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RESEARCH ARTICLE
See How They Grow: Testing the feasibility of
a mobile app to support parents’
understanding of child growth charts
Gayl HumphreyID
1
*, Rosie Dobson
1
, Varsha Parag
1
, Marion Hiemstra
2
, Stephen Howie
3
,
Samantha Marsh
1
, Susan Morton
4
, Dylan Mordaunt
5,6
, Angela Wadham
1
, Chris Bullen
1
1National Institute for Health Innovation, Faculty of Medical and Health Science, University of Auckland,
Auckland, New Zealand, 2Plunket, National Education, Auckland, New Zealand, 3Department of
Paediatrics, Child and Youth Health, Faculty of Medical and Health Science, University of Auckland,
Auckland, New Zealand, 4Growing Up in New Zealand, Faculty of Medical and Health Science, University of
Auckland, Auckland, New Zealand, 5University of Adelaide, South Australia, Australia, 6Flinders University,
South Australia, Australia
*g.humphrey@auckland.ac.nz
Abstract
Background
Mobile devices provide new opportunities for the prevention of overweight and obesity in
children. We aimed to co-create and test an app that offered comprehensible feedback to
parents on their child’s growth and delivered a suite of age-specific information about nutri-
tion and activity.
Methods
A two-phased approach was used to co-create the digital growth tool—See How They Grow
—and test its feasibility. Phase one used focus groups (parents and professionals such as
paediatricians and midwives) and a national on-line survey to gather requirements and build
the app. Phase two involved testing the app over 12-weeks, with parents or carers of chil-
dren aged 2-years. All research activities were undertaken exclusively through the app,
and participants were recruited using social media and hard copy materials given to patents
at a child health visit.
Findings
Four focus groups and 101 responses to the national survey informed the features and func-
tions to include in the final app. Two hundred and twenty-five participants downloaded the
app, resulting in 208 eligible participants. Non-Māori/Non-Pacific (78%) and Māori (14%)
had the highest downloads. Fifty-four per cent of participants were parents of children under
6-months. These participants were more likely to regularly use the app than those with chil-
dren older than 6-months (64% vs 36%, P = 0.011). Over half of the participants entered
three measures (n = 101, 48%). Of those that completed the follow-up survey (n = 101,
48%), 72 reported that the app helped them better understand how to interpret growth
charts.
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OPEN ACCESS
Citation: Humphrey G, Dobson R, Parag V,
Hiemstra M, Howie S, Marsh S, et al. (2021) See
How They Grow: Testing the feasibility of a mobile
app to support parents’ understanding of child
growth charts. PLoS ONE 16(2): e0246045. https://
doi.org/10.1371/journal.pone.0246045
Editor: Vijayaprasad Gopichandran, ESIC Medical
College & PGIMSR, INDIA
Received: April 27, 2020
Accepted: January 11, 2021
Published: February 19, 2021
Copyright: ©2021 Humphrey et al. This is an open
access article distributed under the terms of the
Creative Commons Attribution License, which
permits unrestricted use, distribution, and
reproduction in any medium, provided the original
author and source are credited.
Data Availability Statement: Data underlying this
study cannot be made publicly available due to
restrictions imposed by the ethical approval
obtained to conduct the study. Additionally, the
National Ethics Advisory Committee Standards
(https://neac.health.govt.nz/national-ethical-
standards-health-and-disability-research-and-
quality-improvement/part-two/12-health) has set
some clear guidelines for data which involve Māori
(indigenous population) and which our study
included. The standards are guided by Te Mana
Raraunga (https://www.temanararaunga.maori.nz/
Conclusion
The app was acceptable and with minor modifications, has the potential to be an effective
tool to support parents understanding of growth trajectories for their children. A larger trial is
needed to evaluate if the app can have a measurable impact on increasing knowledge and
behaviour, and therefore on preventing childhood overweight and obesity.
Introduction
Growth during the first few years of life plays an important role in setting body mass index
(BMI) trajectories into childhood and adulthood [1,2]. Once obesity is established, it is diffi-
cult to reverse [3]. In a recent Cochrane Review of interventions to prevent childhood obesity
for children aged 0–5 years, there was moderate evidence from 16 randomised control trials
that diet and exercise combined are effective on reducing zBMI scores, although these reduc-
tions were small [4]. For example, evidence from sixteen randomised control trials that com-
bined diet and physical activity interventions for 0-5-year olds, compared with controls,
reduced zBMI (mean difference −0.07 kg/m
2
, 95% confidence interval (CI) −0.14 to −0.01).
There was little impact on zBMI for individual diet or physical activity interventions (Diet:
mean difference −0.14, 95% CI −0.32 to 0.04; Physical activity; mean difference 0.01, 95% CI
−0.10 to 0.13). A zBMI change of at least -0.25 for a clinically significant impact has been sug-
gested [5].
While these studies do not account for the role of parental perception of their child’s
weight, a recent meta-analysis exploring parental underestimates of child weight found that
50.7% (95% confidence interval 31.1%–70.2%) of parents underestimate their overweight/
obese children’s weight [6]. Other studies have also reported similar findings [7–10]. The
increase in children’s weight at a population level is clearly illustrated in a recent report, where
the median child weight now falls on the 67
th
centile rather than the 50
th
centile (1990 baseline)
[11].
