Trajectories of cognitive reactivity and its predictive value on postpartum depression in Chinese women: a latent class growth modeling analysis

Abstract Many women are experiencing postpartum depression (PPD) after giving birth. How to recognize and intervene in high-risk PPD women early and effectively remains unknown. Our objective is to describe the latent trajectory groups of cognitive reactivity (CR) in perinatal women, and their relationship to demographic and disease-related factors, as well as investigate the associations with PPD. Data from 321 perinatal women who were evaluated in urban tertiary hospitals in China at three-time points: 32-35 weeks of pregnancy, 1 week postpartum, and 6 weeks postpartum. Latent class growth modeling was used to identify the trajectory patterns of CR and logistic regression was used to explore the association between demographic and disease-related factors, CR trajectories, and depression. Three trajectory groups were identified: the continuing deterioration group (17.2%), the postpartum deterioration group (22.1%), and the consistent resilient group (60.7%). Participants with a bachelor’s degree or higher and with gestational diabetes diagnosis were more likely to be in the continuing deterioration group. Those who were from only-child families were more likely to be in the postpartum deterioration group. Women in the continuing deterioration group and postpartum deterioration group were more likely to experience PPD. Targeted interventions should be developed based on trajectory group of CR.


Introduction
Postpartum depression (PPD), a common non-psychotic depressive disorder, occurs after childbirth and can have serious consequences for the psychosocial and economic status of mothers, their spouses, newborn babies, and relatives [1-3].As a global phenomenon, low-and middle-income countries reportedly have a higher prevalence of PPD (9.29%-74.0%)than high-income countries (10.58%-21.5%)[4,5].In recent years, the prevention and treatment of PPD have gained increasing attention [6,7] and the early prevention of PPD has been listed as an important public health topic in many countries [8].However, how to recognize and intervene in high-risk PPD women early and effectively remains unknown.
Cognitive reactivity (CR), is defined as the ease with which negative cognitions can be (re-)activated by sad mood states, or mood-linked increases in dysfunctional attitudes after priming [9].Priming, in the context of psychology, refers to the process by which exposure to a stimulus influences or activates a person's subsequent thoughts, perceptions, or behaviors related to that stimulus [10].CR has been recognized as an important predictor of the development, maintenance, and relapse or recurrence of depressive symptoms or clinical depression [11][12][13].For example, Kruijt et al. reported high CR scores predicted the first onset of depression within two years in neverdepressed individuals [12].Figueroa et al. also reported that in depression-remitted patients, every 20-point increase in CR scores resulted in a10% to 15% increase in the risk of relapse [11].For perinatal women, Dowlati et al.'s cross-sectional design study found the level of dysfunctional attitudes was positively associated with postpartum blues [14].However, few studies have examined whether CR can structurally assess and predict the risk of depression symptoms during the perinatal period.
Several studies indicate CR is associated with certain sociodemographic factors including body mass index [15], monthly household income, as well as certain psychosocial factors such as rumination [16], neuroticism [17], and mindfulness [18].However, to date, neither factors that influence the course trajectories of CR in pregnant women have been identified nor the predictors of PPD development.Thus, our study aimed to: (i) identify distinct trajectories of CR among perinatal women, (ii) describe the sociodemographic and clinical predictors of trajectory groups of CR, and (iii) evaluate the association of trajectories of CR and PPD.

Design
This was a prospective cohort study conducted with pregnant women from the obstetrical clinic and obstetrical inpatient departments of four tertiary hospitals in Fuzhou, Putian, and Quanzhou City, Fujian Province, China from July 2020 to July 2021.The study adhered to the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement [19] and was approved by the ethics committees of Fujian Medical University (No 2017024).The convenience sampling method was used; a trained research staff member identified potential third-trimester women, screened them for eligibility, and obtained their written informed consent.The inclusion criteria were as follows: (i) age � 20 years, (ii) week 32-35 of pregnancy and fetal survival diagnosed by type-B ultrasonic test, (iii) a score � 12 on the 10-item Edinburgh Postnatal Depression Scale, and (iv) willing to be followed for up to six weeks postpartum.Women with a preexisting mental disorder or cognitive impairment were excluded.

