MATERNAL ANEMIA DURING PREGNANCY IS AN INDEPENDENT RISK FACTOR FOR LOW BIRTHWEIGHT AND PRETERM DELIVERY

Eur J Obstet Gynecol Reprod Biol,October 1, 2005; 122(2): 182-6.

The present study was designed to investigate the outcome of pregnancy and delivery in patients with anemia.

A retrospective population-based study comparing all singleton pregnancies of patients with and without anemia was performed. Deliveries occurred during the years 1988-2002 in the Soroka University Medical Center. Maternal anemia was defined as hemoglobin concentration lower than 10 g/dl during pregnancy. Patients with hemoglobinopathies such as thalassemia were excluded from the analysis. Multiple logistic regression models were performed to control for confounders.

During the study period there were 153,396 deliveries, of which 13,204 (8.6%) occurred in patients with anemia. In a multivariable analysis, the following conditions were significantly associated with maternal anemia: placental abruption, placenta previa, labor induction, previous cesarean section (CS), non-vertex presentation and Bedouin ethnicity. Higher rates of preterm deliveries (<37 weeks gestation) and low birthweight (<2500 g) were found among patients with anemia as compared to the non-anemic women (10.7% versus 9.0%, p < 0.001 and 10.5% versus 9.4%, p < 0.001; respectively). Higher rates of CS were found among anemic women (20.4% versus 10.3%; p < 0.001). The significant association between anemia and low birthweight persisted after adjusting for gender, ethnicity and gestational age, using a multivariable analysis (OR = 1.1; 95% CI 1.0-1.2, p = 0.02). Two multivariable logistic regression models, with preterm delivery (<37 weeks gestation) and low birthweight (<2500 g) as the outcome variables, were constructed in order to control for possible confounders such as ethnicity, maternal age, placental problems, mode of delivery and non-vertex presentation. Maternal anemia was an independent risk factor for both, preterm delivery (OR = 1.2; 95% CI 1.1-1.2, p < 0.001) and low birthweight (OR = 1.1; 95% CI 1.1-1.2, p = 0.001).

Maternal anemia influences birthweight and preterm delivery, but in our population, is not associated with adverse perinatal outcome.