Depression is a chronic medical illness that can affect thoughts, mood, and physical health, and becoming a leading cause of disability and overall global burden of disease worldwide[1]. According to the World Health Organization, about 350 million people suffer from it[2], and the prevalence of major depressive disorders is 4.33% worldwide[3],and 6% in China[4]. It has significant impact on the individual medical expenditure, contributing to 7.8% of total personal expected medical spending in China on the basis of the 2012 China Family Panel Studies survey[5]. Studies have shown that depression affects women more than men, of which reproductive age takes the highest risk[6]. Among them, pregnancy and postpartum easily lead to the onset and recurrence of mental illness, and depression and anxiety are the most common [7, 8].
The prevalence of antenatal depression ranges from 5.2–17.8% worldwide[9], which can be partly explained by the negative effects of fluctuations in gonadotropin levels during pregnancy on neurotransmitter levels and functional differences in the hypothalamus-pituitary-adrenal axis [10]. Women with antenatal depression appear to be at considerably higher risk for self-harm or suicide, failure to seek prenatal care, poor diet[11, 12], which may lead to the adverse pregnancy outcomes(like complications during pregnancy, premature birth, dysplasia of the fetus, low birth weight of the baby) [13, 14]. Moreover, a study had shown that women were more vulnerable to psychiatric illness after birth[15]. The incidence of postpartum depression is 6.7% in China and there is a rising trend[16]. As well, postpartum depression also predicts shorter breastfeeding time [17] and may be a risk factor for children with low social capacity [18]. Existing literature shows that factors associated with pregnancy and postpartum depression mainly include sociodemographic characteristics(e.g. age, marital status, education, income, complications of pregnancy) [14, 19–21], social support [22], and family function[23].
Social support is defined as instrumental, informational and emotional support provided by a social network including family, friends and neighborhoods, which could protect psychological well-being through buffering the effects of traumatic life events[24]. It can be characterized by the provider of support, including support from a spouse, relatives or friends, each thought to have independent protective effects against depression [25]. Social support as a protective and modifiable factor has been well investigated in relation to antenatal or postpartum depression[26]. Some studies have also proved that low-level social support were risk factors for antenatal and postpartum depression[27, 28]. And then, family ties will strengthen, same as the Tarkka’s and Lepistö, S’s studies that social support has been considered an important resource to improve family functioning [29, 30].
Family function can be defined as the degree to which a family performs as a unit to manage conditions, activities, external stimuli or events that cause stress[31]. Compared to healthy families, families with family dysfunction are expressed as lower cohesion, lower warmth, and expressiveness and higher conflict, rigidity, and affectionless control[23]. Previous studies had shown that depression is negatively correlated with family functioning [32, 33]. Improvement of family function may contribute to better prognosis of depression[34].In addition, Wang Y et al (2019) proposed a model that family function moderated the indirect relationship between social support and depression in the elderly[35].
The availability of mental health resources in rural areas of China is low[36]. Studies have shown that living in rural areas of China strongly significantly associated with antenatal and postpartum depression[37]. Despite previous studies have demonstrated the relationship between family function and depression as well as social support and depression, few studies have included these three variables in one study to understand the interrelationships and potential mechanisms of social support, family function and depression among antenatal and postpartum women. We examined the influence of social support and family function on the antenatal and postpartum depression in rural areas of southwest China in this study. Based on the previous research, we hypothesized a single mediator model shown in Fig. 1. Specifically, social support would be positively associated with family function (hypothesis 1) and negatively associated with depression (hypothesis 2). We also hypothesized that the family function would be negatively associated with depression (hypothesis 3). In addition, we suggested that the relationship between social support and depression would be mediated by the family function (hypothesis 4). The findings of this study identified the key factors that contribute to the prevention and control of depression in antenatal and postpartum women, which is of great significance for decreasing depression and improving the health of antenatal and postpartum women.