title: Ovarian torsion and spontaneous ovarian hyperstimulation syndrome in a twin pregnancy: A case report.
abstract: BACKGROUND
  Ovarian hyperstimulation syndrome (OHSS) is extremely rare in spontaneous pregnancies. Spontaneous OHSS can result from glycoprotein hormones stimulating follicle-stimulating hormone receptors (FSHR).
  
  
  METHODS
  We report a twin pregnancy in which ovarian torsion and hemoperitoneum complicating OHSS were treated with left adnexectomy and aspiration. The only trigger for spontaneous OHSS in this case was high levels of chorionic gonadotropin hormone.
  
  
  CONCLUSIONS
  Multiple pregnancy, gestational trophoblastic disease, primary hypothyroidism, thyroid-stimulating hormone/gonadotropin-secreting adenomas, and mutations of the FSHR gene may trigger spontaneous OHSS.
  
  
  CONCLUSIONS
  Spontaneous OHSS should be included in the differential diagnosis of acute abdomen in pregnant women; if spontaneous OHSS is diagnosed, the etiology should be determined in order to focus the treatment and avoid future complications.
authors.affiliation: Department of Obstetrics and Gynecology, Corporació Sanitària Parc Taulí, Parc Tauli, 1, 08208 Sabadell, Spain. Electronic address: nuriagilnavarro43@gmail.com.
authors.forename: Núria
authors.initials: N
authors.lastname: Gil Navarro
authors.affiliation: Department of Obstetrics and Gynecology, Corporació Sanitària Parc Taulí, Parc Tauli, 1, 08208 Sabadell, Spain.
authors.forename: Emma
authors.initials: E
authors.lastname: Garcia Grau
authors.affiliation: Department of Obstetrics and Gynecology, Corporació Sanitària Parc Taulí, Parc Tauli, 1, 08208 Sabadell, Spain.
authors.forename: Sílvia
authors.initials: S
authors.lastname: Pina Pérez
authors.affiliation: Department of Obstetrics and Gynecology, Corporació Sanitària Parc Taulí, Parc Tauli, 1, 08208 Sabadell, Spain.
authors.forename: Laia
authors.initials: L
authors.lastname: Ribot Luna
keywords: Case report; Hemoperitoneum; Laparoscopic adnexectomy; Spontaneous ovarian hyperstimulation syndrome; Twin pregnancy