PPD is a crucial part of the spectrum of mood disturbances affecting postpartum women. A variety of factors affect the physical and mental health of pregnant women. Thus, identifying alterable risk factors for PPD and controlling them at an early stage are essential for the treatment and prevention of this condition.
The psychosocial risk factors for postpartum depression in Chinese women identified in this meta-analysis mainly included three kinds: prenatal emotional factors (prenatal anxiety and prenatal depression), social demographic factors (poor marital relationship, poor living conditions, lack of social support and unplanned pregnancy) and social and interpersonal factors (poor relationship between husband and wife, poor relationship between mother-in-law and daughter-in-law and mother-in-law as the caregiver). First, prenatal anxiety and depression were significantly associated with an increased risk of PPD, as confirmed by some Western studies. An Italian study61 showed that women with depression or anxiety during pregnancy and a lack of support from family and friends were at a higher risk of postpartum depression. This result has also been confirmed in China. According to the report of Lee13, most postpartum depression was the continuation of prenatal psychological problems and emotional disorders, indicating that there was a significant correlation between prenatal psychological status and the occurrence of postpartum depression.
Another explanation for the effect of prenatal emotional distress is physiological changes. For example, excessive anxiety and depression in pregnant women may lead to a series of physiological and pathological reactions, such as a decrease in norepinephrine secretion and changes in other endocrine hormones, which may lead to the weakening of uterine contractions, a prolonged stage of labor and increased bleeding. These challenges further aggravate the anxiety of pregnant women and lead to an increased risk of developing PPD62.
Second, this study found that social demographic factors were also risk factors for postpartum depression, such as a poor economic foundation, poor living conditions, a lack of social support and unplanned pregnancy. Among them, the economic foundation of the family had an important effect on the psychological status of the mother. Previous reviews suggested that the status of the family's economic income was positively related to the level of stress in pregnant women. Yu42 suggested that after adjustments were made for other related factors, the incidence of postpartum depression among women who were worried about family economic status was 3.162 times higher than among those who did not worry about it. The probable explanation may be that after childbirth, the cost of raising the baby and the basic cost of living for the family significantly increased. If the family income is insufficient, it will lead to high levels of pressure for pregnant women and easily cause negative emotions. In recent years, with China’s two-child policy, raising multiple children in a family increases the family's financial burden, which may be a factor of PPD. A study in Turkey shows that there was a significant relationship between monthly income and depression, which was similar to the results of the present study63.
In addition, previous studies have shown that social support was a protective factor against postpartum depression, and as far as mothers were concerned, the greatest social support comes from their husbands. Xiong et al64 suggested that puerperae with spousal support were much less likely to develop postpartum depression. A Chinese study also confirmed that high levels of social support can reduce the risk of postpartum depression, with other factors were fixed23. Our findings are generally consistent with those of previous reviews. Eastern and Western women differ considerably in terms of social and cultural systems, and these differences have an impact on many aspects after delivery. For example, in Taiwan, family relations play a dominant role in social communication. During puerperium in traditional Chinese culture, women are often taken care of by relatives for at least one month. Traditional postnatal practices and family support protect the health and well-being of women after childbirth in China. In contrast, the absence of support for these practices among Chinese migrants in Western societies may have negative implications for their health65. Therefore, giving adequate social support to parturients during the puerperal period can help them get through this critical period smoothly.
Third, in this study, the interpersonal risk factors for postpartum depression were a poor relationship between husband and wife, a poor relationship between mother-in-law and daughter-in-law and mother-in-law as the caregiver. The poor relationship between husbands and wives, as an important factor affecting human physical and mental health, has attracted the close attention of researchers worldwide. Zhang66 suggested that the quality of the husband-wife relationship was mainly reflected in the quality of the husband's care for his wife, and women who were less satisfied with their husband's care were more likely to have depression. Poor marriage and family relationships will not only reduce maternal social support but also become a maternal stressful life event, which brings about an increased risk of developing PPD. This study was confirmed in a Polish study. Malus et al67 confirmed the significance of the marital relationship in the development of postpartum depression. A sense of closeness and intimacy in the relationship were associated with better mood and a greater ability to cope with the difficulties of labor, puerperium, and caring for a newborn baby.
In addition, the results of this study found that the risk factors for postpartum depression related to Chinese cultural characteristics included the mother-in-law as the caregiver and a poor relationship between mother-in-law and daughter-in-law. Traditionally, mothers-in-law exercise significant power in the family and are a major influence on the postpartum care of new mothers. In China, due to the influence of doing-the-month culture, mothers and newborns are mostly cared for by their mothers-in-law. The strain between mothers-in-law and daughters-in-law is a sensitive problem and may be a cause of PPD in China. Steinberg68 indicated that the strain between mothers-in-law and daughters-in-law often offset the benefits of assistance and may even contribute to negative mood during the postpartum period. In traditional Confucian philosophy, the new mother should be considered a good daughter-in-law if they behave in a way that is respectful at home and are obedient to their in-laws and husband69. The relationship between women and their parents-in-law is based on the environment rather than consanguinity. Sometimes they were reluctant to express their own feelings and opinions to their in-laws. New mothers feel very stressed when they have opinions different from their care providers. The situation may become even worse when conflicts occur with mothers-in-law. Because of the differences in backgrounds, values, identity, and logic of ideas, conflicts with respect to childcare between women and their mothers-in-law become prominent17. Meanwhile, the birth of newborns makes both of them focus on their children, and both want to spend more time with their children and grow closer to them. Because of the possessive and exclusive nature of love, competition and conflicts inevitably arise between them. In addition, after the birth, the focus of the attention of the mothers-in-law shifted from the new mother to the newborn, causing the new mother to feel left out, which brings about an increased risk of developing PPD70. Pregnant women think that they should be rewarded and valued for "carrying on the family line", but the gap between reality and ideals leads to maternal depression. Additionally, in China, because of the close relationship between the son and his original family, he will be on his mother's side when conflicts occur between family members. Wives’ lack of support from husbands can lead to marital disharmony, which is also an important risk factor for PPD.
This study had several inevitable limitations. First, some risk factors have received less attention; for example, nonuniform measurement standards and statistical difficulties have not been combined, such as the type of residence, postpartum wound recovery, postpartum work stress, and maternal occupation. Second, postpartum depression is the result of the interaction of multiple factors, but due to methodological limitations, it is difficult to investigate the interaction among risk factors. Third, in terms of language selection, this study only includes literature in Chinese and English, which may lead to bias in the comprehensiveness of the literature search, thus affecting the research results and the intensity of the argument.
In addition, this study covers a wide range of research sites, including pregnant Chinese women in mainland China, Hong Kong and overseas. Although some Chinese women have emigrated overseas, because they have been influenced by traditional Chinese culture for a long period of time, their way of thinking and living habits are still similar to those of individuals in their motherland.