The Rate and Risk Factors of Postpartum Depression in Vietnam From 2010 to 2020: A Literature Review

Background: Postpartum depression (PPD) is commonly seen in women after birth and can lead to adverse effects on both the health of mothers and child(ren) development. In Vietnam, there have been a number of studies examining the rate and risk factors of PPD, but none has provided a systematic review. Aim: This current literature review aims to summarize and synthesize the current state of knowledge of studies conducted in Vietnam to provide a comprehensive understanding of the PPD phenomena during the last 10 years. Data Sources: A literature search was conducted relying on the most common online databases—MEDLINE/PubMed, ScienceDirect, and Google Scholar, which included articles if they (i) examined prevalence or risk factors of PPD; (ii) were conducted among Vietnamese participants using either quantitative, qualitative, or mixed-method, and (iii) were published from 2010 to 2020. After the filtering process, 18 articles were eligible to be reviewed. Results: Research studies in Vietnam on PPD are conducted among women at and after 1-month delivery. The rate of PPD reported in Vietnam among mothers at postnatal time points from 1 to 12 months ranged from 8.2 to 48.1%. Risk factors can be clustered into three groups: personal factors, family factors, and environmental factors. Recommendation: Further research studies should focus on examining PPD at an earlier stage within the first month after birth. The investigation of risk factors in a comprehensive manner for Vietnamese mothers would also be recommended.

onset at week 4-6 may last for more than 2 weeks or up to 1 year or later with some cases needing professional care (Stewart et al., 2003). Additionally, previous studies indicated other common mental health changes after birth. Baby blues (transient emotional lability phase) and postpartum adjustment, which both start within early weeks postpartum, are mostly recovered without treatment (Helle et al., 2016;Mokhtaryan et al., 2016). Postpartum anxiety (including both clinical psychiatric disorders and a dimensional level of general anxiety) and postpartum psychosis (very rarely) occurring within the first 2 weeks, but the duration can be weeks or months and almost all of cases required hospitalization due to its severity (Stewart et al., 2003;Stewart and Vigod, 2016). However, a large number of recently published articles with findings varying across countries focus only on the prevalence of PPD as the most common mental disorder. Among Asian regions, the prevalence was 36% in Pakistan (Husain et al., 2006), 30.2% in Taiwan (Chien et al., 2006), or 16.8% in Thailand (Limlomwongse and Liabsuetrakul, 2006).
Risk factors associated with PPD include personal issues such as a low level of education background (Do et al., 2018;Wesselhoeft et al., 2020) or a history of mental health disorders (Silverman et al., 2017;Tho Tran et al., 2018). Other reasons, such as infant gender among areas where local residents remained traditionally unscientific belief (Murray et al., 2015), intimate partner violence (Tho Nhi et al., 2019), or stressful life events (SLEs) like a job loss, death of loved one, or an economic shock (Qobadi et al., 2016;Gausman et al., 2020), can worsen the situation of PPD. Prospective studies have shown that PPD may also lead to impaired physical, mental development for children and lower life quality, or even suicidal or self-harming behaviors of a mother (Herba et al., 2016;Gressier et al., 2017;Haddad et al., 2017;Tungchama et al., 2017). In Vietnam, there have been a number of studies about the rate and risk factors of PPD using different screening, including the Edinburgh Postnatal Depression Scale (EPDS) (Chen et al., 2012;Van Vo et al., 2017;Do et al., 2018;Wesselhoeft et al., 2020), Self-Reporting Questionaire-20 (SRQ-20) (Upadhyay et al., 2019;Gausman et al., 2020), or diagnostic guide as the Diagnostic and Statistical Manual of Mental Disorders (DSM) . This current literature review aims to summarize and synthesize the current state of knowledge about PPD in Vietnam. The central question is what is the PPD rate and the risk factors examined among Vietnamese women?

METHOD Search Strategies
A literature search was conducted on the following online databases: MEDLINE/PubMed, ScienceDirect, and Google Scholar. In both Vietnamese and English, search terms included Vietnam, depressive * , postpartum were used separately and as combination during the search. Only research articles published within the last 10 years matching these key terms were eligible. The reference list of published articles led to other related studies. Following the initial search, all results, titles, abstracts, and full texts were filtered and reviewed before being included in this study. Some studies that examined both prevalence and risk factors were only counted as one. Figure 1 illustrates the search process.

