Background and Aim: Hematocrit is defined as the relationship between the volume of cells and the volume of blood separated by a centrifuge. Evaluation of hematocrit is one of the routine tests during pregnancy. Researches have shown that there is a significant relationship between both high and low levels of hematocrit and adverse outcomes of pregnancy. This study aimed at examining the relationship between first and third trimester hematocrit, and birth weight and preeclampsia.

  Materials and Methods: A descriptive and analytic research was performed on 322 pregnant women who referred to health centers in Esfahan during research period. Data were collected by questionnaire through interview with subjects and medical records. Data were analyzed with T-test and one-way ANOVA.

  Results: A statistically significant relationship between first and third trimester hematocrit and preeclampsia was found (P<0.001 and P<0.04, respectively), but, there was not a statistically significant association between first and third trimester hematocrit and birth weight (P>0.05).

  Conclusion: It seems that there is a U-shaped relationship between hematocrit level and preeclampsia, so, further study is suggested