Midwifery Practice: Pre-Existing Pathphysiology and Pharmacology Principles

Iron Deficiency Anaemia in Pregnancy

Anaemia is a condition caused by a reduction in the number of red blood cells or the haemoglobin concentration of blood, resulting in an insufficiency in the body (WHO 2014). Types of anaemia can vary, although the most common type is recognised as iron deficiency anaemia or IDA. Other forms of anaemia include; folate deficiency anaemia, vitamin B12 deficiency anaemia and inherited haemoglobinopathies i.e. sickle cell disorders and thalassaemia (Rankin 2017).

IDA occurs as a result of an inadequate supply of iron. The progressive diminishment of iron stores, in the form of hemosiderin and ferritin, result in a negative iron balance which effects the body’s ability to transport oxygen (Uthman 2009). This type of anaemia is mainly prompted by;

an insufficient intake or absorption of iron,

the increased demand for iron during pregnancy, especially in cases of frequent and multiple pregnancies as ferritin stores have not yet been restored

and blood loss/ iron loss e.g. in menstruation and postpartum haemorrhages.

Based on WHO (2014, 2016) documents, it is estimated that anaemia effects about 40% of pregnancies worldwide, 50% of which are due to iron deficiency. IDA is a pathology more common in pregnancy due to the increased demands for iron in pregnancy. This high incidence is of concern, as IDA in pregnancy can be linked to premature labour, PPH and/or a low neonatal birth weight (Allen 2000), which could have serious implications.

PREVENTION

In view that the prevalence of anaemia is so plentiful in women, caution and appropriate planning is a necessity before entering pregnancy, making sure to tackle factors that may have adverse effects on maternal and neonatal health (Soltani & Fair 2017a). Pre conceptual care can be used as a preventative tool to help rid iron deficiency in pregnancy. Pre conceptual care improves prospective parents’ and their child’s health (short and long term) by creating the optimum environment for conception and early foetal development. Women with high risk factors, e.g. poor dietary habits, should be priority for midwives (Macdonald & Johnson 2017).

The woman should be advised to seek out blood tests in order to check her iron and ferritin levels prior to conception (Dhavliker & Purohit 2017). Screening for anaemia and knowledge of low iron levels preconceptually, will allow time for the woman to build her iron stores.

Timing of the woman’s first visit is key. Anaemia in pregnancy can easily be treated if it is intercepted early on. Because of this, the need for the woman to attend her antenatal appointment should be reinforced. WHO (2016) recommends that women should have their first antenatal visit in the first 12 weeks of pregnancy.

Highlighting risk factors during the woman’s detailed history at the booking visit is important. The woman should be informed who is most at risk of becoming anaemic, in addition to what can put a healthy woman at risk.

Having a healthy balanced diet before, during and after pregnancy, should also be of large focus for the woman. Initial advice given to the woman, by the midwife, should be to alter her diet to incorporate iron rich food, if she has not already begun the process. This is due to the simple reasoning that, anaemia can easily be prevented or reduced by eating iron-rich foods. The woman should focus on eating fresh leafy green vegetables, red meats and poultry, along with whole grain breads and rolls. Furthermore, an increased amount of Vitamin C, i.e. kiwis, oranges, broccoli, should be consumed in order to aid the absorption of iron. Inhibitors such as polyphenols, i.e. teas and coffees, should be avoided (Macdonald & Johnson 2017, NHS 2018).

DETECTION

Per NICE (2008) guidelines, all pregnant women should be provided screening for iron deficiency anaemia (as well as other anaemias) in early pregnancy. This should take place during the woman’s booking appointment and again at 28 weeks. These time frames enable appropriate time for treatment and management of IDA, if detected. While physiological anaemia is a normal occurrence in pregnancy, caused by an increase in plasma volume which provokes haemodilution, pathological anaemia occurs in cases of deficiency, haemorrhage and inheritance (Chowdhury et al. 2014). The midwife should be vigilant in detecting early signs of iron deficiency and distinguishing between these two. Evaluating the woman’s physical appearance for common signs of paleness, pallor of mucous membranes and fatigue can be useful, but it may also be misleading for women with naturally pale skin, darker skin or a naturally tired appearance. Using signs in conjunction with symptoms will help properly assess the woman. Symptoms to look for can include irritability, tiredness, weakness, breathlessness, tachycardia, and chest pains (Rankin 2017, Colman & Pavord 2017). The midwife should take a thorough history including questions regarding; nutritional habits (reduction in consumption amounts), any previous excessive menstrual bleeding/ heavy menses, gastrointestinal upset in prior pregnancies, short gaps between each pregnancy or multiple pregnancies and any previous antepartum or postpartum haemorrhages. The WHO (2011) states that, haemoglobin levels under 11g/dl for pregnant women is categorised as a form of anaemia ranging from mild to moderate to severe. While NICE (2008) defines the normal haemoglobin range for a pregnant woman as, 11 g/dl at first appointment and 10.5 g/dl at the follow on 28-week appointment. Although ranges are given, it is also necessary to be aware that ranges may differ in accordance with different ethnic backgrounds i.e. in various studies African women have shown to have a lower normal haemoglobin baseline in comparison to white women (Johnson-Spear & Yip 1994, Perry et al. 1992). Any signs of severe anaemia should be referred to the multi-disciplinary team.

MANAGEMENT

Information regarding dietary consumption of iron should be given to the woman. This should highlight how to improve intake and increase absorption. The midwife should consider how dietary habits may be affected by cultural or religious factors.

