Local Oestrogen Versus Placebo as Preoperative Treatment in Patients With Severe Hypospadias: Effects on Post-operative Complications

Inclusion Criteria: * Severe hypospadias with a division of the corpus spongiosum behind the midshaft of the penis and for which repair requires a urethral substitution by onlay urethroplasty. * Subjects operated between 9 and 36 months old. * Subjects operated in one of the departments of paediatric urology involved in the study. * Surgery performed by a surgeon with at least 5 years of practical experience in the hypospadias surgery. * Written informed consent obtained from parents or legal guardians prior to the participation to the study * All hypospadias aetiology (hormonal, karyotype or genetic) Exclusion Criteria: * Refusal to participate * Subjects with glandular hypospadias * Subjects aged \<9 months or \> 36months old at time of surgery. * Subjects who had prior surgery of penis (circumcision or hypospadias surgery) * Subjects treated with androgens (Human Chorionic Gonadotrophin or delayed testosterone) within 6 months prior to surgery. * Intolerance to promestriene or its excipients. * Not affiliated to a healthy or social security cover. * Known tumoral risk * Pure or mixed gonadal dysgenesis (45, X0/46,XY)