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.
Notes
*This study was conducted using data from patients at the University of California at San Francisco. The data was presented in poster format at the 31st Society for Maternal-Fetal Medicine meeting in San Francisco, CA on 11 February 2011 (abstract # 612), as well as in oral format at the New England Perinatal Society meeting in Newport, RI on 13 March 2010.