Sample
Data was collected at three time points: 32-35 weeks of pregnancy (T1), one week postpartum (T2), and six weeks postpartum (T3).At T1, sociodemographic and clinical characteristics, CR, and depression symptoms were collected through face-to-face interviews.The researchers followed up with the participant at the T2 and T3 time points by telephone to assess levels of CR and depression through use of a survey.A total of 93.3% of the 344 identified women completed the survey online (n ¼ 321).The collected questionnaires were collapsed later based on telephone numbers of the participants at three-time points using SPSS.The analyses were conducted on women who completed at least three CR measurements between 32-35 weeks of pregnancy and six weeks postpartum.

Edinburgh postnatal depression scale (EPDS)
The 10-item self-reported EPDS is the most commonly used scale for screening women with perinatal depression [20].Items are scored on a four-point scale that ranges from 0 to 3, with higher total scores indicating more symptoms of depression (range, 0-30).The EPDS has been validated in many countries, including a Chinese and Pakistani version, and has good psychometric properties in perinatal contexts [21].When assessing for PPD, a recommended cutoff score is 13 or higher, while an EPDS score of < ¼12 indicates a lower likelihood of PPD [20].Acceptable reliability of the scale's overall score was attained in this study (Cronbach's a ¼ 0.87-0.90).

The leiden index of depression sensitivity -revised revision -Chinese version (LEIDS-RR-CV)
The 26-item self-reported LEIDS-RR-CV was used to measure CR.It was comprised of five subscales: Hopelessness/ Suicidality (five items), Acceptance/Coping (four items), Aggression (five items), Control/Perfectionism (five items), and Avoidant Coping (seven items).Items were rated on a five-point Likert-type scale ranging from 1 (not at all) to 5 (very strongly).The Acceptance/Coping subscale was reverse-scored and the scores for each item were summed.Higher total scores indicated greater CR.The LEIDS-RR-CV has been validated and has been found to have good psychometric properties.In this study, Cronbach's a for the total scale was 0.928-0.982.The cutoff value for the Clinical Rating (CR) to identify women at a high risk of depression symptoms at six weeks postpartum was 60.

Sociodemographic and clinical characteristics
Sociodemographic and clinical information from the administrative database of the participating hospital was collected, including telephone numbers, maternal age, weight (kg), height (cm), education level, whether the woman was an only child or had sibling(s), residential location type, city, pregnancy intention, monthly household income (yuan, RMB), gravidity, pregnancy complications, and comorbidities.

Data analysis
To calculate CR during the perinatal period, we utilized a person-oriented approach, using latent class growth curve modeling (LCGM) [22], to classify perinatal women with similar patterns of change in CR across three-time points (i.e.third trimester pregnancy between week 32-35, one week postpartum, and six weeks postpartum).LCGM is useful with longitudinal data to represent heterogeneity in developmental trajectories and considers patterns of intra-individual change [22,23].
Mplus 7.0 and SPSS (version 26.0) were used for data analysis using a significance level of 5%.First, the LCGM was used to identify distinct change patterns and to classify women into unobserved groupings with similar CR patterns.Five latent class growth models were fitted to the longitudinal CR scores with different numbers of groups (1-5 groups).Models were compared based on: Akaike Information Criterion (AIC: the smaller, the better); Bayesian Information Criteria (BIC: the smaller, the better); sample-size adjusted BIC (a-BIC: the smaller, the better); Entropy (ideal are statistics >0.80 and the larger, the better the classification accuracy); and the Vuong-Lo-Mendell Rubin Likelihood Ratio Test (LMR-LRT) and the Bootstrapped Likelihood Ratio Test (BLRT) was used to compare each model with the model containing one fewer classes according to the likelihood ratio (if p < 0.05, the model with k categories is superior to the model with k-1 categories) [22,23].Missing data were handled using full information maximum likelihood, which allowed for the inclusion of all participants who provided at least one observation.
Second, multi-factor logistic regression analysis was conducted to determine whether any of the demographic and clinical variables could predict CR trajectories.Results are shown as odds ratios (ORs) with 95% confidence intervals (CIs).Finally, unconditional binary logistic stepwise regression analysis was used to examine the relationship between CR trajectory groups and PPD.

