Immediate or delayed birth for a preterm fetus with suspected compromise

What is the issue?

For a fetus who is not receiving enough oxygen or nutrients, the choice is to deliver the baby immediately (following a course of steroids to help the baby’s lungs to mature) or to wait as long as is thought to be safe. This review looked at which option was better for mothers and babies.

Why is this important?

Waiting allows the baby to develop as much as possible and decreases the risks associated with being premature. Premature babies are more likely to have breathing difficulties, low body temperature, low blood sugar levels, infection and jaundice. Remaining in the womb may mean the baby's vital organs are affected by a lack of oxygen.

What evidence did we find?

We searched for evidence on 30 April 2016. This review includes one randomised study with 548 pregnant women (and 588 babies) with pregnancies between 24 and 36 weeks' gestation. The study took place in 13 countries in Europe, between 1993 and 2001. Women were asked to take part if their doctor was concerned about the baby but unsure if immediate delivery was best. The women were randomly allocated to immediate delivery or delivery when the doctor thought it was necessary. There were a few problems with the design of the study which may have affected the results: women and doctors knew which group they were in, some families left the study, and twins were analysed as though they were unrelated babies. There was moderate-quality evidence for the main outcomes. Women only took part in the study if their doctor was not sure whether the baby needed to be born immediately or not. We do not know if the results apply when the doctor thinks that immediate birth or waiting was needed.

Most babies in the delayed delivery group stayed in the womb for four days longer than babies in the immediate delivery group. More women in the immediate delivery group had a caesarean section (high quality evidence) and more babies delivered immediately needed mechanical breathing support for longer than 24 hours. There was no clear difference between immediate and delayed delivery in the number of babies who died (around the time of birth, or in the days and months after) (moderate quality evidence). There was also no clear difference in the number of babies who showed signs of medical problems known to affect premature babies, such as bleeding in the brain. The number of children with cerebral palsy at age two was higher in the immediate delivery group but there was no difference in neurodevelopmental impairment at or after two years, death or disability at two years (moderate quality evidence), and death or disability in childhood (six to 13 years). Some important outcomes were not reported, such as going to the neonatal intensive care unit and breathing problems. We were not able to add up the number of babies with different illnesses to work out the total number of babies with an illness, as some babies might be counted more than once.

What does this mean?

For preterm babies with suspected compromise and uncertainty about whether to deliver or not, there appears to be no benefit to immediate delivery.

As there is only one trial, and it has flaws, we need to be careful how we apply this evidence. We still do not know how long it is best to wait, and if waiting is better at some gestational ages or for certain conditions causing compromise. Better methods for diagnosing problems may also help us to decide when it is best for the baby to be born.

Delayed delivery may be better for mothers and babies, but further large trials are needed to check if it makes a difference to rare outcomes, such as the number of babies who die. Future trials should be high quality and report all important outcomes.

Authors' conclusions: 

Currently there is insufficient evidence on the benefits and harms of immediate delivery compared with deferred delivery in cases of suspected fetal compromise at preterm gestations to make firm recommendations. There is a lack of trials addressing this question, and limitations of the one included trial means that caution must be used in interpreting and generalising the findings. More research is needed to guide clinical practice.

Although the included trial is relatively large, it has insufficient power to detect differences in neonatal mortality. It did not report any maternal outcomes other than mode of delivery, or evaluate maternal satisfaction or economic outcomes. The applicability of the findings is limited by several factors: Women with a wide range of obstetric complications and gestational ages were included, and subgroup analysis is currently limited. Advances in Doppler assessment techniques may diagnose severe compromise more accurately and help make decisions about the timing of delivery. The potential benefits of deferring delivery for longer or shorter periods cannot be presumed.

Where there is uncertainty whether or not to deliver a preterm fetus with suspected fetal compromise, there seems to be no benefit to immediate delivery. Deferring delivery until test results worsen or increasing gestation favours delivery may improve the outcomes for mother and baby.

