In the Netherlands, 6.9 % of the children are born prematurely (before 37 weeks of gestational age) [1]. Although advances in perinatal and neonatal care have significantly improved survival rates for preterm infants [2], preterm birth still accounts for 66% of all deaths occurring before or during the first month after birth [3]. Prematurity also has large adverse effects on children’s motor, cognitive, and socioemotional development [4]. Giving birth to a premature infant is also a disruptive start for parents [5]. Parents of preterm infants often experience a range of mental health problems, such as anxiety and depression [6]. The dependency on medical and health professionals can challenge the formation of a secure infant-parent relationship and parents’ self-efficacy in their ability to independently care for their infant [7]. The transition to home following discharge is known as challenging. Without the 24/7 access to health care professionals, parents of preterm infants feel unprepared for this new situation and lack confidence in their capacity to care for their infant [8]. Despite efforts to improve parents’ readiness for discharge and the availability of follow-up services, many parents of preterm infants continue to experience unmet needs for support and practical information after leaving the hospital [9,10]. As the infant’s care needs and developmental milestones evolve during the first year, the informational needs of parents of preterm infants also shift accordingly. Providing tailored information about the consequences of prematurity and the specific health, behavioral, and developmental needs of premature infants can strengthen parental self-efficacy, enhance their sense of security in caring for their infant, and potentially reduce health care use [11,12].

After returning home, parents of preterm infants search the internet for information on topics, such as infant crying, choice of formula, common illnesses, and developmental stages. While they use search engines, social media, or mobile health (mHealth) apps, finding appropriate and reliable information on the unique challenges of caring for a preterm infant at home remains difficult [8,9]. The use of mHealth could support a shift from time- and professional-dependent access to information toward a more autonomous approach, empowering parents to obtain information whenever and wherever they need it. However, for mHealth apps to be useful and effective, they must address the specific information needs of parents of preterm infants [13,14]. In addition, the app must be user-friendly [15] and the information accessible and easy to understand for parents across varying levels of education and health literacy [16].

mHealth education interventions for parents of premature infants were developed over the last decades. However, Richardson’s evaluation of mobile apps targeting parents of infants in the neonatal intensive care unit (NICU) revealed that many apps are lacking quality and credibility or do not contain content identified by parents as important [17]. In contrast, the study on the NICU2HOME app provides high-quality information on infant and self-care during and after the NICU stay and showed promising results in enhancing parental self-efficacy and discharge preparedness [18]. Despite the rich body of literature regarding parental needs for information after discharge, available apps targeting the postdischarge period are limited. A systematic app review of mobile information apps for parents of preterm infants after hospital discharge found that, while the overall quality of the identified apps was acceptable, they insufficiently addressed key postdischarge concerns, such as information on transitions in nutrition, sleep patterns, or developmental stages [19]. This lack of targeted content may contribute to the limited usage and adoption of these apps, a common pitfall when end users and stakeholders are not adequately involved in the design process [20]. Participatory design approaches, such as the design thinking method, ensure that user requirements are accurately captured from the perspective of the end users, thereby enhancing usability and facilitating effective implementation [21-24].

In the Netherlands, a 1-year home-based responsive parenting intervention (TOP program) is standard care for very preterm infants and their parents and is currently expanded for moderate to late preterm infants. Pediatric physical therapists with an additional 1-year TOP training and affiliated with the Dutch Expertise Center for Premature Infants (EOP) carry out the TOP program. The strength-based and process-oriented intervention consists of 7 key strategies to enhance parental understanding of the infants’ behavioral and developmental needs [25]. An important key strategy is to provide parents with information about their infant’s behavioral and developmental needs. To enhance parents’ knowledge and understanding of their infants’ needs, TOP interventionists provide verbal information transfer and an individualized written parental report with strength-based recommendations accompanied by photos taken during the home visit. Despite the benefits of face-to-face care, there is a need for a complementary mHealth intervention that enhances information retention, supports parental confidence in managing their infant’s care, and potentially reduces their reliance on health care professionals [9,14]. Therefore, we aim to complement and enhance the existing Dutch TOP program by addressing gaps in information retention and supporting professionals in delivering reliable information to parents. Before conducting more extensive research to measure its effectiveness, developing an information app that ensures that user requirements are effectively incorporated and is tailored to the specific needs of parents of preterm infants is crucial.

The aim of this study was two-fold: (1) to develop a postdischarge information app (e-TOP) for parents of premature infants and (2) to evaluate its usability.

