Risk of obstetric anal sphincter injury associated with female genital mutilation/cutting and timing of deinfibulation
Material and methods: In a historical cohort study, nulliparous Somali-born women who had a vaginal birth in the period 1990–2014 were identified by the Medical Birth Registry of Norway and data collected from medical records. Exposures were female genital mutilation/cutting status and deinfibulation before labor, during labor or no deinfibulation. The main outcome was obstetric anal sphincter injuries.
Results: Rates of obstetric anal sphincter injury did not differ significantly by female genital mutilation/cutting status (type 1–2: 10.2%, type 3: 11.3%, none: 15.2% P = 0.17). The total rate of anal sphincter injury was 10.3% compared to 5.0% among nulliparous women in the general Norwegian population. Women who underwent deinfibulation during labor had a lower risk than women who underwent deinfibulation before labor (odds ratio 0.48, 95% confidence interval 0.27–0.86, P = 0.01).
Conclusions: The high rate of anal sphincter injury in Somali nulliparous women was not related to type of female genital mutilation/cutting. Deinfibulation during labor protected against anal sphincter injury, whereas deinfibulation before labor was associated with a doubled risk. Deinfibulation before labor should not be routinely recommended during pregnancy