There is a need for high-quality randomised controlled trials comparing immediate and deferred delivery where there is suspected fetal compromise at preterm gestations to guide clinical practice. Future trials should report all important outcomes, and should be adequately powered to detect differences in maternal and neonatal morbidity and mortality.

Read the full abstract...
Background: 

Immediate delivery of the preterm fetus with suspected compromise may decrease the risk of damage due to intrauterine hypoxia. However, it may also increase the risks of prematurity.

Objectives: 

To assess the effects of immediate versus deferred delivery of preterm babies with suspected fetal compromise on neonatal, maternal and long-term outcomes.

Search strategy: 

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 April 2016) and reference lists of retrieved studies.

Selection criteria: 

Randomised trials comparing a policy of immediate delivery with deferred delivery or expectant management in preterm fetuses with suspected in utero compromise. Quasi-randomised trials and trials employing a cluster-randomised design were eligible for inclusion but none were identified.

Data collection and analysis: 

Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy.

Main results: 

We included one trial of 548 women (588 babies) in the review. Women with pregnancies between 24 and 36 weeks' gestation took part. The study took place in 13 European countries, between 1993 and 2001. The difference in the median randomisation to delivery interval between immediate delivery and deferred delivery was four days (median: 0.9 (inter-quartile range (IQR) 0.4 to 1.3) days for immediate delivery, median: 4.9 (IQR 2.0 to 10.8) days in the delay group).

There was no clear difference in the primary outcomes of extended perinatal mortality (risk ratio (RR) 1.17, 95% confidence interval (CI) 0.67 to 2.04, one trial, 587 babies, moderate-quality evidence) or the composite outcome of death or disability at or after two years of age (RR 1.22, 95% CI 0.85 to 1.75, one trial, 573 babies, moderate-quality evidence) with immediate delivery compared to deferred delivery. The results for these outcomes are consistent with both appreciable benefit and harm. More babies in the immediate delivery group were ventilated for more than 24 hours (RR 1.54, 95% CI 1.20 to 1.97, one trial, 576 babies). There were no differences between the immediate delivery and deferred delivery groups in any other infant mortality outcome (stillbirth, neonatal mortality, postneonatal mortality > 28 days to discharge), individual neonatal morbidity or markers of neonatal morbidity (cord pH less than 7.00, Apgar less than seven at five minutes, convulsions, interventricular haemorrhage or germinal matrix haemorrhage, necrotising enterocolitis and periventricular leucomalacia or ventriculomegaly).

Some important outcomes were not reported, in particular infant admission to neonatal intensive care or special care facility, and respiratory distress syndrome. We were not able to calculate composite rates of serious neonatal morbidity, even though individual morbidities were reported, due to the risk of double counting infants with more than one morbidity.

More children in the immediate delivery group had cerebral palsy at or after two years of age (RR 5.88, 95% CI 1.33 to 26.02, one trial, 507 children). There were, however, no differences in neurodevelopment impairment at or after two years (RR 1.72, 95% CI 0.86 to 3.41, one trial, 507 children), death at or after two years of age (RR 1.04, 95% CI 0.66 to 1.63, one trial, 573 children), or death or disability in childhood (six to 13 years of age) (RR 0.82, 95% CI 0.48 to 1.40, one trial, 302 children). More women in the immediate delivery group had caesarean delivery than in the deferred delivery group (RR 1.15, 95% CI 1.07 to 1.24, one trial, 547 women, high-quality evidence). Data were not available on any other maternal outcomes.

There were several methodological weaknesses in the included study, and the level of evidence for the primary outcomes was graded high for caesarean section and moderate for extended perinatal mortality and death or disability at or after two years. The evidence was downgraded because the CIs for these outcomes were wide, and were consistent with both appreciable benefit and harm. Bias may have been introduced by several factors: blinding was not possible due to the nature of the intervention, data for childhood follow-up were incomplete due to attrition, and no adjustment was made in the analysis for the non-independence of babies from multiple pregnancies (39 out of 548 pregnancies). This study only included cases of suspected fetal compromise where there was uncertainty whether immediate delivery was indicated, thus results must be interpreted with caution.

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