Questionnaire data were collected using the Castor database (Electronic Data Capture, Ciwit BV, 2021). Descriptive statistics were used to describe the participants and the user data (installs, visits, visit duration and change of usage over time, and visited topics). Questionnaire data were checked for normal distributions using a graphical summary of data and descriptive statistics. The median score with IQR was used in case of skewed distributions.

For the qualitative data collected through thinking aloud sessions and interviews, a pragmatic thematic analysis approach was used [37]. For the thinking aloud analysis, initial open coding was analyzed and discussed within the project group and subsequently categorized into themes. Subthemes were then developed under each main theme to capture more specific insights. In addition, user comments and open questions from the questionnaires were evaluated and categorized by the first author (MF). Ultimately, the qualitative analysis resulted in 4 overarching themes: user experience, content, navigation, and functionality.

A total of 55 participants completed the SUS, yielding a median total SUS score of 75.0 (IQR 67.5‐80.0), indicating generally good usability. The app was rated positively for its ease of use, functional integration, and user confidence.

Participants gave the app an overall satisfaction of 7.0 (IQR 7.0‐8.0), on a scale of 1‐10. Content satisfaction was rated with a mean score of 3.7 (SD 0.89) and the app’s appearance was considered attractive, with a mean score of 3.6 (SD 0.83) on a scale from 1 to 5. Participants found the pictures and videos particularly helpful (mean 4.0, SD 0.56) and expressed that the app was helpful in addition to face-to-face care from the TOP interventionist (mean 3.5, SD 0.99).

Data collected through thinking aloud sessions, interviews, and written comments from the app’s comment box were categorized in 4 themes: user experience, content, navigation, and functionality (see Table 4).

Participants appreciated the specificity and depth of information provided yet expressed concerns about retrieving tailored answers to specific situations. As a participant in the interview stated, “The only thing I couldn’t find was whether it’s possible to swim with a premature baby and at what age that is safe”. The app facilitated users’ understanding of infant behavioral cues and sleep patterns. However, parents also preferred direct interaction with a TOP interventionist, indicating a desire for more personalized and human support. For example, a mother stated in the interview that “The TOP interventionist explained it to me personally, so I found that easier and more comfortable.” Suggestions were given to incorporate interactive features, such as chat support or a parent community, indicating a preference for increased interactivity and social connection within the app.

The content was generally deemed useful and relevant to the specific needs of parents with premature infants. As 1 participant noted in the comment box, “It gives information you cannot find on the internet, all content is related to premature birth.” Suggestions for improvement emerged from both the interviews and the comment box. Requests for additional practical tips, along with more in-depth information on motor development and health-related concerns, highlighted opportunities to expand the scope of information. As a participant stated during the interview: “More information about motor development, like crawling, creeping, and sitting, would be helpful.” Another parent expressed during the interview, "I would like there to be more concrete information, such as a chart with a baby weighing this much should drink this much.” Videos were highlighted as particularly effective for conveying complex concepts, such as sleep patterns and infant signals.

While users found the landing pages clear and well-organized, they reported difficulties with lengthy chapters and locating specific information. As a participant during the interview reported: “Searching for specific information is more difficult if you don’t know under which chapter to search.” Another participant reported in the comment box: “The sub-chapters contain too much information and not so easy to find answers to your questions.” The need for enhanced navigation design, such as the inclusion of a search function, a home button, and scroll arrows, was suggested and could enhance information retrieval. A participant explained during the thinking aloud session: "If there was an arrow next to the app indicating that there’s more room to scroll down, you might have looked further.”

A timeline-based structure reflecting the developmental stages of premature infants was suggested as a potential solution to improve content organization. One participant stated in the comment box: “It would also be helpful if there was a timeline showing what a child should do at each (corrected) age.” The ability to share information easily with family members, particularly regarding hygiene practices for visits, emerged as a key functional improvement.

This study aimed to develop and evaluate a digital information source (e-TOP) to address the specific information needs of parents caring for preterm infants during the first year postdischarge.

To develop the e-TOP app, a user-centered design approach was used. The feedback from the 3 focus groups with TOP interventionists and parents of premature infants, including parents with LHL, directly influenced the app’s content and design. The cocreation and iterative process between experts, the design company, and the research team was highly successful in shaping the app’s functionality and refining its design and content. This collaborative approach ensured that the final prototype of the e-TOP app was both user-friendly and rich in relevant, evidence-based information, tailored to meet the diverse needs of its users. This methodology aligns with established practices in mHealth app development, emphasizing the importance of participatory design including health professionals to meet user needs [21-24].

