One of the most challenging emergencies for obstetricians is obstructed labour, when the cervix (neck of the womb) is fully stretched but the baby will not come out. This may be due to the baby having a head which is too large to pass easily through the mother’s birth canal (disproportion) or to the baby’s head trying to come out the wrong way up (occipitoposterior position - with the mother on her back, the baby is usually born face down). The choice of management is usually between doing a caesarean section (an operation to open the womb through the abdomen and deliver the baby) or using instruments (such as forceps) to pull the head through the cervix. Both options may damage the mother or the baby.
In a study of 393 women with obstructed labour who received standard treatment as judged appropriate by the obstetrician in charge, Deirdre Murphy and colleagues from Bristol, UK, found that women who had caesarean section were about twice as likely to have serious bleeding than women who had delivery by forceps. Babies of mothers who had caesareans were also about twice as likely to need treatment in a neonatal intensive care unit. Instrumental delivery did, however, cause an increased incidence of trauma to the baby: bruising, lacerations, nerve injuries, and, rarely, cerebral bleeding. The authors conclude that unless there is clear evidence of disproportion, “our findings support the use of safe vaginal instrumental delivery for the management of arrested progress.” The study also showed that a favourable outcome for mothers and babies was more likely if the obstetricians in charge were the more experienced.
In most fields of medical and surgical practice the “gold standard” for deciding between alternative treatments is a randomised controlled trial, where patients are allocated at random to one or another treatment. This method removes most sources of bias. Murphy and colleagues admit that ideally the choices of management they examined would be the subject of a randomised controlled trial; however, “to recruit women to studies while they are in labour is thought unethical, and recruitment in the antenatal period could result in women becoming distressed at the possibility of obstructed labour.”
Contact Dr Deirdre J Murphy, Division of Obstetrics and Gynaecology, St Michael’s Hospital, Southwell Street, Bristol BS2 8EG, UK; T) +44 (0)117 921 5411; F) +44 (0)117 928 5290; E) d.j.murphy@bristol.ac.uk
Journal
The Lancet