Being overweight or obese in childhood is reported as a notable factor for being overweight
or obese in adolescence and adulthood [12]. Overweight and obesity have an impact across the
life course through the development of long term conditions and contributing to mental ill-
health. The economic (personal and societal) costs are also immense [13].
When parents perceive childhood overweight and obesity as a concern, they also exhibit an
inability to internalise this into their own lives [14]. Factors that contribute to parental failure
to recognise or perceive overweight in their children are complex and multifaceted. They
include parental beliefs and values of body weight, their own body weight [15], socio-eco-
nomic factors [16], environmental factors [17] and societal normalisation of overweight [18,
19]. This normalisation of overweight and obesity within society is likely to be a contributing
factor in the increase of childhood overweight and obesity [7,19–21].
Effective, evidence-based interventions that focus on how best to support parents to under-
stand their child’s growth and the influence the early years have on unhealthy weight gain is
sparse [22,23], with many studies and reports concluding that more research is needed [5,24].
Growth charts enable children’s growth to be assessed by comparing them with a normal
range for other children of the same age and gender, relative to a reference population. The
serial measurements of height, weight and head circumference, taken as a child ages, are sensi-
tive measures of their general health [24]. In many countries, growth charts are part of the par-
ent-owned or parent-held child wellbeing books [25,26] and used to provide access to
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), which outlines the importance of Indigenous
sovereignty of data. All requests for de-identified
individual participant data or study documents will
be considered, where the proposed use aligns with
the ethical approval for the study, aligns with
public-good purposes, does not conflict with other
requests, or planned use by the Study Steering
Committee, and the requestor is willing to sign a
data access agreement and has obtained relevant
ethical approvals. Contact will be via Director of the
National Institute for Health Innovation
enquires@nihi.auckland.ac.nz or the National
Ethics Advisory Committee neac@health.govt.nz.
Information for the See How They Grow app can be
found at the GitHub link, https://github.com/
SeeHowTheyGrow/SHTG_MobileApp.
Funding: This study was funded through a
contestable funding round by New Zealand Cure
Kids (https://curekids.org.nz/), the National Science
Challenge: a Better Start (https://www.abetterstart.
nz/) and Precision Driven Health (https://
precisiondrivenhealth.com/), grant reference 7006.
The funders had no influence on the design,
implementation, interpretation or reporting of the
study findings.
Competing interests: This study was funded
through a contestable funding round by Cure Kids
(https://curekids.org.nz/), the National Science
Challenge: a Better Start (https://www.abetterstart.
nz/) and Precision Driven Health (PDH) (https://
precisiondrivenhealth.com/), grant reference 7006.
PDH is a commercial entity. The funders including
PDH, had no influence on the design,
implementation, interpretation or reporting of the
study findings. The involvement of PDH, does not
alter our adherence to PLOS ONE policies on
sharing data and materials.
understandable, evidence-based information to parents about their child’s growth compared
to population norms [27]. Growth charts can play an important role in helping parents, at a
glance, view the growth of their child. Despite this, parental understanding of the meaning of
growth charts relative to their child(ren) is variable [28,29].
However, some health professionals report that they often don’t use these charts with
parents [30]. The reasons given include that parents have low health literacy [31]; parents find
growth charts confusing [32] and misunderstand the meaning of chart percentiles (including
the misperception that a high percentile is a sign of robustness), and confusion about popula-
tion norms and how that applies to their child [28,33–36]. Health professionals have also
reported that the hand-held record book is often forgotten or lost, reducing its value for
parents [37]. Notwithstanding this, parents do have a desire to hear if their child was at risk of
obesity [38].
The rapid growth in mobile technology and in particular, the ubiquity of the smartphone is
an opportunity to overcome such issues by digitising the hand-held growth record. A plethora
of child growth labelled apps are available on the App Stores. Yet little evidence exists of the
effectiveness of these apps in the prevention of childhood overweight and obesity [39].
Child health in the New Zealand context
Child health in New Zealand is packaged as a comprehensive programme called Well-Child/
Tamariki Ora. The Tamariki Ora/Well-Child programme is a comprehensive package of uni-
versal health services offered free to all New Zealand families/whānau for children from birth
to 5 years. There are 13 planned health check contacts, with 11 checks provided between birth
and 18-months. Several organisations specifically provide well-child services nationally, for
example, Plunket (https://www.plunket.org.nz/) while other organisations are location-specific
[40] or are Māori (indigenous population), providers. Services are provided by several health
professions including midwifery, obstetrics, paediatrics, general practitioners and registered
nurses. These services are often supported by kaiāwhina (community health workers) and
vision and hearing technicians [26] and delivered in a variety of settings such as primary care
settings, Marae (a place where for Māori communities gather and share) and the home. A Well
Child/Tamariki Ora Health book is also produced and is given to all parents of new babies, to
use as a hand-held record of health visits and immunisations. The Well Child / Tamariki Ora
Health book also includes information for parents on milestones, safety and illnesses [41].
