The association between social support and postpartum post-traumatic stress disorder | BMC Pregnancy and Childbirth

Study design and study population

This prospective cohort study was performed at a tertiary teaching hospital specializing in maternal and child health in Guangdong, China between November 2022 and April 2023. The study recruited mothers who aged 18 years or older and had given birth to a single full-term live birth infant at 3 days postpartum.

Mothers were excluded if they had: (1) a history of trauma leading to PTSD (e.g., experience traumatic events such as earthquakes, traffic accidents, physical assault, childbirth and leading to PTSD); (2) a history of or current of psychiatric disorders (e.g., anxiety, depression, schizophrenia); (3) severe obstetric complications (e.g., amniotic fluid embolism and postpartum hemorrhage); or (4) adverse neonatal outcomes (e.g., admission to neonatal intensive care unit and neonatal asphyxia). Medical information was obtained from both the electronic health record system and mothers’ self-reports. All eligible mothers provided written informed consent before participating in the study. Approval was obtained from the Research Ethics Committee of the study hospital (FSFY-MED-2022-102) prior to commencing the study.

Collection of demographics, clinical, and social support data

A self-administered questionnaire was used to collect demographic and clinical data from the study participants in the obstetric ward at 3 days postpartum, based on self-report and records. Demographic information included maternal age, education, employment status, marital status, and monthly household income per capita. Clinical data included gestational age, parity, mode of delivery, premature rupture of membranes, infant sex, birth weight, early contact, early suckling, rooming-in, and mode of feeding.

The Social Support Rating Scale (SSRS) was used to measure social support among mothers 3 days after childbirth. The SSRS developed by Xiao [25] reflects the unique environmental and cultural conditions in China and is applicable to individuals aged 14 aged and older in the general population. This scale consists of 10 items, with three dimensions: subjective support (4 items), objective support (3 items), and support availability (3 items). Subjective support reflects an individual’s level of satisfaction with being respected, supported, and understood; objective support reflects the extent of practical support available from one’s social network; and support availability evaluates the availability and effectiveness of social support in dealing with life events [22]. Items 1–4 and 8–10 are scored on a range of 1 to 4, item 5 is scored on a range of 5 to 20, and items 6 and 7 are scored on a range of 0 to 9. The total scale scores range from 12 to 66, with higher scores indicating greater social support and more diverse social networks (e.g., family, friends, neighbors, marriage, and organizations). The SSRS has been widely used in China and has shown high reliability and validity [26, 27].

Measurement of postpartum PTSD

At 42 days postpartum, mothers were assessed for PTSD using the 14-item Perinatal Post-Traumatic Stress Disorder Questionnaire (PPQ) [28]. This standardized self-report rating scale is based on the criteria outlined in the Diagnostic and Statistical Manual of Mental Disorders – Fourth Edition and aims to identify mothers suffering PTSD symptoms within 1 to 18 months postpartum. The PPQ measures the key symptoms of PTSD, including re-experience, avoidance, and hyperarousal. Mothers were asked to indicate the degree to which they experienced each symptom in relation to their recent delivery experiences within the past month, with responses ranging from 1 (not at all) to 4 (often for more than 1 month). A total symptom severity score ranging from 0 to 56 was derived by summing the scores from all items, with higher scores indicating more severe PTSD symptoms. A cut-off threshold of 19 or higher was selected as the optimal point to identify probable PTSD [6, 11, 29]. The Chinese version of the PPQ has shown good internal consistency and test-retest reliability, as well as adequate content and construct validity [30]. Considering that the PPQ evaluates PTSD symptoms in the past month, and existing research indicates that the highest prevalence of PTSD occurs at four to six weeks postpartum [31, 32], we decided to conduct a follow-up with participants at 42 days postpartum. This time point also aligns with the route postpartum follow-up for mothers as per the maternal and child healthcare policy in China, providing convenience for these mothers and ensuring the cost efficiency for the research.

Data analysis

Statistical analyses were performed using the Statistical Package for the Social Sciences (SPSS 26.0) and R 4.2.2 software. Descriptive statistics were employed to summarize the demographic and clinical characteristics of the mothers. A two-tailed t-test was conducted to compare the levels of social support between mothers with and without PTSD, with a significance level of P < 0.05.

Multiple linear regression analysis was constructed to determine whether social support (the independent variable) was associated with PTSD (the dependent variable) after adjusting for potential confounders. Confounders and social support were entered in a sequential manner, beginning with the potential confounders and followed by social support. The coefficient of determination R², change in R², and the significance level of the F statistic were reported for regression model fit to the data.

Multiple log-binomial regression analysis was performed to assess the independent association of social support with postpartum PTSD. In this model, the SSRS scores were categorized into quartiles or halves, with the lowest quartile or lower half as the reference group. Estimated effects were expressed as relative risk (RR) with 95% confidence interval (CI). In all analyses, overall social support and its three dimensions were considered separately.

Confounders included in the linear regression and log-binomial regression models were selected based on prior knowledge and literature. The selected confounders included education (high school or below / diploma / bachelor degree or above), monthly household income per capita (< 5,000 RMB, 5,000–8,000 RMB, > 8,000 RMB), parity (primiparous or multiparous), mode of delivery (vaginal or cesarean), and mode of feeding (exclusive breastfeeding, partial breastfeeding, or exclusive formula feeding).