Introduction
Iron supplements for pregnancy are a crucial aspect of prenatal care, as the increased demand for iron during this time can lead to deficiency if not adequately met through diet alone. Pregnant women require significantly more iron to support the growth and development of the fetus, placenta, and their own expanded blood volume (Institute of Medicine, 1990). iron deficiency is the most common nutritional deficiency worldwide, affecting a staggering 51% of pregnant women globally (DeMaeyer and Adiels-Tegman, 1985 as cited in Institute of Medicine, 1990).
The consequences of iron deficiency during pregnancy can be severe, ranging from maternal anaemia to increased risk of low birth weight and preterm delivery (Pena-Rosas et al., 2015 as cited in Georgieff et al., 2020). iron is essential for the production of haemoglobin, which carries oxygen to the developing fetus, and for the proper functioning of iron-dependent enzymes involved in cellular energy production (What to Expect, n.d.). Therefore, ensuring adequate iron status through a combination of diet and supplementation is of paramount importance for the health of both mother and child.
This comprehensive article will delve into the intricacies of iron supplements for pregnancy, exploring the increased iron requirements during this critical period, the prevalence and risk factors for deficiency, the benefits of supplementation, and important considerations for dosage, timing, and monitoring. By providing evidence-based information and practical guidance, we aim to empower expectant mothers and healthcare providers to make informed decisions regarding iron supplementation, ultimately promoting optimal maternal and fetal health outcomes.
iron Requirements in pregnancy
Pregnant women have significantly higher iron requirements compared to non-pregnant women due to the increased demands of the growing fetus, placenta, and expanded maternal blood volume. The total body iron requirement for an average pregnancy is approximately 1,000 mg (Hallberg, 1988 as cited in Institute of Medicine, 1990). This can be broken down into 350 mg transferred to the fetus and placenta, 250 mg lost in blood at delivery, 450 mg required for the increased maternal red cell mass, and 240 mg for basal losses (Institute of Medicine, 1990).
To meet these increased demands, pregnant women need to consume 27 mg of iron per day, compared to the 18 mg recommended for adult women (What to Expect, n.d.). Most prenatal vitamins include this amount of iron, but iron-deficiency anaemia remains common in pregnancy due to the challenges of meeting such high requirements through diet alone (What to Expect, n.d.).
Prevalence of iron Deficiency in pregnancy
iron deficiency is a global health concern, with pregnant women being particularly vulnerable. The World Health Organization estimates that 51% of pregnant women worldwide are anaemic, with iron deficiency being the primary cause (DeMaeyer and Adiels-Tegman, 1985 as cited in Institute of Medicine, 1990). In the United States, data from the National Health and Nutrition Examination Survey II (NHANES II) suggests that 5-10% of pregnant women have iron deficiency, although this is likely an underestimate (Institute of Medicine, 1990).
Longitudinal studies conducted in Europe have demonstrated a high prevalence of iron deficiency in pregnant women who do not receive supplementation, particularly by late pregnancy (Institute of Medicine, 1990). These findings highlight the importance of routine screening and supplementation to prevent and treat iron deficiency during this critical period.
Groups at Higher Risk for iron Deficiency
Certain subgroups of pregnant women are at a higher risk of developing iron deficiency. Those with low socioeconomic status, limited education, black or Hispanic ethnicity, and high parity have been shown to have higher rates of iron deficiency (LSRO, 1984 as cited in Institute of Medicine, 1990). Adolescent pregnancies may also be at increased risk due to the competing demands of the mother’s own growth and development (Institute of Medicine, 1990).
Healthcare providers should be aware of these risk factors and provide targeted screening and supplementation strategies to prevent and treat iron deficiency in these vulnerable populations.
Benefits of iron Supplementation
The benefits of iron supplementation during pregnancy have been well-established through numerous randomised controlled trials. In iron-deficient pregnant women, supplementation has been shown to improve haemoglobin and ferritin levels and reduce the prevalence of anaemia compared to placebo (Pena-Rosas et al., 2015 as cited in Georgieff et al., 2020). This is crucial for ensuring adequate oxygen delivery to the developing fetus and supporting optimal growth and development.
iron supplementation in iron-deficient pregnant women has also been associated with a reduced risk of low birthweight and preterm birth (Pena-Rosas et al., 2015 as cited in Georgieff et al., 2020). These findings underscore the importance of maintaining adequate iron status throughout pregnancy to promote the best possible outcomes for both mother and child.
iron Supplementation in Malaria-Endemic Areas
In regions where malaria is prevalent, the provision of iron supplements must be carefully considered. There have been concerns that iron supplementation may increase the risk of malaria infection in pregnant women. However, recent evidence suggests that when iron is provided in conjunction with malaria prevention and treatment services, maternal outcomes can be improved without an increased risk of malaria (Mwangi et al., 2015 as cited in Georgieff et al., 2020).