In this study, we aimed to co-create a child growth monitoring app and test its utility and
feasibility. The focus on children from birth to two years was chosen because excessive weight
gain in the first 100 weeks of life may be an important marker for the onset of overweight by
school age and into adulthood [42,43], and because of the high number of planned and free
Well-Child/Tamariki Ora health visits in the first 24 months of life in New Zealand [26].
Study objectives
This study aimed to co-create, develop and test the utility and feasibility of a smartphone-
based digital child growth application (app) for use by New Zealand parents and caregivers
with children aged 0–24 months.
Methods
Co-creation and development of the app
Between January—May 2018, an iterative process was used to gather detailed requirements for
the app. This process involved a national on-line survey and focus groups of parents and/or
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caregivers with children under the age of 5 years, and interviews with health professionals
(midwife, paediatrician, nurses) working in child health services. Recruitment processes for
the survey used social media advertising (via FaceBook posts, Google Ads), using title tags
such as “well-child providers”, and meta description tags such as “childhood development
milestones.” Health provider and parent focus group participants were identified and invited
to participate through existing networks.
Informed consent was obtained from all participants. Parent participants were asked what
they knew about growth charts and the tools they used to help monitor their children’s growth.
Health professionals were asked how they used growth charts with parents and barriers to
their use. All participants were asked about what features and functions they would want in a
digital growth chart tool. The final app features and functions would be pragmatically deter-
mined based on study time-frames and the technical difficulty and time need to build a partic-
ular feature.
To accompany the app and provide positive framed content and activity related prompts,
within app notifications were used. App notifications are messages that display outside of the
app and are used to communicate information (support knowledge development) and
reminders (to act or do something) to the user. The type and content of the See How They
Grow app (SHTG) notifications were underpinned by behaviour change theory [44,45], and
mHealth engagement research [46]. A programme logic was used to determine the type and
frequency of these notifications.
In addition to routinely programmed information and activity notifications, specific action
notification messages about entering a measurement were sent at 3-days and 14-days if no
new measure had been added, and a third notification was sent if it was longer than 6-weeks
since the last data entry. If participants had entered a measurement, they would not receive
these message types.
The app was built for both Apple and Android operating systems using Ionic (https://
ionicframework.com) and was made available for download from February–August 2019.
Ethics approvals were obtained from the Auckland University Human Participants Ethics
Committee; Formative Study Reference 020166 and Feasibility Study Reference 022248. The
feasibility study was registered on the Australia New Zealand Clinical Trials Registry
(ANZCTR) reference ACTRN12619000905167.
Feasibility and utility assessment
Participants were eligible to take part in the study if they were, 1) adults aged 18-years and
over, 2) lived in NZ, 3) had a child or children under the age of 2-years, 4) had access and use
of a smartphone capable of downloading the app and 5) were able to read and understand
English. Eligible participants provided informed consent (agreement to complete a baseline
and 12-week follow-up questionnaire, to enter at least three measures during the 12-week
study period and for their app use data to be collected during and post-12-weeks (until the last
participant had completed 12-weeks). All study procedures and data collection were managed
through the app. Engagement with the app was measured using the date of last activity, fre-
quency of use and self-reported feedback on utility, barriers, enablers and improvements (see
Table 1). Underpinned by the broader app engagement literature, the engagement categories
were explicitly designed for this study. The app had both off-line and on-line capability.
Recruitment
Recruitment promotion strategies included inviting participants from the co-creation phase,
social media posts using keywords and meta tags such as “Māori well-child services”,
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“traditional Māori parenting” or child immunisations”; paid digital advertising, a study web-
site, promotion through health provider networks and hard-copy flyers placed in new baby
packs.
As a feasibility study, no sample size calculation was performed. All statistical analyses used
SAS™with descriptive statistics used to analyse participant characteristics, app engagement
and utilisation variables and Chi-square and Fisher Exact Tests used to compare differences.
We did not include invited users in these analyses due to the low numbers (n = 4). For analyses
participants were grouped into age bands (18–19; 20–24; 25–29; 30–34; 35–39; 40–44, and 45–
49).
Results
Co-creation and development of the See How They Grow app
One hundred and ten parents or caregivers responded to the requirements survey with 101
included in the final analyses. Nine participants were excluded as they provided no or limited
information. The majority were NZ European ethnic group with only 8% reporting as Māori.
Participants were between 20 and 39 years. Fifty-one per cent reported that their youngest
child was 12-months. Of the four focus groups, three comprised mainly of Māori and Pasi-
fika parents, while the fourth group was mainly composed of NZ European parents and care-
givers. Focus group numbers ranged from 5 to 8 participants. Most participants were women.
Face-to-face interviews involved two midwives, a well-child nurse educator and a paediatrician
and seven other well-child health providers provided email comments.
Table 1. Schedule of baseline and follow-up data collection.
