control such as physical activity and diet control.

To examine the influence of the maternal pre-pregnancy hemoglobin concentration on the perinatal outcome.Population based retrospective cohort study was conducted on 41,975 mothers who received health examination in 1997, and delivered a singleton live baby in 1999 or a singleton stillbirth in 1999. Rate and odds ratio of stillbirth, preterm birth, and low birthweight in accord with the level of pre-pregnancy hemoglobin level was examined. Results were adjusted for maternal age at delivery and pre-pregnancy body mass index using logistic regression model.