Healthcare providers in malaria-endemic areas should follow local guidelines and work closely with infectious disease specialists to ensure the safe and effective implementation of iron supplementation programs for pregnant women.
Considerations for Dosage and Timing
Determining the appropriate dosage and timing of iron supplements during pregnancy is essential for optimising maternal and fetal health while minimising potential side effects. Current recommendations suggest that a daily dose of 30 mg of elemental iron, starting from week 12 of gestation, is as effective as higher doses in preventing iron deficiency anaemia (Chanarin and Rothman, 1971 and others as cited in Institute of Medicine, 1990).
If anaemia is already present, a higher dose of 60-120 mg per day, divided into multiple doses, may be necessary until haemoglobin levels return to the normal range. Once this is achieved, a maintenance dose of 30 mg per day can be used (Institute of Medicine, 1990).
Strategies for Improving Absorption and Tolerability
iron is best absorbed on an empty stomach, but this can often lead to gastrointestinal side effects such as nausea and constipation. To improve tolerability, pregnant women can consider using sustained-release iron preparations or taking supplements intermittently, such as every other day (Institute of Medicine, 1990). Consuming iron supplements with vitamin C-rich foods or beverages can also enhance absorption (What to Expect, n.d.).
It is important for pregnant women to discuss their individual needs and concerns with their healthcare provider to determine the most appropriate supplementation strategy.
Screening and Monitoring iron Status
Regular screening and monitoring of iron status during pregnancy is crucial for identifying and treating deficiencies in a timely manner. Haemoglobin concentration alone has limitations as a screening tool, as it can be affected by factors such as haemodilution and does not reflect iron stores (Institute of Medicine, 1990). The use of serum ferritin in conjunction with haemoglobin can improve the detection of iron deficiency in pregnant women (Institute of Medicine, 1990).
Emerging research suggests that hepcidin, an iron-regulatory hormone, may be a useful biomarker for guiding iron supplementation in the future (Georgieff et al., 2020). Hepcidin levels reflect both iron stores and the body’s ability to absorb and utilise iron, providing a more comprehensive assessment of iron status.
Timing and Frequency of Screening
The timing and frequency of iron status screening during pregnancy may vary depending on individual risk factors and local guidelines. Generally, it is recommended that all pregnant women be screened for anaemia at their first prenatal visit and again in the late second or early third trimester (Institute of Medicine, 1990). Women with identified risk factors or those living in areas with a high prevalence of iron deficiency may require more frequent monitoring.
Healthcare providers should stay up-to-date with the latest evidence-based guidelines and adapt their screening and monitoring practices accordingly to ensure the best possible care for their patients.
Conclusion
iron supplementation during pregnancy is a crucial component of prenatal care, ensuring optimal maternal and foetal health outcomes. The increased demand for iron to support the growing foetus, placenta, and expanded maternal blood volume can lead to deficiency if not adequately met through diet alone. iron deficiency anaemia affects a significant proportion of pregnant women worldwide, with potentially severe consequences such as increased risk of low birth weight and preterm delivery.
The benefits of iron supplementation in pregnancy have been well-established, with randomised controlled trials demonstrating improved haemoglobin and ferritin levels, reduced anaemia prevalence, and better birth outcomes in iron-deficient pregnant women. However, the appropriate dosage and timing of supplementation must be carefully considered to maximise benefits while minimising side effects. Current recommendations suggest a daily dose of 30 mg of elemental iron starting from week 12 of gestation, with higher doses of 60-120 mg per day for women with pre-existing anaemia. Strategies such as using sustained-release preparations, intermittent supplementation, and co-administration with vitamin C-rich foods can improve absorption and tolerability.
Regular screening and monitoring of iron status during pregnancy is essential for identifying and treating deficiencies promptly. While haemoglobin concentration alone has limitations as a screening tool, the use of serum ferritin in conjunction with haemoglobin can improve the detection of iron deficiency. Emerging research suggests that hepcidin, an iron-regulatory hormone, may be a useful biomarker for guiding supplementation in the future.
In conclusion, iron supplements for pregnancy play a vital role in promoting optimal maternal and foetal health. Healthcare providers should stay informed about the latest evidence-based guidelines and work closely with their patients to develop individualised supplementation strategies that take into account their unique needs and risk factors. By prioritising iron supplementation as a key aspect of prenatal care, we can work towards ensuring the best possible outcomes for mothers and their babies.
