Most women give birth spontaneously, but some need assistance during the second stage of labour with obstetric forceps or the vacuum. The rates of instrumental vaginal births range from 5% to 20% of all births in high-income countries, with little information about the incidence in low-income countries. Indications for instrumental vaginal births are generally fetal heart rate abnormalities, poor position of the baby, maternal exhaustion and some maternal medical conditions such as heart disease. The majority of instrumental vaginal births are conducted in the delivery room, but in a small proportion of anticipated difficult births (2% to 5%), a trial of instrumental vaginal birth is conducted in theatre with preparations made for proceeding to caesarean section. It has been suggested that for these anticipated difficult assisted vaginal births, it may be preferable to go straight to caesarean section. The advantage of doing an immediate caesarean section would be a reduced risk of morbidity for both mother and baby from a failed attempted instrumental birth. However, the disadvantages of routinely doing a caesarean section in these circumstances are an increased risk of morbidity from caesarean section which often manifests itself at a subsequent birth. The review of trials looking at attempted instrumental delivery in theatre versus immediate caesarean section for anticipated difficult births identified no trials to help with making this decision. Further research is clearly needed.