Silastic cup vacuum extractor or forceps: a comparative study.

A retrospective analysis over a 2-year period was carried out to compare the limitations in the use of the Silastic Cup vacuum extractor and forceps as the preferred instrument for operative vaginal delivery. Whilst the use of the vacuum extractor was associated with less maternal morbidity (54.9% episiotomy rate; 20.9% nil analgesia) and comparable neonatal problems, an increased failure rate (6.5%) was demonstrated in comparison to forceps delivery (0.7% failed vaginal delivery rate). A comparison of their use for rotational vaginal delivery failed to reveal any significant difference in maternal or neonatal outcome apart from an increased failure rate (30%) to complete vaginal delivery after application of the vacuum extractor. It is concluded that the vacuum extractor is a comparable instrument for midcavity or lift-out instrumental delivery but Kielland's forceps may still be a more appropriate instrument for rotational vaginal delivery.