Parents with LHL were actively engaged during the focus group meetings in the developmental phase of the e-TOP app. They expressed a need for clear, actionable information, preferably content in multiple formats, with an accessible tone and simplified messages. The app therefore incorporated features, such as simplified language (Level 1), multimedia content, and “read-out-loud” functionality to accommodate parents with LHL, with videos and text at different reading levels. This preference is supported by research indicating that visual-based interventions, particularly videos, are effective in improving health literacy and comprehension of health-related information [38].

Participants engaged with the app for a median total of 39 minutes (IQR 8.8-53.0) during the 6-month study period. The number of recorded actions per participant had a median of 64.0 (IQR 33.5-88.0), but usage varied significantly between participants. Differences in purpose, target groups, and the lack of user engagement metrics make comparison to other parenting apps challenging, as also described in Li’s systematic review of commercial mHealth parenting apps [39]. The e-TOP app is designed as an additional information source; if we compare the results to educational health apps, longer but less frequent sessions are found [40]. This found gap calls for established standardized benchmarks for digital engagement in neonatal mHealth interventions.

While the app was perceived as useful for finding information on prematurity-specific topics, user data revealed a decline in engagement after the initial 2 weeks. These differences in intent to use versus lower nonusage attrition are found in other web-based parenting interventions [15]. The e-TOP engagement peaked at week 11 and week 16. Parents revisited the app at key developmental milestones, such as rolling over, reaching for toys, and the transition to solid foods. Integrating features such as search functionality, interactive (push notifications and chat function), and timeline-based navigation could enhance the e-TOP app’s long-term utility [41,42].

SUS distribution with a mean SUS score of 68 is considered a suitable usability for Digital Health apps [43]. The e-TOP app demonstrated acceptable-to-good usability with a SUS score of 75.0 (IQR 67.5-80.0). By complementing the SUS with a customized satisfaction survey and data collected through thinking-aloud sessions, interviews, and written comments from the app’s comment box, this study followed best practices of combining quantitative ratings with rich qualitative findings for the usability testing [30]. Participants provided actionable feedback across key areas. By integrating these improvements, the e-TOP app can enhance usability, ensuring it remains a valuable long-term resource for parents of preterm infants.

The total study period of 2 years and restricted finances necessitated pragmatic approaches to the evaluation of the usability. We used several qualitative and quantitative methods, but we had to make compromises impacting the study methodology, such as the reliance on a single author for qualitative data analysis which may introduce bias. Integrating multiple researchers into the thematic analysis process not only enriches the analysis through diverse perspectives but also enhances the credibility and trustworthiness of the research findings [44].

Although parents with LHL contributed to the development of the app, the study faced challenges in recruiting parents with LHL for the evaluation phase. Their limited representation in the evaluation phase underscores a broader challenge in engaging these parents in research [45]. Barriers such as complex consent processes and digital questionnaires have hindered participation in our study. Allowing parents to first establish a connection with the researchers or interventionists and using postponed consent is expected to promote inclusivity. Also, verbal consent or simplified forms could foster inclusivity. Although improved comprehension and trust may have positive effects on study enrollment, we emphasize the active involvement of the target group in the early stages of research projects when developing the study design, procedures, and the selection of measurements [46].

This study had a high attrition of the fathers; only 32% of the fathers used the app and 25% completed the usability questionnaires. In general, retaining participants in studies using mHealth apps has been described as challenging [47]. The finding of higher attrition among fathers aligns with the results of the study on the NICU2HOME app (Garfield [18]), in which high usability scores were similarly observed among mothers, but lower engagement among fathers was noted [10]. Xie [48] also found in her systematic review of digital interventions for fathers of infants from conception to 12 months postpartum that fathers have expressed the need and desire for access to relevant, accurate, and up-to-date information on infant care and challenges associated with new parenthood and called for interventions that target father-identified priorities [49]. These studies and our findings highlight the importance of gaining a deeper understanding of perceived barriers to engaging fathers.

The usability evaluation confirms that the app was responsive to the needs of parents with a premature infant. Given the evidence supporting user-centered iterative development, we strongly advocate for proceeding with the implementation of the e-TOP app, ensuring it remains a valuable and available resource while integrating continuous user feedback by using real-time analytics, for example, engagement metrics [50,51]. Future research should focus on assessing the effectiveness by evaluating how app usage translates into improved parental confidence and decision-making in caregiving with the goal of reducing dependency on health care professionals and fostering parental autonomy.

The e-TOP app has demonstrated strong potential to complement information transfer to the face-to-face care after discharge and to bridge the information gap for parents when they leave the hospital. While usability findings are promising, continued development, customization, and integration of the app with health care systems are necessary to maximize its long-term impact. By addressing user engagement, content expansion, accessibility, and health care integration, future versions of e-TOP can become an essential tool for empowering parents of preterm infants and improving neonatal postdischarge care.