Lay summary
There is no treatment for intrauterine growth restriction (IUGR) other than delivery once a baby gets sick. Being born premature and growth restricted may result in short and long term health problems. The aim of this trial is to determine whether a novel treatment (sildenafil) will increase fetal growth velocity allowing delay in delivery which may improve survival and reduce complications that lead to handicap and disease. This randomised placebo controlled trial will recruit women from specialised clinics across New Zealand and Australia. Women with very small babies