Inclusion and Exclusion Criteria
Articles were included if they (i) examined the prevalence of risk factors of postpartum common mental disorders with any measurement scale; (ii) were conducted among Vietnamese participants using either quantitative, qualitative, or mixed methods. While quantitative studies illustrated obvious numbers and possible associations between PPD and its related predictors, qualitative research presented experiences of new mothers in the contexts of their socio-cultural; and (iii) were published within the last 10 years from 2010 to 2020.

Analysis Method
Eligible articles were reviewed by two separate individuals in order to ensure the credibility of the findings. A literature review matrix as below (Table 1), which included author, year, objectives, setting, measurement tool, time point screened, prevalence, risk factors, was used to criticize articles.

Characteristics of Articles About Postpartum Depression in Vietnam Published From 2010 to 2020
The search strategies resulted in 47 abstracts from studies conducted among Vietnamese participants. Among those, 14 articles were excluded due to unrelated objectives that did not examine any rate or risk factors. Next, 15 articles were eliminated after a full-text review, which indicated that the postnatal screening time point was unclear or focused on antenatal or perinatal period instead of postpartum. In the end, 18 research articles met the criteria to be reviewed in this literature review.
As presented in Table 2 regarding the characteristics of eligible articles, from 2010, it can be seen that four studies (22.22%) used a qualitative approach, whereas others were undertaken using quantitative methods, including a cross-sectional study (n = 8; 44.45%) or a cohort study (n = 6; 33.33%). About 83% (n = 15) studies had a sample size of more than 100 mothers. The research settings included four (22.22%) studies conducted at commune health centers, five (27.78%) at district hospitals, five (27.78%) at provincial hospitals, and four (22.22%) at national hospitals. Tools and guidelines used to screen or diagnose PPD differed from each study. The most frequently used screening tool was the EPDS regardless of different versions or cutoff point (n = 9; 50%), followed by DSM diagnosis criteria (n = 4; 22.22%), SRQ-20 (n = 3; 16.67%), and others (n = 2; 11.11%). Postnatal screening time for PPD was between 1 and 3 months (n = 8; 44.45%), between 4 and 6 months (n = 4; 22.22%), and up to or later than 12 months (n = 6; 33.33%).

Rate of Postpartum Depression in Vietnam Reported by Articles Published From 2010 to 2020
The time diagram (Figure 2) illustrated the rate of PPD following the postnatal screening time points from 1 month after birth. Among articles that met the criteria to be chosen for review, 14 (77.78%) of them examined the prevalence of PPD with a clearly defined time point. Most studies used the EPDS measurement scale (n = 9; 50%).
No study was performed among Vietnamese participants in the early time after birth, especially days within the first 2 weeks.
From the first month to the third month, research revealed a wide range for the rate of PPD. The highest reported rate was ∼34% (33.6 and 34.3%) in two different research settings. One study used EPDS to compare the rate of PPD between married, immigrant women from Vietnam and native Korean mothers within 12 weeks (Choi et al., 2012). The other used DSM  (Whooley et al., 1997) 1-3 months 23% Young age, being a first-time mother and having achieved higher educational levels were significantly more frequent in the group lacking confidence.

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Frontiers in Psychology | www.frontiersin.org Over 1 year and 2 years Mental preparation when the baby is born Husband's sharing concern Physiological characteristics of the child Mother's knowledge and experience of raising children The unity of husband and wife, mother-in-law in raising children.