Description Baseline 12-weeks
Eligibility ✓
E-informed consent ✓
Age, sex, and ethnicity of adult users ✓
Age and sex of the child ✓
Home Region ✓
Baseline Survey
•Demographics
•Knowledge of growth charts
•Use of growth charts
✓
Follow up Survey
•Reported changes in knowledge of growth charts
•Reported changes in activities
•Reported changes in foods offered
•Perception of usefulness and utility
•Barriers,enablers
•Best features
•Improvements
✓
App engagement
• Not engaged No activity beyond day 1
• Somewhat engaged No activity past 30 days
• Mostly Engaged No activity past 60 days
• Actively Engaged Activity throughout 90 days
• Very Engaged Activity post 90 days
✓
•Frequency of app use Continuous throughout the study
•Type of app use Continuous throughout the study
Feedback At any time throughout the app
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All parents or caregivers reported that knowing how their children were growing was
important. Discussions of their child’s growth needed to be grounded in the broader context
of their culture and social situation. The influence of culture was intricately woven into how
they, as parents make decisions about their child(ren). Therefore, any tool needs to have an
element of understanding about the norms, values, ideas and behaviours that may be deeply
rooted in a particular culture and form part of daily living, to be successful. Foods and activi-
ties that were culturally relevant, were suggested as simple ways to incorporate some cultural
nuances into the SHTG app.
However, when growth was discussed in the context of mapping measures onto growth
charts, focus group participants, and 72% (n = 73) of survey participants reported that they
thought the growth charts were more a tool for the health professional than for them.
Health professionals all reported they used growth charts with the parents or caregivers
they worked with, but that parental understanding of the purpose of growth charts was vari-
able. Most noted that it was common for parents to forget to bring their hand-held book to the
visit and consequently, the utility of the growth chart in the book was suboptimal due to a lack
of measures entered.
All participant groups (parent and health professional) remarked that an electronic tool
would be a useful addition to the well-child space. And that it was important that any digital
tool helped to reinforce New Zealand-oriented information and evidence, and supported the
relationships between parents and well-child providers and other health professionals, rather
than be perceived as replacing them.
Parent or caregivers reported that they should be able to add their self-collected measures
onto a digital chart. This capability elicited a cautionary reaction from the health professional
participants, as they were concerned that parents might become obsessive about growth indi-
cators as a singular measure of wellbeing. They also remarked that it would be important to
convey that a self-measurement was different from one performed and recorded by a health
professional and not confuse interpretations.
Three main themes emerged to describe barriers to digital tool use,
1. Functional (such as internet access, access to smart devices),
2. Acceptability and Utility (such as information relevancy, ease of use and cultural relevancy),
and
3. Systems (e.g. privacy and security, information ownership).
Determining and shaping the features and functions to include in the See
How They Grow app
Identified functions and features were converted into use-case stories, and these were mapped
to underpinning conceptual knowledge and behavioural change themes. Table 2 presents the
findings from this process, and Fig 1 provides a snapshot of images from the final SHTG app
design. There were over 50 screens with which the participant could navigate and interact.
Tables 3and 4present a sample of the notification message types sent to participants. The
words in brackets such as [HI] or [FIRSTNAME] are tokens, and they are used to personalise
the message. For example, the participant registered their First Name as Moana and ethnicity
as Māori; therefore, the bracketed words would be replaced with Kia or Moana.
Feasibility study
A total of 225 people from across NZ downloaded the app. Of these, 17 (7.5%) were excluded as no
data were entered, and 208 (92.4%) participants were eligible. Of the eligible participants, eight (4%)
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registered two children, while all others registered one child. Of the 208 eligible participants, 101
(49.5%) completed the follow-up survey (Table 5). The majority of participants (191, 92%) reported
that they were female (P = 0.008) and the mother of the child (193, 93%); were mostly European
(78%). Māori participants were significantly less likely to complete the follow-up survey (baseline
14% were Maori, Follow-up 8%: p = 0.010). There was no difference in participants by age at base-
line and follow up were similar (p0.227). At baseline, the mean child age was 7.8 months (median
5.7 months, SD 6.4 months). There were more participants with children aged 6-months com-
pleting the follow-up survey compared with those aged 6-months (p0.001).
Measurement data entered
Almost half (100; 48%) entered measures (weight, height, head circumference) on three occa-
sions or more, with 25% (n = 52) adding two measurements. Weight and height were the most
Table 2. See How They Grow app design features and functions.
Key Features Identified Purpose/ Intent of
Features and Behaviour
Change
Conceptual
Themes
Use Case Examples Final Features and Functions adopted in
See How They Grow
“Ability to upload photos.”To share experiences,
memories and have
reinforcement (BCT 3.1)
TRUST /
INTEGRITY
• To be able to add my comments or photos
and have others (privately or publicly) view
and comment so that it is more than just
measures.
• Create a longitudinal experience or history
makes it difficult to stop interacting and
difficult to delete, so I keep using it, and it is
useful.
• Invite Others,
• Create Memories,
• Share Memories,
• Enable others to like/comment on
memories
• Add photos
“Share experiences.”SOCIAL /
CULTURAL
/BELIEFS
“Share growth.”
“Positive quotes/
comments—sometimes new
mums just need to hear they
are doing a good job!”
