With the advent of the information age, the use of smartphones and apps is becoming more common. It is predicted that the world’s smartphone ownership rate will reach 66% in 2018, and China will have 1.3 billion smartphone users [1]. Meanwhile, the number of global app downloads has exceeded to 175 billion in 2017, with China becoming the world’s largest smartphone app market. In the 4^th quarter of 2017 alone, the usage time of Chinese users of iOS, Google Play, and third-party Android apps reached 200 billion hours [2]. China’s huge smartphone user base and high accessibility of Wi-Fi or 4G have made people’s frequent use of mobile apps a reality, and the use of these apps in health care is worthy of attention. As of December 2016, the number of people using the Internet for health purposes in China reached 195 million, accounting for 26.6% of all Internet users. Among them, the medical information inquiry use rate was the highest, accounting for 10.8% [3]. Consultation in obstetrics and gynecology was also the most used service in a leading Web-based medical consultation app in China [4]. Due to high demand and adherence, pregnant women have become a key target group for app developers.

Antenatal care apps (acAPPs) are a type of smartphone apps that provide prenatal care services and information targeting prepregnant and pregnant women. It is a new way of channeling information and interpersonal interaction in the current era of mobile technology development, which has been widely accepted [5,6]. A study in the United States showed that apps for women’s health and pregnancy accounted for 7% of all kinds of apps [7]. We found 110 maternal health-related apps on the Chinese app market. Functions of these apps were diverse although the provision of maternity-related information to pregnant women was the major one. This form of health guidance is superior to traditional methods and can even improve the quality of pregnancy care in areas with scarce medical resources [5,8-10]. Many apps also have social functions, professional counseling functions, and special tools, such as calculation of fetal movement, calculation of due date, and measurement of changes in body weight. These self-monitored health status functions can be used to track pregnant women’s health [5,8,11,12].

Although acAPPs are widely used, research on the relationship of such use with user health and especially mental health is scarce. At present, existing studies mainly focus on the use of apps for monitoring or intervening mental disorders. Sensors and apps of smartphones have been used to predict daily mood [13,14], detect depression [15-18], intervene depression [19], relieve pressure [20], and treat depression [18,19,21]. Mental health and app-related researches are even rarer, and their use and effect evaluation among pregnant women have not been reported. Pregnancy is a period of high incidence of mental disorders, which increases not only the risk of postpartum depression but also its severity [22-25].

There may be intergenerational negative effects from both physical and environmental aspects. Therefore, gestational depression has received much attention in recent years and was included in the category of perinatal depression by the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, in 2013. The use period of acAPPs overlaps with the occurrence of gestational depression. Whether there is a certain relationship between the two and what that relationship may be are the factors not only worthy of researchers’ attention in the field of maternal and child health but also important information for acAPP developers.

This study investigates the use of acAPPs in pregnant women at a specialized hospital for obstetrics and gynecology, examines antenatal depression, and explores the correlation between the use of acAPPs and mental health during pregnancy. These results can provide direction and theoretical basis for the development of future acAPPs.

This study was a cross-sectional survey carried out in Changsha, China, which revealed that the usage of acAPPs was very high (930/1304, 71.40% of the participants had used one) and frequent (457/930, 49.4% of the users used it 1-2 times per day) among pregnant women in urban areas. After controlling for several confounding factors, functions and duration of the use of acAPPs during pregnancy were found to be related to the incidence of antenatal depression. This reminds us that when considering pregnant women’s health education, it is important to look beyond traditional pregnancy schools and maternal and child special education and recognize the usefulness of acAPPs as mobile medicine is expected to become a new means of health education and management during pregnancy [9,31,32]. At the same time, acAPP design can be optimized by adding functions, such as disease screening, peer communication, and time reminders, to increase population coverage for pregnant women and mental health care.

This study revealed 4 important aspects of the use of acAPPs. First, it confirmed that mobile apps are becoming major ways to obtain health information [33]. Research in Australia [12] involving 410 women has found that nearly three-quarters of women used pregnancy-related apps and that most of them used these apps at least once a week. A Chinese study [6] found that 78.81% of expectant mothers downloaded pregnancy-related apps. These results are similar to our findings in terms of acAPP usage rate. Compared with traditional methods of information acquisition, antenatal care apps make it possible for pregnant women to find pregnancy care knowledge at their own time, free from the restrictions of work, life, transportation, and family environment, via broad availability of smartphones and network coverage. This could help save health service costs [34,35].

Second, just as the literature [12] has shown, pregnant women with different characteristics use acAPPs differently. In this study, family income, place of residence, education, first pregnancy, planned pregnancy, having no previous children, and opportunity to communicate with pregnant women of the same age affected the usage of acAPPs. These findings suggest that we should tailor the design of acAPPs to meet the characteristics of pregnant women. Furthermore, as vulnerable groups (older, lower income and education, and unplanned pregnancies) in general tend to use acAPPs less, acAPPs would need to be better designed to reach these populations.

Third, the process of selecting an acAPP is different from routine health care decisions that are more influenced by health care professionals. Most pregnant women rely on user evaluations to select acAPPs rather than professional recommendations, which makes it particularly important for acAPPs to be professional and accurate in terms of information content. In contrast to other entertainment apps, user evaluations of acAPPs are often comments on user-friendliness, and they do not discuss professionalism, accuracy, or comprehensiveness. Studies have shown that if the pregnancy information shared by apps is inaccurate and unreliable, users of these apps face risks in terms of pregnancy protection [36]. The regulation of health acAPPs is an important issue raised in the existing research [37,38]. There are also studies [39,40] suggesting that the incorporation of a medical editorial team can increase the reliability of the knowledge provided in acAPPs in order to meet the requirements of information demanders.

Finally, acAPPs may be designed to monitor and intervene in perinatal depression [41]. This study found that scores for depression were higher in pregnant women who focused on using the acAPP’s disease-screening functions. This may be because this group of pregnant women had underlying diseases or anxieties about their own health, leading their depressive symptoms to be more pronounced. The pregnant women who preferred acApps with social functions had a desire for communication, and the use of acAPPs also increased the opportunities for communication with other pregnant women and channels of release. Pregnant women can receive mutual support and comfort [42], rendering them relatively less at risk of depressive symptoms. Studies have confirmed that peer communication is a protective factor for depressive symptoms [43]. Interestingly, the study also found that depressive symptoms were more pronounced in pregnant women who used acApps for more than half an hour. This may be because such pregnant women are isolated from the real world or have obstacles in their interpersonal relationships, leading to their immersion in the Internet [44]. This is consistent with the findings of Mansourian et al [45]. Augner et al [46,47] also found that overuse of smartphones is one of the predictors of adolescent depression. This suggests that when developers design acAPPs, proper tools, such as adding a time-use reminder function, may help users arrange rest time. AcAPPs with disease-screening functions that provide health consultations and psychological guidance could reduce the risk of antenatal depression. Adding related content and functions to acAPPs would also make them better tools for pregnancy management.

This study is a cross-sectional survey of all expecting mothers present at the Provincial Maternal and Child Care Hospital during a selected period of time; thus, data extrapolation was limited and no causal inference could be made. In addition, the self-made questionnaires used in this study were only perfected in the pre-experiment and had not been tested for reliability and validity. There is also heterogeneity in the types of antenatal care apps. In future studies, authors should consider quality evaluation and fine classification before conducting in-depth analyses. Our team used the mystery customer approach to evaluate the acAPPs’ accuracy and reliability, the results of which will be described in another article.