Childbearing is one of the main factors of population dynamics and plays an important role in the change in population size and structure (1, 2). This phenomenon is a multidimensional concept with familial, social, economic, cultural, political, and religious implications (3). One of the significant concerns, which began at the end of the 19th century, is the decreasing fertility rate, which has been felt throughout the world (4–6).
Iran as a developing country, has experienced a sharp decline in the fertility rate, and during the last three decades (7), the total fertility rate (TFR), has fallen from 6.3 in 1986 to 1.62 in 2018(8). It is estimated that Iran’s population growth will reach 1% by 2025 (9) and will fall to less than 1% by 2031 (10). This is while in the religious and cultural context of Iran, having children is a virtue and one of the main motivations for getting married and starting a family, and couples’ families expect couples to have their first child soon after marriage (11).
One of the main causes of the fertility rate decline is changing fertility patterns and the increasing average age at marriage (12). Delayed childbearing increases the risk of unintended infertility and limits the number of children in each family (13). However, studies have shown that couples believe that their reproductive behavior is completely under their control and are often unaware of the consequences of late conception and increasing age at first pregnancy (2, 14). Increasing parental age is associated with increased infertility and fertility risks such as miscarriage; ectopic pregnancy; multiple pregnancies; low birth weight; gestational hypertension and diabetes; maternal mortality; stillbirth; premature births; down syndrome; and birth defects including congenital heart disease, cleft palate, esophageal atresia, schizophrenia; poor neurodevelopment; and the likelihood of childhood cancer (13, 15, 16).
Unfortunately, Iranian women are largely unaware of the potential side effects of delaying childbirth, and the issue appears to be ignored by the Iranian health system (17). This lack of knowledge inadvertently exposes them to infertility and fertility disorders, thereby increasing the need for Assisted Reproductive Technology (ART) (18). Despite the considerable advances in ART methods as well as the public imagination and expectations regarding the successfulness of these methods, they still cannot produce conclusive childbearing or compensate for the decline in fertility as women age (19, 20). Even in developed countries, neither women nor men fully understand the effect of age on fertility and this lack of knowledge is more common among men who are unaware of the negative effects of age, smoking, consuming alcoholic beverages, and obesity on fertility (21, 22). Currently, many public policies are being considered to reduce such effects (23). Consequently, in 2013, Iran enacted the Family Support Law to address these issues. However, proper implementation requires a change in the attitude of couples (24).
Since behavioral intention is a key factor in the performance of that behavior (2), it can be concluded that one effective way to change people's behavioral intention is to educate them individually or in groups to increase knowledge about fertility and change their intention (19). Based on research, the use of theoretical models and frameworks in the design of such educational activities can increase their effectiveness (25). Recently, the TPB has been used as a framework to address this issue, as its effectiveness in childbearing has been demonstrated in several studies (8) and it can help to understand how couples make decisions about having a child by establishing a link between attitudes and behaviors (26, 27). According to the TPB, three determining factors influence behavioral intention: 1- the attitude, 2- subjective norms, and 3- perceived behavioral control (25, 28).
In European countries, the intention to have a first child is influenced by attitudes towards having children and subjective norms (2). To encourage couples to decide to have children, it is necessary to find a way to alter their attitudes and subjective norms and the three components of TPB can help achieve this goal (26). The TPB provides important information about what influences behavioral intentions but does not adequately explain the extent and manner of desired behavior change (29). For this purpose, the TTM model can well describe the process of change or how people move toward the desired change (30, 31). Knowing where a person is in the stage of change is useful for designing appropriate interventions that encourage the person to make the desired changes (32). The TTM model includes 5 constructs: stages of change, the process of change, levels of change, self-efficacy, and decision balance; The most popular of these is "stages of change", which can determine how health behaviors change (33). This dimension has 6 steps: Pre-contemplation, Contemplation, Preparation, Action, Maintenance, and Termination (34). The effectiveness of this theory in changing behavior has been confirmed in several fields, and an intervention study in Iran also used this theory to change childbearing behavior (26). However, limited research has used a combination of these two models to change behavior, and based on a review, a combination of these two theories has been used to change healthy behavior in exercise, cancer screening, diet, and smoking behavior (34).
The average age of marriage in Iran is 27 (35). About 30% of women experience their first pregnancy within 5 years of marriage, and about 4% remain childless after 10 years of marriage (17). On the other hand, female infertility starts to increase from the age of 30, and by the age of 40, 1 in 6 women are no longer able to conceive, and after age 40, more than half of women lose their ability to conceive (21). Therefore, the present study intends to provide them with the right information before facing the decline in fertility. The assumption is that informing couples can help them make appropriate decisions about having children so that even fewer couples will suffer mental and physical disability from infertility and its high medical costs in the future. On the other hand, it is necessary to minimize the consequences of an aging society to an appropriate level. In this study, the plan is to use the TPB theory to train people and measure people's behavior changes after an intervention based on the TTM model, because this model is very effective in accurately measuring the stages of change and the amount of change.
Hypothesis
An educational intervention based on the integration of TTM and TPB on the intention to have a child in childless couples leads to changes in knowledge, attitude, subjective norms, perceived behavioral control, and intention to have a child, which in turn changes behavior, which can lead to strategies to solve problems related to the aging population.