To be rewarded, receive
feedback, feel positive
(BCT 10.3)
INDEPENDENCE /
EMPOWERMENT
• To add or interact within the app and
receive “unanticipated” rewards or
appreciation that help reinforce behaviour
• Having information in smaller sections
and showing easy actions to promote a sense
of capability and then skill development
linked to my child(ren) age and stage of
development
• Messages (notifications) that pop-up when
you complete an activity in the app such as a
child’s measure or tick an immunisation
with a positive message
• Informative and timely messages
(notifications)
• Likes and comments on Memories Page
• Action prompts regarding measurements
are about seeing a pattern and learning
from each step, so if a change is considered
important, then it seems more achievable.
EMOTIONAL
“Clearer indication of what
weight is healthy (e.g.
percentile range) at what
age.”
Supports changes (BCT
2.2) Investment
APPLICABLE
KNOWLEDGE
• Real-time notification messages to
reinforce activities and help to interpret or
reinforce the activity
• To have new or novel information
presented either through news type feeds or
notifications or links out if needed to read
more.
• Attracting the attention of the user is about
relevance and supports the usefulness of the
app
• Supports idea for how to change
• Managing their child measures
• Map measurements to their child and
present back what that measure means.
• Additional measurements entered
prompts new information notifications
• Resources and Tips sections,
“See change and understand
it.” “Child first aid.”
New information and
interpretation
ACTION
“Tips around keeping your
child healthy.”
Attention-grabbing
“Family support and
“Family groups can be
created.”
“Self-entered data on other
things.”
“Reminders for important
events.”
Personalise SKILLS /
MANAGING RISK
• Being able to see data in a way that is
relevant to me and minimises unhelpful/
inappropriate comparisons
• Creates achievements and motivations to
keep me engaged
• Integrated with my own calendar,
reminders of important events/activities like
immunisations, so I have it all in one place.
• Can add other information important to
me and my child(ren), like feeds or nappy
change or sleep.
• Select avatars or add photos self and
children.
• Ability to create a whanau group to share
the child(ren) journey and information
• Calendar links to immunisation timelines.
• Event entry within the app that links to
the phone “native” calendar to minimise
duplication and create synergy with
common phone activity.
Interpretation and
relevancy
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frequently entered of all measure types (70% and 66% respectively). Ninety per cent of all mea-
surements were recorded as being from a Health Professional with 70% of these being for
children 6-months.
Fig 1. Images of some of the elements of the See How They Grow app.
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Engagement
Date of last activity. Five categories from not engaged (no activity after day one) to very
engaged (activity ongoing after 12-weeks) were used to categorise participant app use data.
Forty-four per cent (n = 91/208) of baseline participants were engaged up to or over the
12-weeks. This group were more likely to complete the 12-week survey. There were no differ-
ences in the ages of participants and their last activity (Chi-squared p = 0.494). However, par-
ticipants who identified as Māori were more likely to have no app activity recorded after 60
days (Fisher Exact Test p = 0.017) compared to Non-Māori (Table 6).
Navigation and exploring screens. We found no difference in the number of screens nav-
igated to and viewed, irrespective of when the last app activity was (see Table 7).
The role of notifications in supporting app activity and engagement. Measurements
entered after a reminder notification was received, are presented in Fig 2. The day three
reminders were sent to 87 participants prompting 42 new measurements entered on the same
day or the next. The day 14 reminder was sent to 76 participants, and 24 new measurements
were added. The week six reminder was sent to 65 participants, and 28 new measurements
were entered.
Table 3. Examples of the routine within app notifications.
Routine messages
using programme logic
Message Type Timing
(day)
Message content
Welcome 0 Welcome to the SHTG study. Over the next 3-months, you will be part of a
study designed to test out our new app. Thank you for taking part.
Welcome #2 regarding study contact details 2 [HI] [FIRSTNAME], thanks for taking part in the SHTG study. If you need to
contact us, you can call us on 0800 3676444 or email us on
seehowtheygrow@auckland.ac.nz
Reminder about app functions–Resources 5 We hope you are enjoying the SHTG app. Did you know that the app has
information about services and events relevant to your child as well as tips to
support your child’s healthy growth?
Reminder about app functions—
immunisations & re flagging immunisations
complete in the app
9 Has [CHILDNAME] had [HIS/HER] latest immunisations? If so, you can
update this in the app. Go to immunisations and tick the ones [HE/SHE] has
had.
About growth tracking 10 Remember, a growth chart isn’t a test that children can pass or fail, and there
isn’t a centile that he or she must reach to be healthy.
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Table 4. Examples of data entry dependent messages.
Data Entry
Dependant Messages
Examples
Message Description Message content Mapped to
Conceptual
Themes
First measure entered after registration Thanks for entering in a weight measurement for [CHILDNAME].
It looks like [HE/SHE] is in the [CENTILE#] centile for weight.
APPLICABLE
KNOWLEDGE
New measurement entered by professional Thanks for entering in a new weight measurement for
[CHILDNAME]. It looks like [HE/SHE] is continuing to grow along
the same centile for weight which is great.
