Anaemic parturient and the anaesthesiologist: Are we asleep at the wheel?
Blood loss during uneventful childbirth varies with the type of delivery and ranges normally between 200 and 400 ml. However, significant blood loss resulting in PPH can occur rapidly. PPH is defined in Australia as blood loss of 750 ml or more after caesarean delivery or 500 ml or more after vaginal birth. Risk factors for PPH are increasing worldwide and include advanced maternal age and obesity, as well as caesarean section; with rates exceeding 30%, this is the most commonly performed major surgical procedure in the United States.4 Worldwide PPH rates show geographical variation and are on average estimated to affect 11% of all women, with 4.2% suffering severe PPH.5
In well defined scenarios, such as bleeding disorders, grand multiparity and abnormal placentation, a higher risk of bleeding is generally flagged and management often carefully planned. However, it is imperative to be vigilant and keep in mind that every woman can bleed during childbirth. Identification of factors that can minimise the impact of potential blood loss and/or reduce the rate of PPH should be considered in the antenatal period. One such factor is anaemia.
Anaemia is a demonstrated risk in any perioperative setting, including obstetrics. Anaemia increases the risk of morbidity, mortality and blood transfusion. In the presence of anaemia, any nonemergency surgical procedure potentially associated with blood loss should be delayed to allow enough time to optimise the patient's own red blood cell mass and improve outcome.6,7
Pillar one of patient blood management (PBM) includes steps to assure timely identification and management of conditions such as iron deficiency and anaemia, which have been shown to be effective for transfusion reduction, enhanced patient safety, faster recovery, shorter hospital stays and economic benefits7,8 Defined risk groups, such as patients requiring colorectal, orthopaedic or cardiac surgery, are already benefitting from the attention and appropriate treatment modalities brought to them by PBM.8–10 Anaesthesiologists are often involved in the preoperative management and optimisation of patients scheduled for elective major surgery. However, the implementation of PBM strategies remains extremely variable, particularly in the preoperative setting.11,12 Obstetric patients may benefit from the introduction of clear PBM strategies, particularly those patients with iron deficiency and/or anaemia.
Although morbidity and mortality from severe PPH is high, women entering labour in an anaemic state and/or with iron deficiency are exposed to an even higher risk.13 Iron repletion and haemoglobin (Hb) optimisation prior to delivery are of pivotal importance, can easily be achieved and offer an important and protective strategy to reduce the need for peri-partum transfusion.14 Antenatal screening for iron deficiency, reflecting pillar one of the PBM concept, should be routine for women at risk of anaemia or iron depletion.15 If detected, iron deficiency should be treated early to benefit the mother and the unborn.13 Oral iron remains the first-line treatment, but adequate response needs to be assured. In the non-responsive, non-tolerant or non-compliant pregnant woman, or if iron deficiency anaemia is detected late in pregnancy, intravenous iron offers a well tolerated and effective approach.16
Improving Hb, even at a late stage of the third trimester, may shield some mothers from the risks of an allogeneic transfusion.16,17 This not only spares resources, but also optimises the health of women throughout and beyond their pregnancy into the challenging post-partum period.