Kielland's forceps: does it increase the risk of anal sphincter injuries? An observational study.

Introduction and hypothesis Rotational instrumental deliveries are thought to carry additional risks compared with non-rotational instrumental deliveries, including trauma to maternal tissues, and require specific expertise and training. We conducted a retrospective study to investigate the association between the type of forceps delivery and maternal perineal trauma, and in particular to investigate if Kielland’s rotational forceps delivery increases obstetric anal sphincter injuries (OASIS).