APPLICABLE
KNOWLEDGE
SKILLS
Decrease in weight (across one centile band)
compared with the previous measure–Non-
professional gathered measure
Thanks for entering in a new weight measurement for
[CHILDNAME]. It looks like the rate that [HE/SHE] is growing
might have decreased. This is usually ok, but it is a good idea to talk
to your doctor or nurse if you are concerned. Also, look at TIPS
for more information on centiles.
APPLICABLE
KNOWLEDGE
ACTION
SKILLS
Message if there is a change across once centile
bands up or down.
[HI], you can expect to see [CHILDNAME] growth line stay roughly
in the same area of the chart as [HE/SHE] grows, but it probably
won’t follow a centile line exactly. It’s perfectly normal for [HIS/
HER] growth line to move between centiles occasionally.
APPLICABLE
KNOWLEDGE
SKILLS
MANAGING RISK
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Improved growth chart interpretation and understanding
At baseline, the majority of participants responded that they were aware of the Well Child
Tamariki Ora book (201; 97%) and 96% (192) reported finding them useful for tracking their
Table 5. Characteristics of participants at baseline and follow-up.
Baseline 12-week Follow up Survey
Completed
N % N % Chisq p
Total 208 - 101 -
Relationship to child
Father 13 6 4 4
Friend 1 0 0
Mother 193 93 98 95
Uncle 1 0 1 1
Ethnicity (note more than one can be selected)
European 163 78 84 82 0.337
Maori 30 14 8 8 0.010
Asian 7 3 5 5
Pacific 11 5 4 4
Chinese 6 3 5 5
Indian 9 4 3 3
Other 16 8 8 8
Gender 0.008
Female 191 92 98 95
Male 17 8 5 5
Collapsed Age Groups 0.227
18–19 3 1 2 2
20–24 16 8 9 9
25–29 53 25 25 24
30–34 65 31 38 37
35–39 61 29 26 25
40–44 9 4 3 3
45–49 1 0 0
Region
Auckland 97 47 52 50
Bay of Plenty 13 6 8 8
Canterbury 13 6 8 8
Hawke’s Bay 3 1 2 2
Manawatu-Wanganui 6 3 3 3
Northland 21 10 8 8
Otago 4 2 1 1
Southland 2 1 0
Taranaki 2 1 2 2
Tasman 1 0 1 1
Waikato 21 10 5 5
Wellington 23 11 12 12
West Coast 2 1 1 1
Chi-squared P value comparing participants that completed the follow-up survey to those that didn’t.
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child’s growth. One-third reported that they understood the information conveyed by growth
charts only "a little" (68, 34%) while 65% (130) reported understanding them clearly and 1%
reporting not understanding them at all. The majority of participants (173; 86%) reported that
the growth charts were relevant to their child. Of the 101 (48.5%) participants who completed
the 12-week survey, 72 (70%) agreed that the app helped them to understand and interpret
growth charts better. All except one participant reported that they found that the visual presen-
tation and the interpretive information provided after measurements were entered were infor-
mative and relevant to their child. The following quotes illustrate how some participants found
the app useful:
It gives the caregiver a visual representation to see how their child is growing, and it sends use-
ful notifications.
Parent of under 6-month child
Because we could show the GP + the paediatrician when we had to see them.The DHB [Dis-
trict Health Board] Paediatrician had paper and had to replicate the plots,and the GP only
entered the measurement she took,which didn’t show a trend.We had the birth weight,plun-
ket weights,nurse weights,paediatrician AND GP weights on the graph.
Parent of under 6-month child
Four participants reported that they did not find SHTG useful overall. "Potential privacy
issues" was the only free-text comment documented to explain this response.
Twenty-one per cent (22) reported that they had learnt something new at the end of the
12-week study. Of these, 19 were 34-years of age, and 17 had children 6-months of age,
Table 6. Participant last app activity by engagement category.
Baseline 12-week Follow-up
N % N %
Engagement Categories Total 208 - 101
1 Not engaged No activity beyond day 1 48 23 8 8
2 Somewhat engaged No activity past 30 days 38 18 6 6
3 Mostly Engaged No activity past 60 days 31 15 15 15
4 Actively Engaged Activity up to 90 days 25 12 17 17
5 Very Engaged Activity past 90 days 66 32 55 54
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Table 7. The number of screen views by last activity engagement categories.
Screen Views
Engagement Category N (%) mean sd median lower IQRupper IQRmin max
1 Not engaged No activity beyond day 1 48 (23) 22.3 12.7 20 12 34 2 47
2 Somewhat engaged No activity past 30 days 38 (18) 32 32.5 23.5 17.5 30.5 13 141
3 Mostly Engaged No activity past 60 days 31 (15) 22.8 22.6 15 8 34.5 2 90
4 Actively Engaged Activity up to 90 days 25 (12) 14.1 8.9 13 9 17 1 41
5 Very Engaged Activity past 90 days 66 (32) 33.5 29.6 28 15 41 2 138
Interquartile range
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with the majority of responses being from European ethnicity (18). Box 1 presents the main
themes where participants reported gaining new knowledge or understanding.
Food and activity knowledge and behaviour changes
There were 81 eligible participants after excluding responses from parents who signalled that
they were still exclusively breastfeeding (17/101) and those that did not respond to this
Fig 2. Notifications and corresponding app activity.
