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Impact of iron supplements on non-anaemic pregnant women and foetal outcomes

Posted:  Friday, July 22, 2016

Effect of iron supplements on non-anaemic pregnant women and foetal outcomes

Iron supplements are routinely prescribed for women during pregnancy irrespective of the initial iron or haemoglobin status. Recent studies have indicated that iron supplementation in mild or non-anaemic pregnant women may stimulate intrauterine oxidative stress, which may manifest as growth restrictions of the foetus, raised blood pressure, and low-birth-weight infants. A new study published in the journal of Public Health Nutrition assessed the association between haemoglobin status in the first trimester (Hb1) and oxidative stress, and whether this association had an impact on birth outcomes.

The cross-sectional cohort study enrolled 100 pregnant women aged 17–40 years based on their Hb1 levels. Forty women had low Hb1 levels (<110 g/L), and 60 women had high Hb1 levels (≥120 g/L). These women were administered iron supplements in the 2nd and 3rd trimesters irrespective of their Hb1 levels. Blood samples were collected from the women; cord blood was collected from the infants at birth, for Hb analysis.

Approximately 70% of the women adhered to the treatment with iron supplements. Low-birth-weight (LBW) infants were reported to be born to 25% of the women with low/normal Hb1 levels and to 38% of women with high Hb1 levels. An assessment of oxidative stress parameters revealed that women with high Hb1 levels had lower activity of paraoxonase-1 (PON-1), an important anti-oxidative enzyme. Similar results were seen in the cord blood samples containing high levels of Hb. Higher lipid peroxide (LPO) activity was found in women with high Hb1 levels but not in the cord blood samples. Women who delivered LBW infants had lower activity of PON-1 and LPO compared to those who delivered normal birth infants.

This study included a small number of pregnant women. Moreover, the study assessed the oxidative stress parameters during the 1st trimester, rather than during all trimesters, and from the cord blood. Furthermore, the study population did not comprise infants from different backgrounds, and this may have introduced bias in the results.

The study concluded that routine iron supplementation in women with high Hb1 levels was linked with increased oxidative stress, as evidenced by lower activity of PON-1 and LPO during the first trimester. Lower circulating anti-oxidative enzymes could serve as an early indicator of oxidative stress, which could have an adverse effect on the birth weight of infants.

News source - Shastri L, Pammal RS, Mani I, Thomas T, Kurpad AV. Oxidative stress during early pregnancy and birth outcomes. Public health nutrition. 2016 Jun 3:1-6.