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Common mental disorders among women, social circumstances and toddler growth in rural Vietnam: a population-based prospective study Fisher et al. (2015) To examine the effect of maternal common mental disorders (CMD) and social adversity in the post-partum year on toddler's length-for-age index in a rural low-income setting.  Le (2015) To examine the current mental health problems of mothers before giving birth (6-9 months) and after giving birth (3 months).
To understand some socio-cultural factors and psychological traumas that are risk factors of PPD in mothers.
To determine the incidence and rates of recovery from common mental disorders (CMD) among rural Vietnamese women and the risk and protective factors associated with these outcomes from the perinatal period to 15 months after giving birth.
diagnosis criteria to examine the effect of maternal common mental disorders and social adversities in the postpartum year in a rural low-income setting in Vietnam . In contrast, the lowest rate of PPD (8.2%) was screened by EPDS in a part of a cohort study investigating the association between emotional experience with a present partner and postnatal depressive symptoms among women in Vietnam (Tho Tran et al., 2018). Two studies performed between the first and the sixth month demonstrated a high rate of PPD. Both studies used EPDS with a similar sample size (465 and 600 participants) and research settings to estimate the rate of postnatal depressive symptoms amongst women in central Vietnam, ranging from 19.3 to 37.1% (Murray et al., 2015;Van Vo et al., 2017).
Four studies examined a later postnatal time of up to more than 1 year. In these studies, the rate was about 20% (18.5-24%). Three out of four studies looking at this period used the SRQ-20 measurement scale Upadhyay et al., 2019;Gausman et al., 2020). These studies shared common features as design (a cross-sectional study), sample range (>1,000 participants), and research setting (at country level).

Risk Factors of Postpartum Depression Reported by Articles in Vietnam Published From 2010 to 2020
As summarized in Table 3, there are a number of risk factors contributing to PPD, as revealed in 16 studies.
Findings from both quantitative and qualitative research were included to illustrate the association between PPD and risk factors.
Among personal factors, a low level of education was pointed out as a risk factor of PPD. In particular, mothers with primary or secondary school education had a higher risk of PPD compared to ones with high school education [odds ratio (OR) = 2.17; 95% CI: 1.21-3.89 and OR = 3.55; 95% CI: 1.74-7.25, respectively]) in a study by Tho Tran et al. (2018). Similarly, research by Wesselhoeft et al. in 2020 concluded that the highest level of education (university/college) was associated with a significantly lower EPDS total score when adjusting for country (p < 0.001) (Wesselhoeft et al., 2020). Poor knowledge, lack of experience about PPD, poorly prepared to be a mother from a psychological perspective, and feeling unsatisfied about new life after birth were revealed as personal factors leading to PPD in qualitative studies (Tran, 2010;Le, 2015;Abrams et al., 2016). Finally, new mothers with a history of mental trauma were more likely to be exposed to PPD, as indicated in both qualitative (Abrams et al., 2016) and quantitative studies (Tho Tran et al., 2018).
Family factors can be considered as a major cause of PPD. Lack of family support appeared to be a predictor of PPD in three quantitative studies with an OR of about 3.5 (Fisher et al., 2010;Tho Tran et al., 2018;Tho Nhi et al., 2019). Poor relationships with family members and lack of family support were also identified as risk factors of PPD in case of happening together in qualitative studies (Tran, 2010;Fisher et al., 2015;Murray et al., 2015;Tran et al., 2018). Mothers caring for a sick child were more likely to be predisposed to PPD, as indicated in studies with OR of 1.6 and 2.2, respectively Tho Tran et al., 2018). Intimate partner violence, including physical, emotional, and sexual violence, was revealed as a risk factor of PPD in quantitative studies (OR ranged from 2.11 to 5.08) (Fisher et al., 2010;Tho Nhi et al., 2019). Lastly, the preference for a son by the husband was also a typical and cultural risk factor of PPD for his wife, with an OR between 1.78 and 1.98 (Tho Tran et al., 2018;Tho Nhi et al., 2019).
With regard to environmental factors, SLEs appeared to be a significant factor leading to PPD of new mothers. SLEs, such as an economic shock or coincidental life adversity, revealed a strong association with PPD as indicated in two quantitative studies (OR = 2.34; OR = 4.40, respectively) (Fisher et al., 2010;Nguyen et al., 2016). Living in rural areas and lack of social support/reaction were also found as risk factors of PPD in two qualitative studies (Abrams et al., 2016). These risk factors were also confirmed in quantitative studies that people living in a rural area and lack social support had 2.82-and 4.4-times higher risk of PPD exposure, respectively (Fisher et al., 2010;Nguyen et al., 2016). The confinement, which refers to traditional practice, especially in Eastern countries, includes enforced rest, lying over heat, not bathing for a particular period, and following specific recipes (Murray et al., 2015). These practices beginning immediately after birth and lasting for a culturally variable length were risk factors for PPD, as mentioned in qualitative interviews about postnatal depressive symptoms among women in central Vietnam (Murray et al., 2015).