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Box 1. What was something new that I learnt while using the SHTG
app?
Knowledge Related to their Child Understanding
Centiles
General Knowledge of Growth Charts
• How well they are growing (hopefully)
and when to be concerned
• I read extra about growth charts to feel
better than my child was dropping
percentile points. I spoke with my Plunket
nurse who reassured me that my child’s
growth, while not following the line, was
still tracking very well
• If my son is on average growth.
• That it’s not a test that a child must pass.
Each child is different and they don’t have
to be a certain centile to be healthy
• That a general consistent growth is
healthy! And I would imagine it would be
really good to notice weight loss due to
illness or allergy
• It was interesting to see where his
different measurements sat on the
percentile
• When to be concerned & contact a health
professional
• That so long as your child follows their
own line and keeps making progress they
are on the right track
• What the
percentiles meant
• Differences in
percentiles
• How the
percentiles work
• Why they are
relevant
• The way
percentiles work
• How Plunket nurses use a growth chart
• That it’s an accumulation of the data set/
trend of growth that matters not a single
point that really matters.
• That they just have to follow one line not
try to get to 100%
• That growth charts include height and
head as well as weight
• The data used to formulate the growth
charts
• I really liked the blub below the chart
explaining that all babies grow differently
etc
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question (3). Of these 81 participants, the majority (71) reported: "No—SHTG did not change
what foods they provided," whereas 10 participants reported either "yes" (n = 6) or "a little"
(n = 4) to making a change to the foods they offered. “Offered more variety”, “amount of food
offered”, and “new ideas of what to offer” were the typical responses.
Eleven participants reported "yes" (n = 8) or "a little" (n = 3) to increasing the activities they
and their child were doing. The remaining participants either did not answer this question
(n = 13) or reported No (n = 77). "More tummy time" and "more playtime" were the common
free-text responses with one participant remarking that SHTG "Helped me figure out more sim-
ple yet effective activities to do with my baby".
Other features and functions used
Sharing the app was highlighted as an important feature in the co-creation phase, and 41
(20%) participants sent a share app invitation. All were parents or caregivers of children aged
under 12-months. Being the Partner of the invitee, was the main category for whom was
invited (n = 17), followed by Grandparents (n = 3), Sisters/Brothers, Aunties/Uncles, extended
whānau/family and Other, were all equally mentioned (n = 2 respectively). Only three people
accepted the invitation. Despite the low use of this feature, 74% (n = 76) of survey respondents,
reported that this is an important feature.
Adding self-measurements and reported positively by 95%, followed by the resources and tips
screens (40%). The link to services and activities and adding photos were the third and fourth liked
features, 17% and 12% respectively. Interestingly, 23% liked the notification messages while almost
the same proportion (25%) did not. This latter group were more likely to have their last activity
recorded at 0–30 days, whereas the former group were actively using the app for the full 12-weeks.
Technical issues
Sixty-two per cent of participants (n = 64) reported that they had no technical problems with
the app. Not being able to delete a measure or zoom in on the charts were reported as prob-
lems, albeit these capabilities had not been designed into the app.
Acceptability feedback and new features
The majority of participants (87%; 88) reported that they would recommend the app to others. One
hundred participants (97%) said that the app was culturally appropriate and that the role of culture
needed to be woven into the information provided, as illustrated in the following response.
There are lots of cultural difference for Chinese mums during the first month after the birth of
baby, including food, diet, beliefs.
Parent of under 6-month child
The majority (86%, 87) recommended that the app should include monitoring for children
over 24-months old.
While participant comments overall were positive, some participants (7) did not find the
app useful, appealing or easy to use for example one participant’s remarked,
The app is just a bit clunky to use. If it was easier to operate or automatically updated, then
the app would be awesome!
Parent with a 6-12-month child.
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A range of suggestions for new features and general app improvements are illustrated in
Box 2.
Finally, the importance of being able to share the information with a family doctor or health
provider was highlighted, with one participant commenting on the importance of this feature
for them.
Ability to email to GP [General Practitioner], so the export says where the data is from and
its provenance.I had to explain to the GP who had entered the data incorrectly into her Med-
Tech chart,and said ’growth looks normal’ THEN I showed her the app and my growth chart
and then my interpretation and she suddenly realised she’d inputted her data incorrectly.
Parent with a 6-12-month child.
Discussion
The findings from this feasibility study highlight that the digitalisation of growth charts and
embedding these within a mobile app is an acceptable and potentially preferable modality for
parents and carers to capture and monitor their child’s growth. This finding was most appar-
ent amongst parents with children under 6- months. While not a panacea, increasingly
research is finding that a variety of interventions in the prenatal and early infancy period.
Findings reported were improvement in positive parental health practises, such as longer
breastfeeding, later introduction of solids and increased child activity, all having a positive
impact on early obesity compared to control groups [23].
The lower engagement by Māori compared to non-Māori suggests that SHTG was missing
something that could have kept this cohort engaged longer. The role of culture in child-rearing
and perceptions of growth and development needs to be better understood and interventions
designed that account for these differences, otherwise, it is likely they could increase the dis-
parity [47–49].
