The relationship of hemoglobin and hematocrit in the first and second half of pregnancy with pregnancy outcome

Background: Considering the relationship of low and high levels of hemoglobin and hematocrit with some pregnancy complications, we decided to study their relationship with pregnancy outcome. This study also aimed to investigate the changes in hemoglobin and hematocrit values during the second and first half of pregnancy and its relationship with pregnancy outcome. Materials and Methods: In a prospective cohort study, 520 Iranian pregnant women, aged 15 to 45 years that were supported by health centers in Isfahan, Iran, were recruited using quota sampling method. Exclusion criteria comprised of 36 conditions that were related to the maternal and infant outcomes. Hemoglobin and hematocrit were measured in eligible mothers during the 6th-11th weeks and 26th-30th weeks of pregnancy. They were monitored until delivery and the data regarding their pregnancy outcome were collected. Findings: Low levels of hemoglobin during the first half of pregnancy was associated with preeclampsia (p = 0.024). Moreover, low levels of hemoglobin during the second half of pregnancy was associated with the risk of preterm premature rupture of membranes (p = 0.01). In addition, mothers with lower blood dilution, as a physiological process during pregnancy, were more prone to preeclampsia (p = 0.04 ). Conclusions: Hemoglobin levels in the first and second half of pregnancy can predict preeclampsia and premature preterm rupture of membranes. Increased hematocrit levels in the second half of pregnancy or lack of reduction of hematocrit levels in the second half compared to the first half can estimate preeclampsia.