Objective: Microchimerism has been investigated as a possible contributor to the pathophysiology of preeclampsia. Although trisomy 21 is associated with pronounced microchimerism, it has not been connected with an increased risk of preeclampsia. Our objective was to readdress the relationship between preeclampsia and trisomy 21 in a large population.
Methods: Using the Texas Birth Defects Registry for 1999-2003, a cohort of 2995 pregnancies with a trisomy 21 fetus was identified and compared with a control cohort of 1959 pregnancies with fetal isolated oral clefts. Chi-square test was used to estimate the significance of observed difference in the proportion of preeclampsia between groups. The interactive and confounding effects of covariates were examined by stratified analysis and the Mantel-Haenszel method.
Results: We observed 84 cases of preeclampsia in the trisomy 21 cohort (3.7%) and 111 cases in the oral cleft cohort (5.7%). The crude OR for having preeclampsia in relation to trisomy 21 was 0.63 (95% CI 0.47-0.85). The OR estimates remained the same after adjustment for confounders.
Conclusion: Pregnancies carrying a trisomy 21 fetus do not have an increased risk of preeclampsia. Besides epidemiologic significance, our data also have relevance for genetic counseling.