The postpartum period is a critical period as it is a unique milestone for many of the important physical, emotional and social changes for parents and newborns (Nilsson, Danbjorg, Larsen, Clemensen, \& Kronborg, 2015). In this period, the mother can have problems such as bleeding, infection, pain, breast problems and fatigue. In addition, adaptation to the parenting role, eventual difficulties in adaptating this role and efforts to care for the newborn can reduce the quality of life (WHO, 2012). At the beginning of the postpartum period, mothers need education and support in many subjects such as parenting, baby care, breastfeeding and relevant information and effective care (Ellberg, Hogberg, \& Lindh, 2010). The World Health Organization (WHO) also emphasizes the need in the postpartum period suggesting that breastfeeding should be supported, nutrition provided, baby development monitored and family care needs met (WHO, 2013; WHO, 1998).

In recent years, research has shown that postpartum women use information and communication technologies more and more frequently (Gibson \& Hanson, 2013) to seek health information (Walker, Im, \& Vaughan, 2012). It has been shown that tele-applications for supporting and directing parents in the postnatal period are useful in the transition to parenting in studies from Sweden and Denmark (Lindberg, Christensson, \& Öhrling, 2009; Danbjorg, Wagner, \& Clemensen, 2014b). Mobile applications providing information on pregnancy health during the prenatal period are widely used (Kennelly, Ainscough, Lindsay, Gibney, McCarthy, \& McAuliffe, 2016). It has been shown that it may be possible to meet the support needs of parents by applying innovative communication methods such as online communication at an evidence-based knowledge base. Parents saw the phone application as an informative and navigational lifestyle. Meeting new parents' information needs with chats, knowledge based and automatic messages makes them feel safe and increases their self-sufficiency (Danbjorg, Wagner, \& Clemensen, 2014a; Danbjorg, Wagner, \& Clemensen, 2014b; Danbjorg, Wagner, Kristensen, \& Clemensen , 2015). It is not possible for nurses to be at their mother's side anytime during the whole postpartum period. It is not possible to give all the necessary information without leaving the hospital and transfer the information to practice on the mother's side.

In postpartum period, care needs are increasing so that parents can adapt to their new roles and give effective care to the newborn. It is very important for the mothers to manage this period effectively for their future well-being and relations (Nilsson et. al. 2015). Studies show that mothers and fathers do not get enough postnatal care, do not feel confident with the information they have and feel insecure about what they will do.It is important for parents to feel secure in the postpartum period which in turn will have postive effects on the baby´s health and wellbeing (Danbjorg, Wagner, Kristensen, \& Clemensen, 2015; Persson, Fridlund, Kvist, \& Dykes, 2011).

Security is defined to feel safe, to be ready, to be satisfied, to feel good and to be sure (Löf et al. 2006, Forster et al 2008, Lindberg et al 2009). Insecurity is a predominant emotion for parents and is characterized by unpredictablity, uncertainity, stress, anxiety, fear, suspicion, feelings of loneliness and despair (George 2005, Forster et al 2008, Hjalmhult and Lomborg 2012). Insecurity is associated with lack of knowledge and skills experienced by parents in newborn care (George 2005, Forster et al 2008, McLachlan et al. 2009). Parents that feel they can manage the baby wellness have sense of security (Löf et al. 2006). They feel safe when they know about the needs of their newborn and aware that they, the parents, are in control of their newborns health (Persson \& Dykes 2002). Parents sense of security was associated with the strengthening behaviors they received from health professionals; unity within the family - closeness; autonomy; the mother's physical well-being and the involvement of the father during the birth and the postpartum period (Persson \& Dykes, 2002; Persson, Fridlund, \& Dykes, 2007; Persson \& Dykes, 2009; Persson, Fridlund, Kvist, \& Dykes, 2011; Persson, Fridlund, Kvist, \& Dykes, 2012).

