The STRIDER trial: one step forward, one step back.23 Feb 2018
Severe, early onset fetal growth restriction (FGR) is characterised by a fetus presenting at a gestational age at the borderline of viability which is extremely small for gestational age by ultrasonic biometry and exhibits other signs of utero-placental insufficiency, such as abnormal patterns of uterine or umbilical blood flow. Following diagnosis, there is, currently, no disease modifying therapy other than medically indicated delivery, which carries a high risk of neonatal death or, if the infant survives, severe neurodisability in later life. Conversely, expectant management carries a substantial risk of intra-uterine fetal death. Balancing these conflicting risks is a day to day element of practice in Maternal-Fetal Medicine. Practitioners looks to a future of disease modifying therapies other than delivery. Unfortunately, the STRIDER trial suggests that one of the promising candidates, sildenafil citrate, is very unlikely to offer hope in this dismal situation. The study was powered to detect a 7 day prolongation in pregnancy. In reality, the trend was towards a reduction in the duration of pregnancy and the 95% confidence interval indicates that the best one could expect is a 1.3 day prolongation. In reality, it is more likely that the drug hastens delivery rather than postpones it.