Data synthesis and analysis
The analysis was conducted using Stata16.0 software. Heterogeneity
across studies was assessed using the Chi² test (significance set atP < 0.1) and the I² statistic ( I²statistic < 25% was considered a low level of heterogeneity,
25% to 50% a moderate level, and > 50% a high level). IfP > 0.1 and I² ≤50%, the fixed effect model
was selected for statistical analysis, while P ≤ 0.1 andI² >50%, the random effect model was selected for statistical
analysis. Subgroup analyses were performed to explore the sources of
heterogeneity, and meta-regression was further conducted to examine the
impact of potential covariates on the effect size. The effect size was
the incidence of postpartum PTSD after traumatic birth. Then,
sensitivity analysis by removing one study at a time was conducted to
explore the stability of the results. Finally, publication bias was
assessed by Egger’s test. For all analyses, p values <
0.05 were deemed as statistically significant.