Depleted maternal iron status early in pregnancy is associated with a higher risk of low birth weight babies

Depleted maternal iron status early in pregnancy is associated with a higher risk of low birth weight babies

June 3, 2015
Weekly Essentials of Health by Usana Health Sciences 
Depleted maternal iron status early in pregnancy is associated with a higher risk of low birth weight babies

At a Glance

A recent study published in British Journal of Nutrition shows that poor iron status early in pregnancy significantly increases the risk of babies born small for gestational age (SGA). 

Read more about this research below. 

Iron deficiency anemia during early pregnancy has long been linked to low birth-weight, preterm birth, and other health problems. But previous research and advice has been based on hemoglobin (Hb) levels (screening for outright deficiencies or anemia), not on other specific measures of iron deficiency.

In a new study published in the British Journal of Nutrition, researchers examined the association between maternal iron status during the first trimester of pregnancy with birth size and preterm birth by using more specific measures of iron deficiency such as serum ferritin, transferrin receptor and their ratio.  

Three-hundred sixty-two infants and their mothers were recruited for this study. Biomarkers and iron measurements were analyzed from maternal blood serum samples that had been taken during the first trimester of pregnancy.

Iron depletion during the first trimester was linked to a higher incidence of SGA. The association was even stronger when Hb measurements were included in the assessment. Although there was no evidence of a link between iron insufficiency and preterm birth, for every 10 g/l increase in the mother’s Hb level during the first half of pregnancy there was a 30% lower risk of SGA. Hb levels below 110 g/l were associated with a 300% increase in SGA risk. Contrary to other research, Hb levels in the second half of pregnancy were not associated with SGA risk.

The results of the present study indicate that depleted iron stores in early pregnancy are associated with higher risk of SGA. In some countries iron supplementation is not recommended during pregnancy except in the case of anemia. Based on the results of this study, researchers suggest that all women should be screened for iron deficiency early in pregnancy using more specific measurements, and should be offered more personal and helpful advice on improving iron status through diet and supplements.  

Nisreen A. Alwan, Janet E. Cade, Harry J. McArdle, Darren C. Greenwood, Helen E. Hayes and Nigel A. B. Simpson. Maternal iron status in early pregnancy and birth outcomes: insights from the Baby's Vascular health and Iron in Pregnancy study. British Journal of Nutrition, available on CJO2015. doi:10.1017/S0007114515001166.

Impact of iron deficiency on exercise performance in women of reproductive age

Impact of iron deficiency on exercise performance in women of reproductive age 

At a GlanceA new meta-analysis has shown that women athletes, of reproductive age, who take iron supplements, experience a significant improvement in exercise performance. Read more about this research below.

Iron deficiency anemia is a common form of anemia and is a health risk for many women of reproductive age. Iron is an important component of hemoglobin in red bloods cells necessary to transport oxygen to tissues throughout the body. Iron deficiency occurs when iron requirements or losses exceed iron intake resulting in reduced tissue levels and deficient iron stores. Without adequate iron, blood is unable to efficiently transport oxygen contributing to fatigue, lethargy, and poor physical functioning.

Female athletes have a higher risk of this type of anemia due to dietary deficiencies, losses from blood and other bodily fluids, and reduced absorption due to exercised induced inflammation. Previous studies have suggested that low iron levels may impair exercise performance.

A study published in the Journal of Nutrition has found that women athletes of childbearing age with iron deficient anemia who supplement with iron experience a marked improved in exercise performance. Researchers performed a systematic review and analysis of the effect of iron supplementation and exercise performance of women in childbearing years utilizing randomized controlled trials that measured exercise outcomes to daily oral iron supplementation vs. control. 

Iron supplementation improved women's exercise performance, in terms of both the highest level they could achieve at 100% exertion (maximal capacity) and their exercise efficiency at a submaximal exertion. Anemic and iron deficient women who received iron were better able to perform a given exercise using a lower heart rate and at a higher efficiency than women who were not taking an iron supplement.

This study helps establish evidence that iron deficiency impairs exercise performance in women and may help better establish the beneficial effects of iron supplementation on exercise performance in women, and the general health and well-being of women in the general population. However, additional studies/ evidence may be required to further clarify the effects of iron on other exercise variables, and for other functional outcomes, such as work performance, productivity, and potential adverse effects.

Pasricha SR, Low M, Thompson J, Farrell A, De-Regil LM. Iron Supplementation Benefits Physical Performance in Women of Reproductive Age: A Systematic Review and Meta-Analysis. Journal of Nutrition, 2014; DOI: 10.3945/jn.113.189589