Background Birth trauma may be a risk factor for postpartum post-traumatic stress disorder (PTSD). However, no systematic review on postpartum PTSD in women with traumatic childbirth has been reported. Objective This study aimed to estimate the incidence of PTSD following traumatic childbirth through systematic review and meta-analysis. Search strategy Six databases (CINAHL, PsycINFO, Embase, PubMed, CNKI and Wanfang) were searched from inception to 28 February 2022. Selection criteria Cohort studies and cross-sectional studies related to the incidence of PTSD following traumatic childbirth were included. Data collection and analysis Two reviewers independently conducted studies selection, quality evaluation of studies, and data extraction. The Random-effects meta-analysis was conducted to derive the pooled incidence using Stata 16.0 software. Main results A total of nine studies with 1,823 women experienced traumatic birth were included. Of them, 353 were identified as PTSD. The pooled incidence of PTSD after traumatic childbirth was 19.2% (95%CI: 11.9%~26.5%). Subgroup analyses showed that the incidence of PTSD varied with traumatic birth/PTSD assessment scales and time, and type of study participants. Meta-regression analyses indicated that the study country was a significant source of heterogeneity, and the sample size birth trauma/PTSD were potential predictors of incidence of PTSD after a traumatic birth. Sensitivity analysis by deleting one study at a time yielded similar results. Conclusions The incidence of PTSD in women with traumatic childbirth is about 19%, which is much higher than that in general postpartum population. Keywords post-traumatic stress disorder, incidence, traumatic childbirth, postpartum, meta-analysis

Background Hypothyroxinemia, i.e. Low free T4 with normal TSH level, which overlaps, to a great extent, with the laboratory criteria of central hypothyroidism, could be easily neglected, if attention is paid only to patients with elevated TSH. We aimed to assess the association between mirtazapine use and hypothyroxinemia in patients affected by major depressive disorder. Methods We conducted a retrospective cohort study in the Second Affiliated Hospital of Xinxiang Medical University between January 2016 and December 2018. Patients affected by major depression disorder and admitted to the hospital for treatment during the study period and had thyroid tests at admission and after treatment were included. Patients with abnormal thyroid function at baseline or received mood stabilizers or quetiapine during hospitalization were excluded. Mirtazapine use was the exposure measure, and hypothyroxinemia was as the primary outcome of this study. Log-binomial model was used to estimate the association between mirtazapine use and hypothyroxinemia, after adjusting for potential confounding factors. Results A total of 220 eligible patients were included in the final analysis. Of them, 88 used mirtazapine. The incidence of hypothyroxinemia in patients who used mirtazapine was higher (37.5%) than those patients who did not use (19.7%). The relative risk of developing hypothyroxinemia was 1.64 (95% confidence interval: 1.31-1.78) for mirtazapine use, after adjusting for confounding factors. Conclusion Mirtazapine use was associated with the risk of developing hypothyroxinemia. Clinicians should be aware that hypothyroxinemia may be neglected in patients treated by mirtazapine due to attention paid only to those with elevated TSH.