A randomised trial of timed delivery for the compromised preterm fetus: short term outcomes and Bayesian interpretation

Objectives To compare the effect of delivering early to pre-empt terminal hypoxaemia with delaying for as long as possible to increase maturity. Design A randomised controlled trial. Setting 69 hospitals in 13 European countries. Participants Pregnant women with fetal compromise between 24 and 36 weeks, an umbilical artery Doppler waveform recorded and clinical uncertainty whether immediate delivery was indicated. Methods The interventions were 'immediate delivery' or 'delay until the obstetrician is no longer uncertain'. The data monitoring and analysis were Bayesian. Main outcome measures 'Survival to hospital discharge' and 'developmental quotient at two years of age', this latter to be reported later. Results Of 548 women (588 babies) recruited, outcomes were available on 547 mothers.(587 babies). The median time-to-delivery intervals were 0.9 days in the immediate group and 4.9 days in the delay group. Total deaths prior to discharge were 29 (10%) in the immediate group versus 27 (9%) in the delay group (odds ratio 1.1, 95% CI 0.61-1.8). Total caesarean sections were 249 (91%) in the immediate group versus 217 (79%) in the delay group: (OR 2.7; 95% CI 1.6-4.5). These odds ratios were similar for those randomised at gestational ages above or below 30 weeks. Interpretation The lack of difference in overall mortality suggests that clinicians participating in this trial were on average prepared to randomise at about the correct equivocal threshold between delivery and delay. However, there was insufficient evidence to convince enthusiasts for either immediate or delayed delivery that they were wrong.