title: Pre-eclampsia (PE) and Chorionicity in Women with Twin Gestations.
abstract: BACKGROUND
  Pre-Eclampsia (PE) affects 6-31% of pregnant women with multiple gestations. There are conflicting reports on the association of PE with Chorionicity and zygosity; however, there is a lack of information on this potential association in a population of pregnant Asian Indian women.
  
  
  OBJECTIVE
  To determine as to whether chorionicity and zygosity were associated with PE in a population of Asian Indian women with twin gestations.
  
  
  METHODS
  A retrospective observational study was done at a single tertiary care centre in Southern India.
  
  
  METHODS
  The study included pregnant women with twin gestations, who was delivered at the study institute in 2012. Hypertension in pregnancy was categorized, based on the criteria of the International Society for the Study of Hypertension in Pregnancy. Chorionicity was determined by using ultrasonography and zygosity was determined, based on clinical criteria. Point estimates and the 95% Confidence Intervals (CI) around point estimates of PE and associations of chorionicity and zygosity with PE were determined by using bivariate analysis, logistic regression models and area under Receiver Operator Characteristic (ROC) curves.
  
  
  RESULTS
  This study included 208 women with twin gestations. The incidence of PE in dichorionic twin gestations was 13.17% (n=22, 95% CI: 8.66, 18.96), it was 4.87% (n=2, 95% CI: 0.83, 15.19) in monochorionic twin gestations, it was 16.36% (n=9, 95% CI: 8.29, 27.91) in dizygous twin gestations and it was 4.88% (n=2, 95% CI: 0.83, 15.19) in monozygous twin gestations. Neither chorionicity (adjusted OR: 2.59, 95% CI: 0.55, 12.19) nor zygosity (adjusted OR 2.72, 95% CI: 0.49, 15.13) were associated with PE In a multivariate logistic regression model.
  
  
  CONCLUSIONS
  Although it was not statistically significant, the clinical incidence of PE was higher in dichorionic and dizygous twin gestations.
authors.affiliation: Consultant, Department of Obstetric Medicine, Multiple Pregnancy Unit, Fernandez Hospital Pvt Ltd , Hyderabad, India .
authors.forename: Anupama
authors.initials: A
authors.lastname: Singh
authors.affiliation: Fellow, Department of Obstetric Medicine, High Risk Pregnancy, Fernandez Hospital Pvt Ltd , Hyderabad, India .
authors.forename: Arati
authors.initials: A
authors.lastname: Singh
authors.affiliation: Head, Department of Obstetric Medicine, Fernandez Hospital Pvt Ltd , Hyderabad, India .
authors.forename: Tarakeswari
authors.initials: T
authors.lastname: Surapaneni
authors.affiliation: Head, Department of Obstetric Medicine, Woman and Child Health Research Unit, Fernandez Hospital Pvt Ltd , Hyderabad, India .
authors.forename: Praveen Kumar
authors.initials: PK
authors.lastname: Nirmalan
keywords: Chorionicity; Hypertension; Pre-eclampsia; Twin gestation; Zygosity