Examining the Evidence
GRIT trial: Delayed delivery for growth-restricted fetuses?
To compare 2 interventions for growth-restricted fetuses remote from term: early delivery to preempt intrauterine hypoxia, and delayed delivery for as long as possible to gain maturity.
At 2 years, the overall rate of death or severe disability was 55 (19%) of 290 immediate births and 44 (16%) of 283 delayed births. After adjustment for gestational age and umbilical-artery Doppler category, the odds ratio was 1.1, indicating a trend toward more disability with immediate delivery, and the 95% credibility interval was 0.7 to 1.8.
Optimal timing of delivery in high-risk pregnancies continues to confound obstetricians and perinatologists. This randomized, controlled trial attempts to address the issue in the setting of fetal growth restriction. It involved 548 pregnant women in 13 European countries who had fetal compromise between 24 and 36 weeks of gestation. In all cases, it was uncertain whether immediate delivery was indicated. These women were randomized to immediate delivery (within 48 hours to permit steroid administration) or deferred delivery (until safe delivery could be delayed no longer because of worsening test results or the passage of time). The median interval between randomization and delivery was 0.9 days with immediate delivery and 4.9 days with delayed delivery.
Strengths lie in the trial design, 2-year follow-up of infants, blinded outcomes assessment, and statistical analysis.
Weaknesses include the trial’s multicenter nature, lack of standardization for management interventions, and probable practitioner variability in disability assessment among the 69 hospitals involved.
Unanswered questions. We are not told the degree of growth restriction of the cases enrolled, or whether any misclassification errors occurred.
Decisions regarding route of delivery and intrapartum management were left to the provider’s discretion and were not standardized; this is important because a number of intrapartum events can lead to perinatal morbidity and mortality. Unexplained antepartum fetal death occurred more frequently in the expectantly managed group; the only cases of intrapartum trauma or asphyxia occurred in that group as well.
That said, at 2 years the overall results are similar between the groups. Investigators concluded that, while obstetricians seem to be intervening at the appropriate time, early intervention may not translate into improved outcomes overall.
Absent from the dialogue is the medicolegal risk associated with what some would consider inordinate delay in delivery versus premature intervention. The former generally would have the less favorable medicolegal outcome.
This study fails to definitively identify the optimal intervention in high-risk pregnancies remote from term. Antenatal testing remains imprecise, and fetal demise from delayed intervention must be weighed against the risk of long-term disabilities from intervening too early.
For now, the obstetrician must rely on close fetal surveillance and gestational age as the prime drivers of delivery decisions. It is also crucial that we adequately communicate to patients the potential risks associated with the 2 strategies.