Hysteroscopic metroplasty seems the treatment of choice for septate uterus. Little information is available on the possible usefulness of postoperative intrauterine device (IUD) insertion and estrogen administration in preventing fusion of a freshly cut septum and intrauterine adhesion formation. A hysteroscopic incision in a uterine septum was made in 20 women. Postoperatively an IUD was inserted in ten of them and conjugated estrogens administered for 30 days with medroxyprogesterone acetate on days 26-30 (group I); the other ten were given no other therapeutic measures (group II). On follow-up hysterography five women in group I had a normal uterine cavity, and five had a residual fundal notch greater than or equal to 1 cm. In group II four had a normal uterine cavity, and six had a residual fundal notch greater than or equal to 1 cm. No intrauterine adhesions were detected in any of the patients. IUD insertion and hormonal therapy after hysteroscopic metroplasty do not seem to be needed to prevent septal fusion.