The relationship between cervical dilatation at initial presentation in labour and subsequent intervention

Objective To examine the relationship between the cervical dilatation at wh ich women present in labour and the,subsequent likelihood of caesarean sect ion. Design Retrospective cohort studs. Setting University teaching hospital. Population 3220 women met the entry criteria from 14,050 deliveries bem cen January 1995 and December 1999. Methods Women meeting the following criteria were identified: those in spon taneous labour with a singleton pregnancy and a cephalic presentation at 37 -42 weeks of gestation: all women delivering within 36 hours of first prese ntation were included. Women who had spontaneous rupture of the membranes b efore first attendance were excluded. Main outcome measures The primary Outcome was the rate of caesarean section , Secondary outcomes were operative vaginal delivery, fetal weight, cord pH , five minute Apgar score, length of labour, labour augmentation with oxyto cin and epidural analgesia. Results The risk of caesarean section decreased with increasing, cervical d ilatation at presentation, This was true for nulliparous (n = 1168) and par ous omen (n = 2052). The caesarcan section rate of nulliparous women presen ting at 0-3cm (n = 812) was 10.3%. compared with 4.2% for those presenting at 4cm-10cm (n = 356), and the mean duration of labour before presentation as 2.0 hours versus 4.5 hours, respectively (P = 0.0001 For parous women th e caesarean section rates were 5.7% and 1.3% respectively (P = 0.0001). The re were significantly greater frequencies of use of oxytocin and epidural a nalgesia by women presenting earlier in labour. The caesarean section rate of 185 nulliparae (15.8%) who were initially allowed home was no different from those admitted immediately (9.2% vs 8.2%. P = 0.67). Similarly 196 (9. 5%) of multiparae went home and had a caesarean section rate of 3.6% compar ed with 3.1% if admitted immediately (P = 0.76). Conclusions Women who present to hospital at 0-3cm spend less time in labou r before presentation and are more likely to have obstetric intervention th an those presenting in more advanced labour. Outcomes were similar whether or not the woman was initially allowed home.