Background: The aim of the study was to investigate associations between maternal characteristics, with emphasis on hematological status, and risk of low birth weight and preterm delivery among pregnant women

Methods: In a cohort study, 1,500 pregnant women attending Hazrat Zaynab Hospital for prenatal care and delivery in the period 2000-2001, without any risk factors for preterm delivery and low birth weight were included. Maternal characteristics including hematocrit values were recorded at the first antenatal visit. Main outcome measures included birth weight and gestation at delivery. Linear and logistic regression models were used to analyze data.

Results: Severe anemia (hematocrit< 24%) was associated with a significantly increased risk of low birth weight (<2500 g) and preterm delivery (< 37 weeks gestation). High hematocrit values (> 40%) did not increase the risk of low birth weight and preterm delivery. Teenagers, women with short height or low body mass index had significantly higher risk of delivering low birth weight infants.

Conclusion.: Severe maternal anemia, particularly in the first trimester, was significantly associated with adverse pregnancy outcome. Low maternal age, height or body mass index also increased the risk of low birth weight. Improved nutritional status of young women could contribute to improved health among their infant.