Risk Factors and Consequences of Maternal Anaemia and Elevated Haemoglobin Levels during Pregnancy: a Population-Based Prospective Cohort Study

Background To determine sociodemographic and life style‐related risk factors and trimester specific maternal, placental, and fetal consequences of maternal anaemia and elevated haemoglobin levels in pregnancy. Methods In a population‐based prospective cohort study of 7317 mothers, we measured haemoglobin levels in early pregnancy [gestational age median 14.4 weeks (inter‐quartile‐range 12.5–17.5)]. Anaemia (haemoglobin ≤11 g/dl) and elevated haemoglobin levels (haemoglobin ≥13.2 g/dl) were defined according to the WHO criteria. Maternal blood pressure, placental function and fetal growth were measured in each trimester. Data on gestational hypertensive disorders and birth outcomes was collected from hospitals. Results Older maternal age, higher body mass index, primiparity and European descent were associated with higher haemoglobin levels (P