Background Although delivery is widely used for preterm babies failing to thrive in utero, the effect of altering delivery timing has never been assessed in a randomised controlled trial. We aimed to compare the effect of delivering early with delaying birth for as long as possible.Methods 548 pregnant women were recruited by 69 hospitals in 13 European countries. Participants had fetal compromise between 24 and 36) weeks, an umbilical-artery doppler waveform recorded, and clinical uncertainty about whether immediate delivery was indicated. Before birth, 588 babies were randomly assigned to immediate delivery (n=296) or delayed delivery until the obstetrician was no longer uncertain (n=292). The main outcome was death or disability at or beyond 2 years of age. Disability was defined as a Griffiths developmental quotient of 70 or less or the presence of motor or perceptual severe disability. Analysis was by intention-to-treat. This trial has been assigned the International Standard Randomised Controlled Trial Number ISRCTN41358726.Findings Primary outcomes were available on 290 (98%) immediate and 283 (97%) deferred deliveries. Overall rate of death or severe disability at 2 years was 55 (19%) of 290 immediate births, and 44 (16%) of 283 delayed births. With adjustment for gestational age and umbilical-artery doppler category, the odds ratio (95% CrI) was 1.1 (0.7-1.8). Most of the observed difference was in disability in babies younger than 31 weeks of gestation at randomisation: 14 (13%) immediate versus five (5%) delayed deliveries. No important differences in the median Griffiths developmental quotient in survivors was seen.Interpretation The lack of difference in mortality suggests that obstetricians are delivering sick preterm. babies at about the correct moment to minimise mortality. However, they could be delivering too early to minimise brain damage. These results do not lend support to the idea that obstetricians can deliver before terminal hypoxaemia to improve brain development.

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.