Prognostic factors for wound complications after childbirth-related perineal trauma: A systematic review and meta-analysis

Introduction: Although childbirth-related perineal trauma affects the majority of women after vaginal birth, very few healthcare resources are allocated to reducing morbidity from perineal trauma. Wound complications are frequent after perineal trauma has been sustained; however, we know little about which factors are predictive of developing a wound issue. To target possible interventions effectively, it is crucial that those at higher risk are identified. Here, we perform a systematic review and meta-analysis of prognostic factors for sustaining wound complications after childbirth-related perineal trauma. Material and Methods: Medline, Embase, Web of Science, and CINAHL were searched from inception to December 2024 using relevant search terms. There were no restrictions on language or year of publication. Observational studies that investigated two or more potential prognostic factors for wound complications after childbirth related-perineal trauma, where adjusted risks were calculated, were eligible for inclusion. We included all types of tears, sustained through spontaneous or assisted vaginal birth. Meta-analysis was performed where five or more studies investigated a particular prognostic factor for perineal wound complications. Odds ratios (ORs) were pooled using a random effects model. The review was prospectively registered in PROSPERO (CRD42023458738). Results: Fifteen studies were eligible for inclusion, involving 71409 women. Studies included were published between 2006 and 2024 across six different countries. Assisted vaginal birth (10 studies, 65 375 women: OR 2.77, 95% confidence interval [CI] 1.89–4.06) was a significant risk factor for wound complication. Raised body mass index (six studies, 64 770 women: OR 1.33, 95% CI 0.56–3.18) was not a significant risk factor. Prolonged second stage of labor, smoking, and episiotomy were each investigated in three primary studies; therefore, data was insufficient for meta-analysis; however, individual studies indicated that there might be an association with perineal wound complication. Conclusions: Assisted vaginal birth is a significant risk factor for perineal wound complication after childbirth-related perineal trauma. Overall, there are limited studies investigating prognostic factors for perineal wound complication after childbirth related-perineal trauma. Whilst we highlight potential prognostic factors, we recommend that a robust, well-powered primary research study with clearly defined wound complication outcomes and prognostic factors is needed.