RESUMEN
OBJECTIVE@#It is uncertain whether preeclampsia (PE) is caused by pre-existing factors or by pregnancy itself. We want to answer this important question in public health by conducting a large pre-conception cohort in China.@*METHODS@#A prospective and pre-conception cohort study with a target recruitment of 5000 couples who plan to have a baby within 6 months was performed and their conception, delivery, and postpartum were followed up in Liuyang county, Hunan Province of P. R. China.@*RESULTS@#A total of 1915 young couples have been recruited into this unique pre-conception cohort till now. In general, both systolic blood pressure and diastolic blood pressure decreased in early second trimester from pre-conception level but increased in third trimester and at delivery.@*CONCLUSION@#The proposed pre-conception cohort study will have important theoretical and practical implications on the prevention of PE and its associated cardiovascular disease risks.