The majority of app activity was related to entering measures. When measures were
entered, the data were overwhelmingly labelled as being from health professionals; reinforcing
the importance parents placed on this trusted information. Importantly, we found knowledge
and understanding of growth measures increased over the study period. Still, the impact for
Māori was muted due to the lower SHTG engagement over time, similarly for Pasifika popula-
tions who were under-represented as participants overall; despite these groups being well rep-
resented in the co-creation phase. Future research which includes interviews or focus groups
with participants at the end of these feasibility studies, would help provide more contextualisa-
tion and understanding of the usage data than survey tools can.
The impact of personalised and tailored messages have been well researched for text mes-
saging interventions [49–51]. Similar in principle to text messaging are app notification
Box 2. New features and functions
•Having tick boxes for when immunisations are completed.
•Being able to zoom into the graphs.
•Having multimedia options such as videos on what to expect at milestones.
•Being able to delete incorrect entries easier.
•Feed and sleep tracking.
•More ideas for activities.
•Have more information on how to stimulate motor development and cognitive abilities.
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messages. The added advantage of app notification messages is that they can also guide the
end-user to further information within the app or to record an activity. While text messaging
can also direct users to further information, it is difficult to measure unless participants
actively report their behaviour. With app notifications, measuring responses is much simpler,
as the receipt of the notification and response can be captured and counted. We found that for
some, the notification feature was annoying, but some notifications did trigger the corre-
sponding activity suggesting that they can be useful tools to engage end-users. Other studies
have found similar outcomes, for example, Freyne et al. [52] report in their study on partial
meal replacement that participants with access to self-monitoring tools and notifications
accessed the app more than those with program information only. They also report that activ-
ity in the app was almost double around the time(s) notifications were sent compared to other
times.
There was no notable impact on any behaviour changes regarding nutrition or activity by
participants that may have been influenced by using the app. However, the positive direction
of notification and action suggests that further development of the app to include a compre-
hensive adaptive and responsive element underpinned by theory could influence both knowl-
edge and behaviour.
Further understanding of the reasons for family or friends not accepting invites to use the
app, is needed. The main areas for improvement were minor functional improvements and
some feature enhancements suggesting that the co-creation phase had identified many of the
desirable features and functions. Furthermore, the additional features suggested were not
unexpected, for example, to expand it to encompass a more extensive age range, at minimum
0–5 five-year-olds, and to have more interactive elements and tailored age-appropriate multi-
media tools. These latter two attributes are commonly available in more commercially avail-
able applications (for example in travel and banking mobile applications).
The low Māori and Pasifika engagement suggests that exploring the cultural aspects and
contextual understandings of parenting are essential to ensure that the final product supports
and encourages engagement beyond the first few interactions.
Overall, the SHTG feasibility study found that a digital growth chart and mHealth interven-
tion has the potential to be acceptable and useful for supporting parents in their knowledge of
growth charts and by encouraging them to actively monitor their child’s growth. This finding
aligns with other results that have used digital tools in the prevention of obesity in older chil-
dren. While not specific to the use of growth charts, a systematic review of studies using wire-
less and mobile technologies to prevent and treat paediatric obesity, report that several of the
studies included in the review describe increases in physical activity, increased fruit and vege-
table intake and improved self-monitoring [39].
Conclusion
The See How They Grow app was found to be acceptable, feasible and easy to use by the major-
ity of the participants. While this study was not powered to detect changes or to measure the
impact of the app on knowledge and behaviour change, the findings suggest that further devel-
opment is worth pursuing. Despite high participation in the co-creation phase, the low uptake
of indigenous and Pasifika populations is a notable limitation to the findings. Critical next
steps will be to include more depth, culturally appropriate and relevant content to meet the
diverse needs of all population groups. Similarly, understanding the reasons for the higher dis-
engagement amongst some population groups is also needed. This should be followed by more
research that explores the impact of digital growth and mHealth tools on reducing childhood
overweight and obesity.
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Supporting information
S1 File.
(PDF)
Acknowledgments
The authors would like to thank the parents and health professionals who participated in the
co-creation and development study and helped shape the app, as well as the parents who took
part. We also wish to thank the project and the technical team.
Author Contributions
Conceptualization: Gayl Humphrey, Chris Bullen.
Formal analysis: Gayl Humphrey, Varsha Parag.
Funding acquisition: Gayl Humphrey, Chris Bullen.
Investigation: Marion Hiemstra.
Methodology: Gayl Humphrey, Rosie Dobson, Stephen Howie, Samantha Marsh, Susan Mor-
ton, Dylan Mordaunt, Chris Bullen.
Project administration: Angela Wadham.
Supervision: Gayl Humphrey.
Validation: Gayl Humphrey, Varsha Parag.
Visualization: Gayl Humphrey, Samantha Marsh.
Writing – original draft: Gayl Humphrey.
Writing – review & editing: Gayl Humphrey, Rosie Dobson, Varsha Parag, Marion Hiemstra,
Stephen Howie, Samantha Marsh, Susan Morton, Dylan Mordaunt, Chris Bullen.
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