Background: There is a global concern about the escalating use of labour interventions in low-risk women. Despite the lack of evidence for spontaneous labour, amniotomy is commonly used. However, the prevalence is not known. Information on prevalence and possible differences between hospitals offers opportunity for comparisons, identification of best practice, and clinical improvement.

Aim: To explore the prevalence of amniotomy in Sweden in relation to variations between hospitals and over time.

Methods: This was a retrospective nationwide register-based study, including data from January 2017 to June 2020. Data were collected from the Swedish Pregnancy Register which covers 93% of all births in Sweden. Data were analysed in relation to Robson Group (RG) 1 and 3, using descriptive statistics and chi-square test.

Results: During the study period a total of 330 913 women gave birth, whereof 134 493 (40.6%) underwent amniotomy. The prevalence was significantly higher for RG 1 compared to RG 3, 41.1% vs. 32.3% (p<0.001). In RG 1 and RG 3, the highest prevalence was reported at the hospitals with <1000 births annually, while the lowest prevalence was reported at University hospitals, 42.3% vs. 34.5% (p<0.001). The overall prevalence did not change during the study period (p=0.678), thus, for RG 1 and RG 3, the prevalence of amniotomy decreased from 37.5% to 34.1% (p<0.001).

Conclusions: Amniotomy is a commonly used labour intervention that is used in more than one third of all births in Sweden. Regarding prevalence in RG 1 and RG 3, significant variations between hospitals and a small but significant decrease over time, were observed. However, the overall prevalence remained the same, indicating an increase of amniotomy in other Robson Groups.