STRIDER (NZAus): A Randomised Controlled Trial of Sildenafil Therapy In Dismal Prognosis Early-Onset Intrauterine Growth Restriction (New Zealand and Australia)

Severe early-onset intrauterine growth restriction (IUGR) is associated with high rates of death before birth, death in the neonatal period and long term handicap as a consequence of being born so early and so small. We currently have no treatment for this disease other than close monitoring and (if the baby is mature enough and grown sufficiently to have a chance of survival) delivery when monitoring suggests the situation is ‘in extremis’.

The majority of these cases are due to abnormal placental development and poor blood supply to the fetus. Sildenafil, as a vasodilator, has the potential to improve blood supply to the uteroplacental vessels and thus improve supply to the baby and possibly aid fetal growth. Data from a small case-control study suggest some potential benefits in fetal growth associated with sildenafil use in pregnancies with very early onset IUGR where the prognosis was otherwise extremely poor.

The purpose of this double-blind randomised placebo-controlled trial is to assess the effect of sildenafil on fetal growth in similar pregnancies with poor prognosis. The results will be combined with similar planned studies worldwide to assess its impact on the most important outcome of all, neonatal survival free of major handicap.