DISCUSSION
Eighteen eligible articles published in the last 10 years were reviewed and summarized in this literature review. The results reflected the differences in study designs, including the characteristics of participants, the use of screening scales, and the postnatal screening time point for PPD. All these components led to a wide range in the rate of PPD among Vietnamese participants (8.2-37.1%).
The different postnatal time points when PPD was screened can lead to various rates, especially during the early period after birth. Many studies about postpartum emotional disorders among women during few days/weeks after birth were alarming regarding its high prevalence (44.3% in Hong Kong, 31.3% in Nigeria, and 58% in India) (Mokhtaryan et al., 2016) and its prediction of further PPD (Reck et al., 2009). Postpartum psychosis, a more serious condition, was also mentioned during this time, however with lower rate, from 0.89 to 2.6 in 1,000 women in a systematic review (VanderKruik et al., 2017). However, no data were reported explicitly about the rate of PPD within the first month after birth. There is a definitive lack of data in the literature about this mental health issue at the early stage of within the first month after birth among Vietnamese participants during the last 10 years.
In many countries, EPDS was the most commonly used instrument to screen PPD (Klainin and Arthur, 2009;Hegde et al., 2012;Özcan et al., 2017;VanderKruik et al., 2017). Research by Santos et al. (2007), when comparing the validity of EPDS and SRQ-20, confirmed the reliability of EPDS for screening PPD with sensitivity 82.7% (74.0-89.4%) at the best cutoff point ≥10 and specificity 65.3% (59.4-71.0%) (Santos et al., 2007). In this literature review in Vietnam, EPDS, DSM diagnosis criteria, and a two-question case-finding instrument by Whooley et al. in 1997 were all used to point out the rate of PPD during the first 3 months. In particular, studies examined the earlier postnatal time (6 months or less) preferred EPDS, whereas studies conducted at time points later than 6 months used SRQ-20. Even so, the purposes of using EPDS, SRQ-20, and DSM were different from each other, leading to a variety of reported rates. However, while EPDS and SRQ-20 are considered as screening tools for mental disorders (PPD) by healthcare workers (Santos et al., 2007), DSM is diagnostic criteria for doctors or specialists in a confirmed diagnosis (De Jesus Mari and Williams, 1986;Frances et al., 1995;Cox and Holden, 2003).
Although the same measurement scale was used, the rate can still be different due to the variance in characteristics of participants. Most research in Vietnam focused on examining the PPD at the postnatal time points of between 1 month and 3 months, with the rate from 8.2 to 34.3%. Regardless of using EPDS, while research by Tho Nhi et al. in 2019 among women at 4 and 12 weeks after delivery in 24 communities in Dong Anh District (Hanoi, Vietnam) pointed to a lower rate at 8.2% , a study conducted in Korea to compare PPD between married immigrant women from Vietnam and native Korean mothers revealed a much higher rate at 34.3% (Choi et al., 2012). This difference came from characteristics of participants and research settings. Participants from the study conducted in Korea were immigrant women vulnerable to depression due to

Factors Indicated by research in Vietnam
The number of qualitative studies revealed Strength of the relationship in quantitative studies*