A full blood count is recommended as a method for checking haemoglobin concentration and screening for anaemia in pregnancy (WHO 2016). Serum ferritin measurement is also an excellent test for IDA. This is because iron deficiency is a microcytic anaemia, which causes a reduction in the mean cell volume and serum ferritin. Checking for this reduction is ideal as it is an earlier sign and occurs before the reduction in Hb (Rankin 2017).

After investigation, only if indicated, iron supplementation should be considered (NICE 2008). The route of administration depends on the severity of anaemia, gestational age and tolerability of iron. The first preferred route for iron supplementation is orally (Rankin 2017) as it is the most effective way to replace the iron needed to increase haemoglobin levels. This can have various preparations, examples being ferrous gluconate, sulphate or carbonate, and carbonyl iron. The NHS (2018) recommends ferrous sulphate tablets for treating IDA, but Gordeuk et al. (1986) voiced that, in comparison, carbonyl iron is more tolerable to the stomach than ferrous iron as it enters the system gradually. The recommended daily intake of iron for pregnant women, in settings where anaemia is prevalent (

≥

40%), is 60mg for six months while pregnant and three months post pregnancy (Stoltzfus & Dreyfuss 1998, WHO 2016). If Hb levels fall two standard deviations below the mean for a healthy matched person, a therapeutic dose should be started. This increases the daily dose of iron to 120mg of elemental iron per day until the Hb rises to normal. After a normal baseline is achieved, the standard daily dose is resumed to prevent recurrence of anaemia (WHO 2016) There is often poor compliance associated with the intake of oral iron supplementation. This can often be due to effects it has on the woman’s bowels i.e. bloating and constipation (Soltani & Fair 2017b) (Macdonald & Johnson 2017). Women need to be convinced of the significance of iron for their health and wellbeing and of their unborn child’s (DeMaeyer et al. 1989).

Parenteral iron is indicated for women who cannot tolerate or absorb oral iron. An intravenous infusion of iron is preferred over an intramuscular injection due to the effects of intramuscular injections. This injection can be painful, cause bleeding into the muscle, and even cause muscle neoplasms (Cirino 2017). The midwife should consider intravenous iron for women who have insufficient time to intake the necessary quantities of oral iron, i.e. women with iron deficiency anaemia (Hb under 10.4) in their third trimester. IV iron increases haemoglobin levels faster and higher than oral iron (Cançad & Muñoz 2011). Intravenous iron sucrose (Venofer) is given as a divided dose. A maximum of 200mg is given per day, not more than three times per week (twice weekly for pregnant women) (Hinchingbrooke Health Care NHS Trust 2008). According to Kriplani et al. (2013) and the eMC (2016) dosages can be calculated as followed;

“Pre-pregnancy weight[kg] x (target Hb-actual Hb)[g/dl] x 2.4*+ storage iron[mg]”.

Fall in blood pressure is a common adverse drug reaction of IV iron, and in rarer cases of iron toxicity, anaphylactic shock can occur (Cirino 2017). Hb levels should increase by 1g/week.

Blood transfusion is applicable in severe cases of anaemia. This generally occurs after 36 weeks gestation. This anaemia is due to acute blood loss during APH and/or PPH, or after infection. This procedure is undergone as a last course of action if oral or parenteral therapies are not responded to (RCOG 2015)

The key role of the midwife is to promote normality where possible. Soltani & Fair (2017b) states that no extra iron is needed in healthy women with a balanced diet. Because of this routine iron should not take place as there is no advantage to this and can be harmful. Uncontrolled iron consumption can possibly lead to a rise in haemoglobin level and blood viscosity or placental blood transfusion. This can have an adverse effect on birth outcome like premature birth, low neonatal birth weight, intra-uterine growth retardation, SIDS, and foetal abnormalities. Maternal preeclampsia can also result (Alizadeh & Salehi 2016).

References

• Alizadeh, L. & Salehi, L. (2016) Is Routine Iron Supplementation Necessary in Pregnant Women With High Hemoglobin? Iranian Red Crescent Medical Journal, 18(1), 1-5.
• Allen, L. H. (2000) Anemia and iron deficiency: effects on pregnancy outcome. The American Journal of Clinical Nutrition, 71(5), 1280S-1284S.
• Cançad, R. D. & Muñoz, M. (2011) Intravenous iron therapy: how far have we come? Revista Brasileira de Hematologia e Hemoterapia, 33(6), 461-469.
• Chowdhury, S., Rahman, M. & Moniruddin, A. B. M. (2014) Anaemia in Pregnancy. Medicine Today, 26(1), 49-52.
• Cirino, E. (2017) What to Expect from an Iron Infusion. Retrieved from https://www.healthline.com/health/iron-infusion on 28 March 2019.
• Colman, K. & Pavord, S. (2017) Iron Deficiency Anaemia in Pregnancy. Oxford University Hospital NHS Trust Foundation, Oxford.
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• Macdonald, S. & Johnson, G. (2017) Mayes’ Midwifery, 15^th edn. Elsevier Limited, London
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• Soltani, H. & Fair, F. (2017) Nutrition and metabolism during pregnancy. In Physiology in Childbearing with Anatomy and Related Biosciences, 4^th edn. (J. Rankin, eds.) Elsevier Limited, pp. 239-248.
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• Stoltzfus, R. J. & Dreyfuss, M. L. (1998) Guidelines for the Use of Iron Supplements to Prevent and Treat Iron Deficiency Anemia. ILSI Press, Washington.
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• World Health Organisation (2014) Global Nutrition Targets 2025: Anaemia policy brief. Retrieved from https://www.who.int/nutrition/publications/globaltargets2025_policybrief_anaemia/en/ on 24 March 2019.
• World Health Organisation (2016) WHO recommendations on antenatal care for a positive pregnancy experience. World Health Organisation, Geneva.