Anemia--prevalence and risk factors in pregnancy

To assess the prevalence of decreased iron stores and anemia in pregnant women. To determine whether the risk factors: socio-demographic background, age, BMI, and parity are associated with abnormal hemoglobin concentrations and/or abnormal iron status.

A longitudinal study was carried out at the Department of Obstetrics, University Hospital of Zurich to establish the risk factors and prevalence of the decreased iron stores and anemia in early pregnancy. In order to determine the hematological parameters and ferritin levels, venous blood samples of 470 singleton pregnancies between 16 and 20 pregnancy weeks were collected. According to hemoglobin and iron status, the patients were divided into four groups: patients with iron deficiency anemia, patients with decreased iron stores, patients with anemia for other reasons and normal patients. The determinants socio-demographic background, age, BMI and parity were explored using multiple logistic regression analysis.

The prevalence of decreased iron stores (ferritin<20 μg/l) was observed in 31.8% of subjects (149/470) and anemia (Hb<110 g/l) in 18.5% (87/470). The prevalence of iron deficiency anemia was higher among women coming from former Yugoslavia and developing countries (p=0.004 and p=0.012). In patients coming from developing countries, a significant increase of anemia for other reasons was observed (p=0.027) and in patients older than 30 years, a significant increase of decreased iron stores (p=0.018).

In our study population with low parity, the prevalence of abnormal hemoglobin and abnormal iron status was 50.2% (236/470), and socio-demographic background was the most important risk factor of anemia.