Maternal Anemia and Adverse Pregnancy Outcomes
Summary
Maternal anaemia, defined by low haemoglobin concentrations during pregnancy, affects more than a third of pregnancies worldwide and remains a leading contributor to maternal and neonatal morbidity. The condition arises most commonly from iron deficiency but may also reflect inflammation or other micronutrient shortfalls. Its clinical significance spans a spectrum of complications: women with moderate to severe anaemia are at increased risk of preterm birth, low birth weight, small for gestational age infants, pre-eclampsia, and postpartum haemorrhage. Conversely, high haemoglobin concentrations have been linked to impaired placental perfusion and similar perinatal risks, yielding a U-shaped association with adverse outcomes. Globally, this burden is unevenly distributed, with the highest prevalence in low- and middle-income regions where dietary iron intake, parasitic infections and access to antenatal care vary markedly. Effective screening and context-specific interventions, including tailored iron supplementation and nutritional counselling, have demonstrated reductions in the incidence of low birth weight and improvements in maternal iron stores. Ongoing research seeks to refine haemoglobin thresholds for risk stratification and to define optimal timing and dosing of preventive strategies.
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Maternal Anemia and Adverse Pregnancy Outcomes publication trend
The graph below shows the total number of articles in maternal anemia and adverse pregnancy outcomes across all publications each year (not limited to Nature Index journals).
Technical terms
Haemoglobin concentration: the amount of haemoglobin per unit volume of blood, usually expressed in grams per litre (g/L).
Iron deficiency anaemia: anaemia resulting specifically from inadequate iron for haemoglobin synthesis, often defined by low serum ferritin and transferrin saturation.
Preterm birth: delivery of an infant before 37 completed weeks of gestation.
Low birth weight (LBW): birth weight less than 2,500 g at term.
Small for gestational age (SGA): an infant weight below the 10th percentile for its gestational age, indicating intrauterine growth restriction.
Pre-eclampsia: a multisystem pregnancy disorder characterised by new-onset hypertension and organ dysfunction, typically after 20 weeks’ gestation.
References
- Association between maternal haemoglobin concentrations and maternal and neonatal outcomes: the prospective, observational, multinational, INTERBIO-21st fetal study. The Lancet Haematology (2023).
- Maternal hemoglobin levels and adverse pregnancy outcomes: individual patient data analysis from 2 prospective UK pregnancy cohorts. American Journal of Clinical Nutrition (2023).
- Maternal hemoglobin concentrations across pregnancy and child health and development from birth through 6–7 years. Frontiers in Nutrition (2023).
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