Key Highlights and Actionable Tips
- Daily iron and folic acid supplementation is recommended by WHO as part of antenatal care to reduce the risk of low birth weight, maternal anaemia, and iron deficiency.
- The suggested dose is 30-60 mg of iron (higher dose preferred in settings with severe anaemia prevalence ≥40%) along with 400 μg of folic acid daily throughout pregnancy.
- Intermittent iron and folic acid supplementation (120 mg elemental iron and 2800 μg folic acid weekly) is an alternative for non-anaemic women in areas with anaemia prevalence <20%.
- Improving iron and folic acid intake by women of reproductive age could improve pregnancy outcomes and maternal and infant health.
- Folic acid supplementation before conception and during the first trimester decreases the risk of neural tube defects.
What are the consequences of anaemia during pregnancy?
Anaemia during pregnancy places women at risk for poor pregnancy outcomes, including maternal mortality. It also increases the risks for perinatal mortality, premature birth, and low birth weight. Infants born to anaemic mothers have less than half the normal iron reserves. Morbidity from infectious diseases is increased in iron-deficient populations due to the adverse effect of iron deficiency on the immune system.
How can iron and folic acid supplementation improve maternal and child health?
iron and folic acid supplementation is used to improve the iron and folate status of women before and during pregnancy in communities where food-based strategies are not yet fully implemented or effective. It can reduce the risk of low birth weight, maternal anaemia, and iron deficiency. Folic acid supplementation before conception and during the first trimester also decreases the risk of neural tube defects.
What is the recommended dose of iron and folic acid supplementation for pregnant women?
The World Health Organization recommends a daily dose of 30-60 mg of elemental iron (higher dose preferred in settings with severe anaemia prevalence ≥40%) along with 400 μg of folic acid throughout pregnancy, beginning as early as possible after conception. For non-anaemic women in areas with anaemia prevalence <20%, an alternative is intermittent supplementation with 120 mg elemental iron and 2800 μg folic acid weekly.
What factors can limit the effectiveness of iron and folic acid supplementation programmes?
Despite its proven efficacy and wide inclusion in antenatal care programmes, the use of iron and folic acid supplementation has been limited in some settings. Possible reasons include a lack of compliance, concerns about the safety of the intervention among women with adequate iron intake, and variable availability of the supplements at the community level.
How can tracking antenatal iron supplementation help improve nutrition outcomes?
The percentage of women who consumed any iron-containing supplements during their current or previous pregnancy within the past 2 years provides information about the quality and coverage of perinatal medical services. This indicator is included as a process indicator in the core set of indicators for the Global Nutrition Monitoring Framework. Tracking progress can help identify gaps and inform strategies to improve the reach and effectiveness of supplementation programmes.
References
DeMaeyer, E., & Adiels-Tegman, M. (1985). The prevalence of anaemia in the world. World Health Statistics Quarterly, 38(3), 302-316.
Georgieff, M. K., Krebs, N. F., & Cusick, S. E. (2020). The Benefits and Risks of iron Supplementation in pregnancy and Childhood. Annual Review of Nutrition, 39, 121–146. https://doi.org/10.1146/annurev-nutr-082018-124213
Hallberg, L. (1988). iron balance in pregnancy. In H. Berger (Ed.), Vitamins and minerals in pregnancy and lactation (pp. 115-127). Raven Press.
Institute of Medicine (US) Committee on Nutritional Status During pregnancy and Lactation. (1990). iron Nutrition During pregnancy. In Nutrition During pregnancy: Part I Weight Gain: Part II Nutrient Supplements. National Academies Press (US). https://www.ncbi.nlm.nih.gov/books/NBK235242/
LSRO. (1984). Assessment of the iron nutritional status of the U.S. population based on data collected in the Second National Health and Nutrition Examination Survey, 1976-1980. Bethesda, MD: Federation of American Societies for Experimental Biology.
Mwangi, M. N., Roth, J. M., Smit, M. R., Trijsburg, L., Mwangi, A. M., Demir, A. Y., Wielders, J. P., Mens, P. F., Verweij, J. J., Cox, S. E., Prentice, A. M., Brouwer, I. D., Savelkoul, H. F., Andang’o, P. E., & Verhoef, H. (2015). Effect of Daily Antenatal iron Supplementation on Plasmodium Infection in Kenyan Women: A Randomized Clinical Trial. JAMA, 314(10), 1009–1020. https://doi.org/10.1001/jama.2015.9496
Peña-Rosas, J. P., De-Regil, L. M., Garcia-Casal, M. N., & Dowswell, T. (2015). Daily oral iron supplementation during pregnancy. The Cochrane Database of Systematic Reviews, 2015(7), CD004736. https://doi.org/10.1002/14651858.CD004736.pub5
