title: Does risk of preeclampsia differ by twin chorionicity?
abstract: OBJECTIVE
  Examine whether dichorionic (DC) and monochorionic (MC) twins exhibit different rates and severity of preeclampsia.
  
  
  METHODS
  Retrospective cohort study of 695 twin pregnancies from 2002 to 2007. DC pregnancies were compared to MC pregnancies, with the primary outcome of interest being development of preeclampsia, and the secondary outcome being severity of preeclampsia. Chi square test compared proportions and multivariable analyses controlled for potential confounders.
  
  
  RESULTS
  Any preeclampsia developed in 21.1% (104/492) of DC and 10.8% (22/203) of MC pregnancies (p = 0.001), mild preeclampsia in 13.8% (68/492) of DC and 4.9% (10/203) of MC pregnancies (p = 0.001) and severe preeclampsia in 7.3% (36/492) of DC and 5.9% (12/203) of MC pregnancies (p = 0.506). DC pregnancies showed higher odds of mild preeclampsia compared to MC pregnancies (aOR 5.85, 95% CI 1.31-26.13) after controlling for several potential confounders including gestational age at delivery.
  
  
  CONCLUSIONS
  A statistically significant larger proportion of women with DC twins developed any preeclampsia, and specifically mild preeclampsia, compared to those with MC twins. Additionally, after controlling for several potential confounders, women with DC pregnancies demonstrated higher odds of developing mild preeclampsia compared to those with MC pregnancies. Mechanisms of preeclampsia development may differ by twin chorionicity.
authors: Department of Obstetrics & Gynecology, Brigham and Women's Hospital/Massachusetts General Hospital , Boston, MA 02115, USA. tsparks@partners.org
authors: Teresa N
authors: TN
authors: Sparks
authors: Yvonne W
authors: YW
authors: Cheng
authors: Ngoc
authors: N
authors: Phan
authors: Aaron B
authors: AB
authors: Caughey
mesh_terms: D000328:Adult; D002823:Chorion / Q000000981:diagnostic imaging / Q000502:physiology*; D005260:Female; D006801:Humans; D011225:Pre-Eclampsia / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000209:etiology*; D011247:Pregnancy; D059285:Pregnancy, Twin; D012189:Retrospective Studies; D012307:Risk Factors; D014429:Twins, Dizygotic / Q000706:statistics & numerical data; D014430:Twins, Monozygotic / Q000706:statistics & numerical data; D014463:Ultrasonography; D055815:Young Adult