Iron and vitamin B9 (folate) are essential for the health of both mother and child. The physiological development of the baby and the mother’s immune system are just two examples of their areas of influence. Since deficiencies are connected to maternal anaemia, puerperal sepsis, low birth weight, and risk of preterm birth, the World Health Organization (WHO) recommends additional supplementation along with the consumption of foods rich in iron and vitamin B9.
Calcium is indispensable for the healthy development of the skeletal system (especially the bones and teeth), as well as for muscle function and blood clotting. Deficiencies in calcium during pregnancy are associated with pre-eclampsia. Pregnant women should therefore adapt their diet accordingly and take supplements if calcium intake via food is not sufficient.
Vitamin A exists in different forms, such as retinol or retinyl esters, and can be absorbed from food of animal as well as plant origin. Among others, it affects vision, the immune system, and cell specialisation, with deficiencies possibly leading to anaemia and night blindness. Sufficient vitamin A intake can largely be achieved via consuming specific foods, making supplementation necessary only in context-specific cases.
Iron is an essential micronutrient that plays an important role in many cellular and physiological processes associated with growth and development. Also, iron exists in red blood cells or haemoglobin, and is crucial for the uptake and delivery of oxygen from the blood stream to the lungs (Abbaspour et al, 2014). Anaemia, characterised by inadequate red blood cells and/or haemoglobin in the blood, is a medical condition associated with an iron deficit and is estimated to affect 38.2% of pregnant women globally (WHO, 2016). In addition to anaemia, iron deficiency adversely affects the use of energy sources by the muscle and also influences the immune system (WHO, 2001).
Vitamin B9, also named folic acid or folate, is a water-soluble vitamin essential to several body mechanisms. Vitamin B9 has proven effects on maternal tissue growth during pregnancy, blood formation, immune system function and tiredness and fatigue (EFSA, 2010). Vitamin B9 deficiency is also associated with anaemia complications, and is linked to foetal neural tube defects (WHO, 2012).
The consumption of selected foods helps increase the body's supplies of these nutrients. Foods such as lean red meat, dark-green leafy vegetables, as well as bread and fortified cereals are good sources of iron. Vitamin B9 can be found in foods such as fortified cereals, granary bread, peanuts, fruits (e.g. oranges or raspberries) or vegetables (e.g. asparagus, broccoli and spring greens) (FSA, 2002).
WHO recommends taking daily supplements of elemental iron (30-60mg) and vitamin B9 (400µg) during pregnancy as part of antenatal care. This helps prevent maternal anaemia, puerperal sepsis, low birth weight, and preterm birth (WHO, 2016). It should be noted that excessive iron and folic acid intake can have a negative impact on maternal health. Systemic iron overload is unlikely with normal intestinal function. However, acute large intakes of iron could have a corrosive effect on intestinal mucosa, leading to bleeding and loose stools or even damage to systemic organs, resulting in gastritis, nausea and/or abdominal pain (EFSA, 2015b). During pregnancy specifically, excessive oral iron intake could lead to increased oxidative stress in the body and the small intestines, gastrointestinal side-effects, and accelerated body iron overload in women with genetic haemochromatosis (Milman, 2012). Although vitamin B9 has been shown to provide many benefits during pregnancy, there are also potential health risks with high dosages of this vitamin. High levels of vitamin B9 are able to mask vitamin B12 (cobalamin) deficiency, which is associated with pernicious anaemia. This is a type of anaemia that presents with symptoms such as fatigue, shortness of breath and even neurological effects (including sensory impairment, balance problems and neuropathic pain) (Greenberg et al, 2011). Therefore, it is important that recommendations are followed when taking iron and vitamin B9 supplements in order to support a positive and healthy pregnancy.back
Calcium is a mineral found in many foods and is also an integral component of the skeletal system (especially the bones and teeth). It plays a structural role in the body – needed for tissue rigidity, strength, and elasticity – as well as influencing other physiological processes such as muscle function, blood clotting, and digestive enzyme function (EFSA, 2015a). During pregnancy, calcium deficiency is associated with an increased risk of pre-eclampsia – a medical condition where convulsions occur during late pregnancy due to increased blood pressure (WHO, 2013).
Milk and dairy products are good dietary sources of calcium, presenting high calcium content combined with good bioavailability (i.e. easy absorption). Other sources include leafy green vegetables, soybeans, bread, nuts and dried fruits (FSA, 2002). WHO recommends supplementation in context-specific situations. In populations with low dietary calcium intake, calcium supplementation (1.5-2.0g of oral elemental calcium per day ) is recommended for pregnant women to reduce the risk of pre-eclampsia (WHO, 2016). Excessive calcium is usually associated with the overconsumption of calcium-containing supplements, as opposed to dietary intake alone, and can lead to hypercalcaemia (serum calcium levels around 10.5mg/dL or higher) and/or hypercalciuria (urinary excretion of calcium exceeding 250mg per day). These conditions can cause renal insufficiency, vascular and soft tissue calcification and nephrolithiasis. Also, as a result of the natural hypercalciuria that occurs during pregnancy, pregnant women are at risk of developing kidney stones (Hacker et al, 2012).back
Vitamin A is a fat-soluble vitamin obtained from diet either as preformed vitamin A in foods of animal origin or as provitamin A carotenoids in plant-derived foods. The term vitamin A comprises retinol and the family of naturally occurring molecules with the biological activity of retinol, such as retinal, retinoic acid, and retinyl esters (EFSA, 2015c). Vitamin A is involved in the visual cycle in the retina, systemic maintenance of growth and integrity of cells in body tissue, as well as roles in iron metabolism, the immune system and cell specialisation (EFSA, 2015c). During pregnancy specifically, vitamin A reduces the risk and symptoms of anaemia, infection and night blindness, and reduces the decline in retinol serum levels in late pregnancy. Additionally, given the ability to maintain foetal levels of serum retinol and modest incremental requirements for this vitamin, the benefits to the newborn are restricted to mothers with severe vitamin A deficiency (McCauley et al, 2015). Still, vitamin A deficiencies have been linked to pregnancy-associated concerns such as the risk of anaemia and night blindness (WHO, 2009). In general, vitamin A deficiency affects about 19 million pregnant women worldwide (WHO, 2016).
Dietary sources of vitamin A include dairy products, eggs, carrots, and leafy vegetables (FSA, 2002). WHO recommends supplementation as a context-specific measure in areas where vitamin A deficiency is a severe public health problem for pregnant women. In this way, night blindness can be prevented (WHO, 2016).back