Clinical Transfusion

Hormones induce haemodynamic changes. Even though there is an increase in red cell mass, plasma volume increases relatively more [11]. Therefore, obstetric anaemia is defined by specific haemoglobin limits, which are lower than in non-pregnant women. The increased red cell production increases iron needs, which frequently leads to iron depletion, as women in the fertile age often have marginal iron stores [2].

WHO definition: Haemoglobin < 11 g/dL in first and last trimester, and < 10.5 g/dL in the second trimester [5]. BCSH guidelines: Haemoglobin < 11g/dL in first trimester, < 10.5 g/dL in second and third trimesters [12]

May not harm mother or child, but a haemoglobin level below 9 g/dL is associated with a 2-3 fold increased risk for intrauterine growth restriction, which in severe cases may lead to intrauterine foetal death [2].

is by far the most frequent type [9, 9, 13], and is seen in approximately 25% of pregnant women, even in highly industrialized countries, and ethnicity and age are strongly associated with anaemia prevalence [14, 15]. Prevalence of anaemia during pregnancy shows a large geographical variation caused by environmental, socio-economic and hereditary factors: Europe and North America 17-31%, South-East Asia 44-53% and Africa 53-61%. Approximately 20% of who have haemoglobin levels below 8/dL, and Iron deficiency is the most common cause, as the vast majority of women have iron stores too low to meet the cumulative needs of pregnancy and delivery [5, 5, 16].

Folate deficiency, vitamin B12 deficiency, parasitic infestation (malaria, hookworm), bacterial infection, autoimmune haemolytic anaemia, toxic/aplastic anaemias, haematological malignancies and PNH [2, 9].

should be adapted to the geographic region due to the different treatment and prognosis. Clinical and laboratory investigation should at least look for iron and folate deficiency and rule out infection, malignancies and hereditary disorders [2, 17].

IDA can be prevented by taking 15-60 mg of iron diet daily [18] (or 2-3 times per week, which reduces the side effects [19]), though not all countries recommend this [17].

Treatment should target the underlying disease or condition.

Carries a number of risks including volume overload and should only be used for acute bleeding, haematological conditions and severe cases of refractory anaemia, where low haemoglobin levels or insufficient physiological compensation are thought to cause an imminent risk for mother or foetus [17].

Haemoglobin < 10 d/dL [17]

If postpartum anaemia is defined as a Hb < 10 g/dL, the prevalence 30% or higher [17], if defined as < 11g/dL, the prevalence is up to 50%, with no iron intake during pregnancy. With routine intake of iron during pregnancy, postpartum anaemia has been recorded in 14% [21].

Postpartum haemorrhage alone or in combination with pregnancy iron deficiency is a common cause of postpartum anaemia. Other aetiologies: see pregnancy anaemia above.

can be defined > 500 ml of blood loss within 24 hours after delivery [22]. PPH is seen in approximately 18% of all deliveries. Severe PPH, defined as blood loss of > 1000 ml, is seen in 4-5% of deliveries, and PPH > 2500 ml is seen in 0.4% of births [23, 24]. Normally 500 mg of iron is stored in the liver, corresponding to formation of the erythrocytes in 1 litre of blood. If the haemorrhage is severe or there is a pre-existing pregnancy ID or IDA, the blood loss at delivery will almost invariably lead to postpartum IDA.

Treating anaemia during pregnancy and managing obstetric haemorrhage reduces the risk of postpartum IDA, see pregnancy anaemia above, and guidelines for the management of obstetric haemorrhage [25].