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ANAEMIA IN PREGNANCY: A PRACTICE UPDATE FOR MIDWIVES IN AOTEAROA ESTHER CALJÉ REGISTERED MIDWIFE, PHD CANDIDATE
Iron-deficiency and anaemia are common problems in pregnancy and postpartum, however, even in well-resourced countries, the management of maternal anaemia and iron status is recognised as inconsistent and suboptimal. This may be due to clinical guidance that was, until recently, very limited. Many district health boards (DHB) in Aotearoa New Zealand have responded with the development of guidelines, such as Canterbury DHB’s Maternal Blood Optimisation Pathways (MBOP), to assist midwives in managing anaemia and irondeficiency in pregnancy. The development of these multi-disciplinary guidelines may be driven by the increased use of intravenous (IV) iron, and the international focus on improving patient blood management (PBM). PBM is relevant to midwives, as pillar one of PBM aims to optimise blood volume and red cell mass in pregnancy to avoid the requirement - and risks - of blood transfusion around the time of birth. Midwives also understand that the management of anaemia and iron-deficiency in pregnancy and postpartum is important for the health and well-being of women, and their pēpi.
20 | AOTEAROA NEW ZEALAND MIDWIFE
WHAT IS ANAEMIA? Anaemia is a lack of haemoglobin (Hb) and red blood cells, which leads to reduced transport and supply of oxygen to the tissues and vital organs. Although physiological anaemia of pregnancy reflects plasma expansion and haemodilution associated with normal pregnancy, the boundary between physiological anaemia and anaemia as a disorder, is unclear. Internationally, definitions of anaemia in pregnancy are inconsistent, which can be confusing for maternity care providers. Ideally, we would define anaemia in pregnancy based on a large population study of healthy iron-replete pregnant women in Aotearoa, which would give us a statistically established definition of anaemia in our population. However, in the absence of such a population study, it is reasonable to adopt anaemia thresholds based on recognised international guidelines with similar populations (see Box 1). ADVERSE EFFECTS OF ANAEMIA Anaemia is the most common indirect cause of adverse maternal outcomes and is
associated with fatigue, lethargy, depression, reduced thermoregulation, impaired breastfeeding, bonding and cognition, and reduced physical performance and work capacity. Clinically, maternal anaemia is associated with increased mortality and morbidity, cardiovascular stress, increased risk of infection, poor wound healing, prolonged hospital stays, increased hospital costs and increased risk of interventions such as blood transfusion and intravenous iron. Furthermore, maternal anaemia is linked to reduced fetal growth and prematurity (especially when the anaemia is from early pregnancy), low neonatal/infant iron stores and infant neurodevelopmental delay. Conversely, high haemoglobin levels in pregnancy (Hb >130g/L) are associated with hypertension, increased blood viscosity, decreased placental perfusion, reduced fetal growth and prematurity. WHO DOES IT AFFECT? Worldwide, it is estimated that anaemia in pregnancy significantly affects about half of all women in low-income countries, and 2530% of women in well-resourced countries.
