1. Preconception blood pressure and risk of preterm birth: a large historical cohort study in a Chinese rural population 
Ying Yang, Ph.D., Yuan He, Ph.D., Qian Li, M.S., Yuanyuan Wang, Ph.D., Zuoqi Peng, M.D., Jihong Xu, Ph.D., Xu Ma, M.S. 
Fertility and Sterility 
Volume 104, Issue 1, Pages (July 2015)
DOI: /j.fertnstert
Copyright © 2015 American Society for Reproductive Medicine Terms and Conditions

2. Figure 1
Flowchart of participant recruitment, and derivation of the population used in the final analysis.
Fertility and Sterility  , DOI: ( /j.fertnstert )
Copyright © 2015 American Society for Reproductive Medicine Terms and Conditions