Personal factors
Low level of education (Murray et al., 2015;Tho Tran et al., 2018;Wesselhoeft et al., 2020) 2 OR = 2.17; 95% CI: 1.21-3.89 p < 0.001 (OR were not reported) Poor knowledge and lack of experience about PPD (Tran, 2010;Abrams et al., 2016) 2 Unwell-prepared psychology to be a mother (Tran, 2010;Tran et al., 2014) 2 Unsatisfaction about new life after birth (Le, 2015) 3 History of mental trauma Murray et al., 2015;Tho Tran et al., 2018)  mothers whose children aged from 15 days to 3 months (11.8%) and a study in Japan examined mothers at the age-specific 3 months after birth (14.8%) (Matsumoto et al., 2011;Silva et al., 2017). The differences in the reported rate of PPD may be caused by how PPD was defined, how PPD scales were translated, or the cutting point of PPD scales. The assessment of PPD at the postnatal time point of 6 months in this literature review showed significant differences in the rate of PPD (19.3 and 37.1%) despite similar sample sizes and research settings. About 37.1% was the rate at risk of PPD, with the cutting point of EPDS scale at 9/10 (Murray et al., 2015), whereas 19.3% was the rate for probable depression with the cutting point of EPDS at 12/13 (Van Vo et al., 2017). A study conducted in Korea to measure depression and/or anxiety among women 6 months after delivery using the EPDS scale with the cutting point of 12/13 also revealed a prevalence of 14.3% (Yeo, 2006). In comparison to some Asian countries with the similar culture, including India, Thailand, and Indonesia (the prevalence is 11-15, 8.4, and 18.37%, respectively), the prevalence of PPD in Vietnam is lower, whereas this prevalence is reported higher in a Taiwanese study (42.6%) (Chen et al., 2007;Hegde et al., 2012;Panyayong et al., 2013;Nurbaeti et al., 2018).
This literature review showed that studies conducted in more socio-economically developed areas revealed a lower rate of PPD at the period of 6 months after birth in Vietnam. It can be inferred that research settings may contribute as a risk factor of PPD. Research settings can be physical, social, and cultural sites (Given, 2008), including income, level of education, and information access. For instance, rural residents with economic issues or insufficiency of both mental health infrastructure and specialists are less likely to define themselves as needing care and lack of access to specialty mental health services (Gamm et al., 2010).
In terms of personal risk factors of PPD illustrated in research conducted in Vietnam, key points to consider can be lack of knowledge of mothers, lack of experience about PPD, and dissatisfaction about transitioning from previous life circumstances to a new reality. Providing essential information for new mothers was confirmed as a helpful method to reduce the risk of PPD in a study by Fiala et al. (2017). Based on the Knowledge, attitude and practices (KAP) model of Launiala in 2009, without sufficient knowledge, a mother cannot have the right attitude and proper practice regarding PPD prevention. Lack of preparation to be a mother and a history of mental trauma were mentioned as links to psychosocial factors in some research globally (Klainin and Arthur, 2009;Özcan et al., 2017).
Poor quality of relationships with family members and lack of family support were prominent causes of PPD. Research in India and Thailand reported marital conflict in depressed women as a factor independently associated with PPD (Hegde et al., 2012;Panyayong et al., 2013). A number of findings in other countries, such as Korea (Lee and Park, 2018), China (Xie et al., 2010), and the United States of America (Negron et al., 2013), emphasized the importance of support from family members, especially husbands to women with PPD. Xie et al. (2010) in a research related to Chinese culture also indicated that women might be more vulnerable to family support after birth due to physiological and psychological changes (Xie et al., 2010).
Most studies in Vietnam shared similar findings with those in India and Turkey that environmental factors, such as SLEs, were predictors of PPD (Hegde et al., 2012;Özcan et al., 2017;Upadhyay et al., 2019). A SLE can be the death of a close relative, assault, serious marital problems, or divorce/breakup, which was studied with an onset of an episode of major depression in women (Kendler et al., 2010). Additionally, cultural aspects, such as traditional confinement practice after birth or the preference for a son by the husband should be further assessed in relation to the PPD in Vietnam, following findings confirmed in Asian countries (Klainin and Arthur, 2009).

CONCLUSION
Most research about PPD conducted in Vietnam among women in the first 3 or 6 months after delivery revealed a rate of PPD from 8.2 to 37.1%. Measurement tools, postnatal time points, and research settings can impact the rate of PPD. Risk factors may result from the own characteristics of mothers, family relationships, or social environment.
Further studies of PPD in Vietnam should focus on women within the first month after birth. Although symptoms and signs of PPD can appear within the first few days after delivery, currently no research in Vietnam has been conducted at this early postnatal time point. The EPDS is recommended to screen for PPD as its validity and reliability have been confirmed. A comprehensive questionnaire to examine risk factors of PPD for Vietnamese women should also be developed.