title: Expectant treatment of cesarean scar pregnancy: two case reports and a glimpse at the natural courses.
abstract: OBJECTIVE
  Pregnancy in previous cesarean scar is the rarest form of ectopic pregnancy. Little is known about its natural history and optimal management. All except one reported case in the literature that were treated expectantly either become unsuccessful or complicated. We aimed to present two cases of cesarean scar pregnancy (CSP) that were managed expectantly to discuss the value of this management and have a glimpse of the natural courses of certain CSPs.
  
  
  METHODS
  We present two cases of parous women with complaint of amenorrhea and mild bleeding. Sonography and magnetic resonance imaging (MRI) revealed the diagnosis of CSP without viable gestational sac. The patients opted for expectant treatment. We closely monitored the patients with a detailed plan.
  
  
  RESULTS
  In case 1, the patient had mild bleeding during monitoring and her serum betaHCG dropped quickly to normal range after 7 weeks. She was fully recovered with total absorption of the mixed mass in the scar of the anterior wall of the uterus. In case 2, the patient had laparoscopy after expectant management for 16 weeks because her serum betaHCG reached a plateau between 30 and 40 mIU/mL for 4 weeks and there was no obvious resorption of the mixed mass within the lower anterior wall of the uterus. The histopathology revealed decidualized villa within organizing tissue and the patient recovered uneventfully.
  
  
  CONCLUSIONS
  CSP with no viable gestation sac and rapidly decreased serum betaHCG level can be expectantly treated. The natural history of such CSPs may be naturally demised.
authors.affiliation: Department of Obstetrics and Gynecology, Peking Union Medical College, Chinese Academy of Medical Science, Beijing, China. haiyuanliu@163.com
authors.forename: Haiyuan
authors.initials: H
authors.lastname: Liu
authors.forename: Jinhua
authors.initials: J
authors.lastname: Leng
authors.forename: Honghui
authors.initials: H
authors.lastname: Shi
authors.forename: Jinghe
authors.initials: J
authors.lastname: Lang
mesh_terms: D000028:Abortion, Induced / Q000379:methods; D000328:Adult; D002585:Cesarean Section; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood; D002921:Cicatrix / Q000150:complications*; D005260:Female; D006801:Humans; D010535:Laparoscopy; D008279:Magnetic Resonance Imaging; D011247:Pregnancy; D011271:Pregnancy, Ectopic / Q000175:diagnosis* / Q000628:therapy*; D016896:Treatment Outcome; D016216:Ultrasonography, Prenatal; D057832:Watchful Waiting
chemical_list: D018997:Chorionic Gonadotropin, beta Subunit, Human