Forceps delivery is sometimes necessary during the second stage when the mum gets too exhausted to push further or if there is significant concern about the baby for example fetal distress which requires the baby to be delivered immediately. I tend to choose forceps when I feel the mum is not pushing well enough or baby is big. If mum is pushing well and there is good descent of the baby but mum still need helps eg with rotation of the foetal head, that's when I decide to use a vacuum extractor instead. Assisted delivery if done by a competent practitioner should not result in trauma to the child.
Therefore the decision for assisted delivery versus Caesarean section in the second stage is a very important one and this depends on the experience and competence of the obstetrician, as well as the mum’s preferences. These discussions should ideally be done prior to the birth during the pregnancy check-ups. This is because during the second stage decisions need to be made very quickly or it may be an emergency situation during which an extended discussion regarding pros and cons of assisted delivery versus Caesarean section may not be possible.