Introduction and hypothesis: The use of Kielland's rotational forceps is considered to involve greater technical difficulty and may be associated with a higher rate of pelvic floor trauma. Our main objective was to evaluate the association between avulsion of the levator muscle and rotational and non-rotational forceps.
Methods: This was an observational study carried out at a tertiary hospital that recruited singleton cephalic vaginally primiparous women with previous Kielland's forceps delivery between March 2012 and May 2017. Patients were retrieved from a local database, contacted consecutively and blinded to all clinical data. Power calculations determined a sample of n = 160 patients. All women underwent a urogynecological interview, clinical examination and 4D translabial ultrasound (TLUS). The 4D TLUS volumes were stored and analyzed offline by an experienced ultrasound examiner who was blinded to all clinical data.
Results: A total of 165 patients were available for analysis. Rotational forceps accounted for 27.3% (45 out of 165) of the study sample. Avulsion was present in 41.8% (69 out of 165) of all forceps deliveries. On multivariate analysis, rotational forceps was associated with avulsion, with an adjusted odds ratio (OR) of 2.57 (CI 95% 1.20-5.62, p = 0.016). Body mass index at the beginning of gestation was found to be a protective factor, with an adjusted OR of 0.918 (CI 95% 0.847-0.986, p = 0.025).
Conclusion: Rotational forceps is associated with a higher avulsion rate than non-rotational forceps, with an adjusted OR of over 2.5. Obstetricians need to consider the potential long-term consequences of performing a rotational forceps for mothers.
Keywords: Avulsion; Kielland forceps; Rotational forceps.
© 2021. The International Urogynecological Association.