Decreasing the incidence of anal sphincter tears in instrumental delivery in Hudiksvall, Sweden.

PURPOSE: The primary aim of this study was to observe the change in obstetric anal sphincter tear rates in instrumental deliveries during one decade. Secondly, the changes in non-instrumental deliveries were followed.

METHODS

Data from all deliveries at Hudiksvall Hospital, Sweden 2010-2011 and 2016-2017 were collected. The change of OASIS rate during instrumental deliveries was the most important. Statistical significances were calculated by using chi-square test, test for relative proportions, and Students t-test, where appropriate.

RESULTS

The total incidence of OASIS decreased significantly (from 2.54% to 0.73%, p < .001). Even the OASIS rate in instrumental deliveries decreased substantially from 15.1% to 3.0% (p = .002) but the decrease was statistically insignificant in spontaneous deliveries (from 1.22% to 0.60%, p = .065).

CONCLUSION

Based on the results of our study the manual protection of the perineum reduces the risk of OASIS in instrumental delivery significantly.