Sample characteristics
As shown in Figure 1, the sample comprised 344 pregnant women, with 23 participants (6.7%) excluded from the analysis due to induced labor or loss of follow-up.There were no significant differences in sociodemographic and clinical characteristics between our sample of 321 women and the 23 women who were excluded.The descriptive characteristics of the participants are presented in Table 1.For 321 perinatal women, approximately 0.3% at T1, 3.7% at T2, and 24.9% at T3 met the clinical CR cutoff score criterion for high depression risk.Detailed information regarding participation at different time points is shown in Figure 1.

Latent classes of cognitive reactivity trajectories
Table 2 shows the results of the LCGM (linear model, considering the intra-group variance of 0) data analysis.When the number of latent categories is different, the quality of fit of the model is different.Taking CR scores of participants at three different time points as the observation index, 321 eligible participants were included in the model analysis, LCGM was used as the free estimation of time parameters, and 1-5 categories were extracted in turn.When the number of potential categories extracted increased from 1 to 3, the AIC, BIC and a-BIC values all decreased, and when the number of categories increased from 2 to 3, LMR-LRT and BLRT reached a significant level (p < 0.05), and the Entropy was similar.When the number of categories is increased from 3 to 5, the AIC, BIC and a-BIC values all decrease, yielding a very small decrease in amplitude.The p value of BLRT of the four categories models still supports the increase of the number of categories but the Entropy decreases and the significance of LMR-LRT is 0.027.The significance of LMR-LRT of the 5 categories models is greater than 0.05.Based on the above information, the 3-trajectory group (the continuing deterioration group, postpartum deterioration group, and consistent resilient group) solution was further supported by high entropy (0.952) and group assignment probabilities (0.927, 0.993, and 0.993).

Predictors of cognitive reactivity trajectory classification
The results of the logistic regressions indicated that level of education, being an only child, or having gestational complications significantly predicted CR trajectory classification (see Table 3).Specifically, compared to the consistent resilient group, perinatal women with a bachelor's degree or higher (OR ¼ 0.096, 95% CI: 0.013-0.732)and a gestational diabetes diagnosis (OR ¼ 2.269, 95% CI: 1.128-4.564)were more likely to be in the continuing deterioration group.In Model 2, perinatal women who were only children were more likely to be in the postpartum deterioration group (OR ¼ 2.078, 95% CI: 1.044-4.133).

Association of cognitive reactivity subtypes with depression
The logistic regression model showed that after controlling for sociodemographic and clinical characteristics, the CR trajectory groups could explain 33.2% of the variation in PPD (see Table 4).Using the consistent resilient group as the reference, the risk magnitudes of having PPD for the continuing deterioration group and postpartum deterioration group were 5.608 and 2.763 (p < .05),respectively.

Discussion
This is one of the first studies to analyze the developmental trajectory of CR levels in pregnant women during the perinatal period from a dynamic perspective.Combined with the theoretical background of CR and the interpretability of the results, we found three CR trajectory groups and identified their relationship with PPD among pregnant women, from week 32-35 of pregnancy to six weeks postpartum.The findings provide a basis to design more targeted, accurate, and personalized interventions for perinatal women.Furthermore, previously, CR trajectories and their effects on PPD risk have not been studied in perinatal women.
In this study, a large majority of the study participants showed consistent resilient trajectory characteristics, whereas the continuing deterioration group and postpartum deterioration group had similar percentages (percentage of trajectory groups: 17%-22%).The prominence of CR trajectories among perinatal women might be explained by the weakest link hypothesis; that is, various factors induced cognitive susceptibility (e.g.CR) and caused depressive symptoms [24,25].In particular, the women's CR in the continuing deterioration group might be influenced by uncertain childbirth, self-doubt of parenting competence [26], postpartum nutrition [27], and breastfeeding [28].These potential issues can cause these women to be more sensitive to their environments and activate their negative ego schema, thus increasing their CR level.In contrast, the other CR trajectory groups had low or moderate scores at baseline.About 22% of women in the postpartum deterioration group had a significant increase in CR across the perinatal period which may be caused by the risk factors for postpartum posttraumatic stress disorder, such as precipitous delivery or fetal distress during delivery [29], or the experience of obstetric violence during childbirth [30].
While our study's findings align with prior research on the trajectory of affective disorders [30,31], it is important to emphasize the distinct contributions that this study offers to the field.Notably, the CR level of most women in the study were in the consistent resilient group and continued in a stable state over time.
This intriguing trend suggests that a significant portion of perinatal women exhibit consistent and resilient psychological states.As a result, they appear to possess the capacity to effectively manage stressful situations while maintaining a state of calm stability.
In previous longitudinal studies, researchers often treat mean scores of CR from the total group over time as a single linear trajectory, which oversimplifies the complex growth patterns of change.For example, never-depressed individuals with high CR scores predict the first onset of depression within two years [12].Also, individuals with major depressive symptoms are highly associated with negative mood which is usually positively associated with future depression symptoms [32].
This analysis indicates women with a bachelor's degree or higher were more likely to experience a continuing deterioration trajectory.A possible reason is that these women likely have more ability to obtain information about what they are experiencing.With possible mismatched information from various sources in their living environment leading to psychological stress and negative cognitive biases [33].Furthermore, women in the continuing deterioration group were diagnosed more with gestational diabetes mellitus (GDM).GDM provides a possible context for PPD physiologically by inducing disturbances in the hypothalamic-pituitary-adrenal axis, inflammatory changes, and disorders in serotonergic regulation.For instance, both depression and GDM are associated with hypercortisolism, blunted diurnal cortisol rhythms, and hypocortisolism with impaired glucocorticoid sensitivity [34,35].Moreover, in pregnant women, persistent insulin resistance and insulin signaling deficiency appear to be important factors in the long-term reduction of cognitive functions observed following GDM [36].Therefore, women with GDM may experience increases of CR.
An interesting finding of the current study was that women who were only children were more likely to belong to the postpartum deterioration trajectory group.Participants in this study were born during the period of the one-child policy in China (1980China ( -2016) ) and are seen as a generation of "little princesses."These women received more attention, endured higher expectations and external stress than those women who had siblings [37,38] and thus are more likely to be affected by a negative CR during the prenatal period.