The postpartum period is a transitional period in which mixed emotions dominate the whole family. In this period, physical symptoms, sleep deprivation, changing demands in work and home life are usually stressful and wearing. Additionally stress anxiety symptomatology has a positive relationship in susceptible people (Moran, Polanin, \& Wenzel, 2014). Anxiety usually manifests itself as extreme and persistent fear, anxiety, tension and regularly includes physical symptoms such as sleeping difficulties and lack of focus (Dennis, Falah-Hassani, Brown, \& Vigod, 2016). In studies, the anxiety prevalence rates of mothers during the first postpartum year vary between 2% and 45% (Enatescu, et al., 2014; Martini, et al., 2013). Unfortunately, there is increasing evidence that postpartum anxiety affects maternal and infant health negatively. Fatigue, loss of self-esteem and bad body sensations were seen in women who had postpartum anxiety. A deterioration in mother-infant interaction and in sleep patterns, excessive crying and also a deterioration in social relationships was shown. As anxiety acts as a trigger for development of depression, depression is often accompanied by anxiety symptoms (Dennis, Falah-Hassani, Brown, \& Vigod, 2016). Depression is a common mental disorder characterized by depressed mood, loss of interest and enjoyment, reduced energy, guilt, low self-esteem, sleep disturbances, decreased appetite and problems in focusing. Depression is a very important health problem for all ages and genders around the world.The World Health Organization (WHO) states that by 2020, depression will contribute to 5.7% of the total illness burden. Depression is the most common type of disease in women (WHO, 2010). For many women, postpartum depression (PPD) usually occurs within the first 12 weeks after birth (Dennis \& Dowswell, 2013). PPD is characterized by symptoms consistent with major depressive disorders, bipolar disorders or brief psychotic disorders occurring within 4 weeks of birth (American Psychiatric Association 2013). The symptoms associated with PPD are hopelessness, worthlessness, feelings of guilt, dissatisfaction with one's activities, difficulty in sleeping and concentration and decision-making problems (Gross \& Marcussen, 2017). Depressive symptoms in the early postpartum period vary between 5% to 20% in mothers (Patel, Baiely, Jabeen, Ali, Barker, \& Osiezagha, 2012; Kerstis, Berglund, Engström, Edlund, Sylven, \& Aarts, 2014; O'Hara \& McCabe). Dissatisfaction with marriage, antenatal life events, past depressive symptoms, late antenatal depressive symptoms, lack of social support, stressful life events and marital conflicts were identified as potential risk factors for PPD (Dennis, Brown \& Morrell, 2016). PPDnegatively affects women's quality of life, close relationships, maternal-infant interactions and infantile and school-age child development outcomes. Early diagnosis and intervention is essential to ensure optimal care for mothers, children and families when short and long term sequels of PPD are considered (McDonald, et al., 2012).

Reducing feelings of loneliness and being lonely, preventing incompatible health behaviors or reactions, increasing individual motivation, providing access to medical services or providing information about benefits, directly affects the development of PPD by supporting health and well-being positively. It is also an indirect means of prevention to identify and reduce the stress factors, increase the number of coping strategies, teaching problem-solving techniques and supporting self-sufficiency (Dennis \& Dowswell, 2013). It is clear that there must be a very good support system for all of this to be accomplished. Postpartum support for the mother is of utmost importance (Danbjorg, Wagner, Kristensen, \& Clemensen, 2015). "Current social support", including family, friends and health professionals, is one of the factors that mediate the maternal roll (Barclay, Everitt, Rogan, \& Schmied 1997; Danbjorg, Wagner, Kristensen, \& Clemensen, 2015). In theese studies, it is seen that the support systems of the mothers discharged from hospital after birth are not enough and there is no follow up. The mothers also found it difficult to access the information they need immediately (instantly). Parents were disturbed by the thought that they would disturb nurses when they were looking for help (Danbjorg, Wagner, \& Clemensen, 2014a; Danbjorg, Wagner, \& Clemensen, 2014b; Danbjorg, Wagner, Kristensen, \& Clemensen, 2015). Mothers who are postpartum, spend a lot of time caring for their newborn, but they do not have enough time to get the information they need (Guerra-Reyes, Christie, Prabhakar, Harris, \& Siek, 2016). New ways of communicating between healthcare personnel and parents are necessary. More individual timely information increases the self-confidence of mothers (Danbjorg, Wagner, \& Clemensen, 2014a; Danbjorg, Wagner, \& Clemensen, 2014b; Danbjorg, Wagner, Kristensen, \& Clemensen, 2015). In the postpartum period, adequate care and support have been reported to be associated with positive health behaviors and health outcomes, maternal stress reduction and baby health improvement (Guerra-Reyes, Christie, Prabhakar, Harris, \& Siek, 2016). There has been no study evaluating the effects of mobile support application on postpartum sense of security, anxiety and depression during the postpartum period.

Conceptual framework of the study Orem's Self-care Deficit Nursing Theory is used as the conceptual framework of this study. Acording to Orem people have a natural ability for self care and that nursing should focus on affecting that ability there is a constant need for strength and energy in order for a person to move on with his life and ability. The person has the power to self-care for her/himself and others and to determine their needs. The self-care skill required to maintain the life and function of the adult person varies from person to person. The person explores and develops different ways in describing the requirements for himself and others, and the necessary power in total. People who live together and share their responsibilities as a group are held accountable for the care of both themselves and others suffering from inadequate self-care (Orem, 2001, Fitzpatrick \& Whall, 1996). The self-care of mothers who do not receive accurate health information may be affected. Likewise, the health of the children of mothers who do not get enough information is affected.