Introduction: Rates of episiotomy and severe perineal tears (SPT) are indicators of the quality of obstetric care. Time-trends in the reported occurrence of episiotomy and SPT can contribute to understand both, changes in care and in the frequency of risk factors. Therefore, we aimed to estimate time trends in the frequency of SPT in Portugal and its relationship with episiotomy.
Methods: We conducted a nationwide register-based study using data from the national inpatient database of all Portuguese public hospitals between 2000 and 2015. Time-trend analysis using joinpoint regression models was performed to identify trends (joinpoints) and compare time changes in the prevalence of SPT and risk factors expressed as annual percentage changes (APC) with 95% Confidence Intervals (95% CI). Poisson regression models were fitted to estimate whether time-trends in SPT rates were explained by changes in risk factors and to assess the association between episiotomy and SPT. Adjusted relative risk (aRR) and their respective 95% CI were obtained.
Results: From 908,999 singleton vaginal deliveries, 20.6% were instrumental deliveries, 76.7% with episiotomy and 0.56% were complicated by SPT. Among women with non-instrumental deliveries and no episiotomy SPT decreased from 2009 onwards (1.3% to 0.7%), whereas SPT kept increasing in women with episiotomy for both non-instrumental (0.1% in 2000 to 0.4% in 2015) and instrumental deliveries (0.7% in 2005 to 2.3% in 2015). Time-trends in potential risk factors did not explain the observed increase in SPT. Episiotomy was associated with a decrease in SPT with adjusted RR varying between 2000 and 2015 from 0.18 (95%CI:0.13-0.25) to 0.59 (95%CI:0.44-0.79) for non-instrumental deliveries and from 0.45 (95%CI:0.25-0.81) to 0.50 (95%CI:0.40-0.72) for instrumental deliveries.
Conclusions: Our findings suggest that episiotomy rate could safely further decrease as the main factor driving SPT rates seems to be an increase in awareness and reporting of SPT particularly among women who underwent an episiotomy.
Keywords: Episiotomy; Obstetric intervention; Severe perineal tears; Time-trends; Women’s health.
© 2022. The Author(s).