The only prostaglandin analogue licensed in Italy for induction of labour in spontaneous and therapeutic abortion is gemeprost. The authors report a case of spontaneous uterine rupture of a scarred uterus, for previous caesarean sections, in a woman at 20 weeks of gestation with a diagnosis of spontaneous abortion. She received a pessary of gemeprost every three hours. After the fifth pessary, she complained of severe pain. At the ultrasound examination, uterine cavity appeared empty and the dead fetus was dislocated in the abdomen. Emergency laparotomy was performed and uterine tear was repaired. To induce labour for fetal demise or therapeutic abortion in second trimester in women with scarred uterus, the authors decided to lengthen the time between administrations of pessary from four to five hours depending on patient’s symptoms. However the appropriate drug regimen has still to be found and more data are necessary.