Objective: To describe the action of prenatal dexamethasone (PreDex) on the anatomy of female congenital adrenal hyperplasia (CAH) genitalia when started at later stages of gestation.Materials And Methods: Our group follows a large cohort of French CAH patients who underwent PreDex therapy, of whom 258 were recently reported. Four 46,XX patients with a delayed PreDex treatment presented with a virilized genitalia and required surgical reconstruction. This is a retrospective report on genital phenotyping at the time of surgery of these four patients who began PreDex therapy at 8, 12, 20, and 28 weeks of gestation.Results: Although this series is limited in number, the anatomical description of the length of the genital tubercle, the height of the urethra-vaginal confluence, and the degree of fusion of the genital folds seems to be dependent upon the starting date of PreDex. Most PreDex treatments prescribed up to now have covered the full duration of gestation.Conclusions: Our findings suggest that PreDex therapy could be limited to the period of the partitioning window. It is hoped that further prospective multicentric clinical studies will obtain ethical approval in order to elucidate the place and protocols of PreDex therapy in the management of CAH.