Association between different levels of hemoglobin in pregnancy and pregnancy outcomes: a registry-based study in Northwest Russia

Abstract

The association between maternal anemia andpregnancy outcomes has been investigated inmany epidemiological studies, but the findingsremain inconsistent. In our previousstudy based on the Kola Birth Registry (KBR), we observed that maternal anemia defined ashemoglobin concentration below 120 g/l wasnegatively associated with the risk of stillbirthand preterm birth and positively associatedwith foetal growth (1). However, our anemicgroup was heterogeneous and included womenwith hemoglobin between 110 and 120 g/l, which cannot be classified as anemic accordingto the WHO. This study aims to achieve a moredetailed analysis of different maternal hemoglobinconcentrations and their associationswith stillbirth, preterm birth and foetal growthin using the data from the KBR.