Strengths and limitations
The results of the current study provide a novel and informative glimpse into the complex relationship between CR and PPD.We found that the latent CR trajectories prospectively predicted PPD among perinatal women, consistent with previous findings in adolescents [39,40].In other words, the women in the continuing deterioration and postpartum deterioration groups were more likely to have PPD.This finding may be explained by Beck's cognitive theory [41,42], which contends negative cognitions that remain latent in some individuals, even when depressive symptoms are in remission, may be reactivated by life events, stress, or even negative mood states.Our findings provide evidence-based support for facilitating the early screening of women for postpartum depression and the implementation of tailor-made interventions.
This study has some limitations.The CR levels in pregnant women were investigated at three key time points.Compared with high incidence of maternal depression, this study only focused on a relatively short period from week 32-35 of pregnancy to sixweeks postpartum.Studies with a longer follow-up should be carried out to comprehensively examine the developmental trajectory of CR of PPD.In addition,

Conclusion
In this study, three distinct trajectory groups of CR were generated among perinatal women, with 17.2% of participants in the continuing deterioration group, 22.1% in the postpartum deterioration group, and 60.7% in the consistent resilient group.Higher education levels, being an only child in the family, and GDM diagnoses in mothers predicted a greater probability of being in the continuing deterioration or postpartum deterioration groups, which also had higher chances of PPD.This study provides a better understanding of CR and PPD in perinatal women and finds women who belong to the continuing deterioration group or the postpartum deterioration group to be more likely to develop PPD.Our results suggest that healthcare providers should pay more attention to women in these two CR groups and tailor interventions to them in order to decrease PPD.In addition, we recommend that PPD prevention interventions should be designed with a focus on pregnant women with a bachelor's degree or higher, are only children, and those with a GDM diagnosis.

Figure 1 .
Figure 1.Sample flowchart.EPDS: Edinburgh Postnatal Depression Scale.Incomplete: Women not completing all questionnaire contents and dropping out halfway.Refused: Women lost interest in further study and refused to continue cooperating.

Figure 2 .
Figure 2. Three-class trajectory model of cognitive reactivity scores across the period (n ¼ 321).

Table 1 .
Characteristics of the sample by CR grouping.

Table 3 .
Multivariate modeling of predictors of CR trajectory (n ¼ Additionally, the study participants were recruited from one province in Southeast China and the EPDS is not a gold standard assessment for PPD in China.Also, the collected variables were mostly subjective factors which resulted in limited clinical value for this study.Future studies should include standard diagnostic criteria to diagnosis depression and use a licensed psychologist or psychiatrist to confirm PPD.