Objective To investigate the early diagnosis and treatment of cesarean scar pregnancy（CSP）.Methods Clinical data of 28 patients with CSP in Peking Union Medical College Hospital from January 1994 to April 2007

including age

interval from the last cesarean delivery to diagnosis

clinical presentation

location of the lesion

process of diagnosis and treatment

outcome

and follow-up

were retrospectively analyzed.Results CSP constituted 1.05% of all ectopic pregnancies

and the ratio of CSP to pregnancy was 1∶1221.The mean age of the group was 31.4 years.Twenty-six women had only one prior cesarean delivery.The interval from the last cesarean delivery to diagnosis ranged from 4 months to 15 years.The most common presenting symptoms of CSP were amenorrhoea and vaginal bleeding.Seventeen cases were misdiagnosed as early intrauterine pregnancies and 2 were misdiagnosed as gestational trophoblastic tumor.The other 9 were diagnosed definitely before treatment.The diagnosis was made based on cesarean delivery history

gynecologic examination

ultrasound

and magnetic resonance imaging（MRI）.The treatment of CSP included systemic or local methotrexate administration

conservative surgery

and hysterectomy.The conservative treatment was successful in 24 cases.All of the 28 women were cured through individual therapies.Conclusions CSP is rare and usually misdiagnosed as other diseases.Ultrasound is valuable for diagnosing CSP

and MRI can be used as an adjunct to ultrasound scan.Early diagnosis offers the options of conservative treatment and greatly improves the outcome of patients.Individual therapy is strongly recommended.