Pregnancy: Importance of Iron in Prenatal Development
Despite many modern advances in health, iron deficiency still remains as one of the primary nutritional disorders in the world, placing it second only to tuberculosis as the world most common and costly health problem. Iron deficiency is a condition that affects individuals not only in developing nations but also in developed nations.
In industrialised nations, iron deficiency is most prevalent in children, women of childbearing age and in pregnant women. WHO estimates that about 56% of pregnant women are anaemic. Even women who enter pregnancy with sufficient iron stores are at risk of developing iron deficiency. This is because pregnancy is a period of rapid growth for both mother and foetus making them vulnerable to the changes in dietary supply of micronutrients, such as iron.
Numerous studies have indicated that iron deficiency during pregnancy places both mother and baby at risk of pregnancy complications, increased mortality and future health problems. Mothers with iron deficiency anaemia have a higher risk of morbidity and mortality. They experience reduced fertility, foetal viability, and they also have an increased risk of giving birth to premature and/or smaller babies. Iron deficiency during pregnancy not only increases the complications during pregnancy but has short- and long-term effects on the baby after birth.
The effects of iron deficiency depend on the severity of the deficiency with a mild deficiency having little effect. However, the importance of iron in foetal development cannot be sufficiently stressed as the problems related to iron deficiency escalate as the severity of the deficiency increases. Iron deficiency during pregnancy has the following effects on the developing foetus. It increases the baby's risk of:
- Being born premature.
- Being born with reduced foetal weight.
- Asymmetrical organ growth - infants have been born with reduced foetal liver weights, and disproportionate foetal growth. Studies in rats found that infant rats were born with larger hearts and smaller kidneys.
- Developing iron deficiency after delivery - infants of mothers with iron deficiency display more pronounced anaemia at 10-12 weeks postnatal.
It also reduces the baby's survival rate. Studies in rats have shown that postnatal survival rates were reduced by as much as 25%.
The effects of iron deficiency are felt not only during pregnancy and immediately after delivery. They can affect the future health and development of the infant. Infants of mothers with iron deficiency during pregnancy are at risk of:
- Increased blood pressure
- Increased glucose tolerance
- Impaired cognitive and behavioural impairment - poor foetal iron status is related to reduced language ability, fine motor skills and tractability as determined at 5 years of age. Studies have found that maternal iron deficiency causes persistent alterations in cognitive and behavioural function which are not reversible even with postnatal iron supplement.
Iron deficiency during pregnancy has also been shown to correlate with an increased placental weight to birth weight ratio. This ratio has been found to be indicative of an infant's vulnerability to developing diseases such as cardiovascular problems and diabetes in later life.
It is evident that iron deficiency during pregnancy can have serious consequences for the baby during pregnancy, after birth and in later life. Although much of the information has been obtained from animal studies, the milder effects of maternal iron deficiency on infant cognitive ability suggest that humans have the same vulnerability to iron deficiency. To limit potential health problems developing, it is important that all mothers be aware of the effects of iron deficiency when they are pregnant and that they take steps to prevent it.