in Figure 5 in
the order of usefulness, reliability, expertise, understandability, and future use. in addition,
participants were asked if they took action on the basis of the advice (4-point scale). Finally,
8 The ultraviolet exposure level is an indicator that represents the extent to which an individual has been exposed
to ultraviolet radiation.
participants were free to provide comments on what they liked and any difficulties encountered
during their participation in the study.</p>
      </sec>
      <sec id="sec-3-10">
        <title>3.5. Data acquisition</title>
        <sec id="sec-3-10-1">
          <title>The timing of data acquisition for various types of data is shown in Figure 4.</title>
        </sec>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>4. Results and discussion</title>
      <p>In this study, we developed the TEKUTECH app specifically for pregnant women to promote
healthy behaviors. The intervention targeted pregnant women from mid-pregnancy to 1 month
postpartum, covering approximately 20-23 weeks. Due to space constraints, we omit the details
of the intervention’s effects on changing maternal health-related behavior. Instead, this paper
focuses on the assessments and feedback from participants who used the app. Specifically, we
compiled responses from 36 participants who completed the postpartum 1-month survey by
October 31, 2023. As shown in Figure 5, the average ratings based on the app users’ assessments
exceeded the midpoint of 3 (neither agree nor disagree), indicating a relatively positive trend in
participant evaluations.</p>
      <p>Next, feedback after usage was categorized into positive aspects and challenges. First,
regarding positive aspects, four main dimensions were identified:



</p>
      <p>Acquisition of Knowledge and Information: Participants highlighted gaining necessary
information and acquiring new knowledge (e.g., “I obtained the information I needed”
and “I gained new knowledge.” 9 responses).</p>
      <p>Increased Health Awareness: Users reported heightened awareness of health
management, such as consciously monitoring weight and step counts (e.g., “I became
conscious of managing weight and steps” and “My awareness of health has increased.”
7 responses).</p>
      <p>Effectiveness of Weight Management: Respondents expressed satisfaction with the ease
of weight management and the significant utility of daily weight tracking (e.g., “Weight
management was easy” and “Daily weight management was very helpful.” 6 responses).
Motivation for Healthy Living and Exercise: Participants indicated that the app served
as a motivation for maintaining a healthy lifestyle, particularly in terms of walking (e.g.,
“It became a motivation for a healthy life” and “Managing steps and earning badges
motivated me to walk.” 6 responses).</p>
      <p>These results demonstrate the positive impact of the intervention design, focusing on
selfmonitoring, rewards, and suggestions, achieving psychological effects such as increased
motivation, interest, and self-efficacy in promoting healthy behaviors.</p>
      <p>However, some challenges were reported, which are categorized as follows:
</p>
      <p>Issues with Step Count Records: Some participants mentioned occasional inaccuracies
in step count records, making it difficult to rely on the app as a daily pedometer (e.g.,
"There were occasional discrepancies in step counts, making it unreliable on certain
days." 2 responses).

</p>
      <p>Difficulty with Continuous App Operation: Respondents expressed the difficulty of
keeping the app running continuously, describing it as stressful to always have it active
(e.g., "There was pressure to keep it open all the time." 2 responses).</p>
      <p>Other Challenges: Participants also highlighted burdens, inconveniences in data input,
and requests for feedback on the study as additional challenges.</p>
      <p>These comments provide insights into areas that may require improvement, such as
addressing technical issues, reducing operational burdens, and enhancing user experience based
on participant feedback.</p>
      <p>In this study, we addressed the significant issue of maternal health management, which has
not been adequately examined thus far, by developing a smartphone application aimed at
promoting health. We confirmed its usefulness, reliability, and usability. Specifically, what kind
of application did we develop, and what empirical research did we conduct using it? What were
the participants' feelings about using the app? We focused on these questions in our discussion.
However, descriptions of the effects and outcomes of the intervention, such as changes in
attitudes and behaviors of pregnant and postpartum women and improvements in health status,
were insufficient. We will provide detailed descriptions of these aspects in future papers.</p>
    </sec>
    <sec id="sec-5">
      <title>Acknowledgements</title>
      <p>We sincerely thank Professor Taiki Ogishima and Associate Professor Yojiro Maruyama of the
Juntendo University Nerima Hospital for their invaluable support in recruiting participants and
conducting this research. We would also like to extend our deep appreciation to Senior
Researcher Hideaki Nakajima of the National Institute for Environmental Studies, Center for
Global Environmental Research, for his assistance in measuring ultraviolet radiation exposure
(extent of sun exposure).
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