Even a small PPH may become life-threatening if the mother is anaemic. Anaemia predisposes to infection, and makes heart failure worse. Worn-out, anaemic mothers may not cope with their offspring. Anaemia is the main cause of perinatal problems associated with malaria; above all, anaemia is a leading mechanism by which poverty exacts its morbid toll in pregnancy.
WHO definition of anaemia of pregnancy
Hb <11g/dL. By this standard 50% of women not on haematinics become anaemic. The fall in Hb is steepest around 20 weeks' gestation, and is physiological (p 6); indeed failure of Hb to fall below 10.5g/dL (but not further than ~9.5g/dL) indicates รข†‘risk of low birth weight or premature delivery.
Who is prone to anaemia?
Those who start pregnancy anaemic, eg from menorrhagia, hookworm, malaria, with haemoglobinopathies; those with frequent pregnancies, twin pregnancy, or a poor diet.
Antenatal screening
includes Hb estimation at booking, at 28 and 36 weeks. In black patients do sickle-cell tests, in others of foreign descent consider Hb electrophoresis for other haemoglobinopathies. From malarious areas consider malaria, and thick films. See p 27.
Treatment
Pregnancy increases iron needs by 700 1400mg (per pregnancy), provided for by a pregnancy-induced 9-fold increase in iron absorption. Iron and folate supplements (and prevention against hookworm and malaria) are recommended in many developing countries.13
Offer iron to those likely to be iron deficient (see above) or who would refuse transfusion if haemorrhaging (p 85). Parenteral iron may be given (to those with iron deficiency anaemia not tolerating oral iron) as iron dextran or iron sucrose. Beware anaphylaxis. Use only if cardiopulmonary rescuscitation facilities to hand. Hb rises over 6 weeks, so late severe anaemia (Hb <9g/dL) may need blood transfusion. One unit of blood increases the Hb by ~0.7g/dL.
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