Centre of Excellence for Nutrition, North-West University, Potchefstroom, South Africa.
Department of Life and Consumer Sciences, University of South Africa, Johannesburg, South Africa.
PLoS One. 2019 Sep 3;14(9):e0221299. doi: 10.1371/journal.pone.0221299. eCollection 2019.
Recent studies are suggesting a U-shaped relationship between antenatal iron exposure and birth outcomes. Little is known about the iron status and associated birth outcomes of pregnant women in South Africa. Our aim was to assess iron status at early, mid- and late pregnancy, and to determine associations with gestational age and birth weight in women in Johannesburg, South Africa.
In this prospective study of 250 pregnant women, we measured haemoglobin, biomarkers of iron status and inflammation at <18, 22 and 36 weeks of gestation, plus birth weight and gestational age at delivery. Associations of anaemia and iron status with birth outcomes were determined using regression models adjusted for confounders.
At enrolment, the prevalence of anaemia, iron depletion (ID) and iron deficiency erythropoiesis (IDE) was 29%, 15% and 15%, respectively, and increased significantly with pregnancy progression. Anaemia and ID at 22 weeks, as well as IDE at 36 weeks were associated with higher birth weight (β = 135.4; 95% CI: 4.8, 266.1 and β = 205.4; 95% CI: 45.6, 365.1 and β = 178.0; 95% CI: 47.3, 308.7, respectively). Women in the lowest ferritin quartile at 22 weeks gave birth to babies weighing 312 g (95% CI: 94.8, 528.8) more than those in the highest quartile. In contrast, IDE at 22 weeks was associated with a higher risk for premature birth (OR: 3.57, 95% CI: 1.24, 10.34) and women in lower haemoglobin quartiles at <18 weeks had a shorter gestation by 7 days (β = -6.9, 95% CI: -13.3, -0.6) compared to those in the highest quartile.
Anaemia, ID and IDE prevalence increased during pregnancy despite routine iron supplementation. ID and anaemia at mid-pregnancy were associated with higher birth weight, while IDE was associated with premature birth. These results suggest that current antenatal screening and supplementation practices in South Africa need to be revisited.
最近的研究表明，产前铁暴露与出生结局之间存在 U 形关系。关于南非孕妇的铁状况及其与出生结局的关系知之甚少。我们的目的是评估约翰内斯堡孕妇在妊娠早期、中期和晚期的铁状况，并确定其与胎龄和出生体重的关系。
在这项对 250 名孕妇的前瞻性研究中，我们在妊娠<18、22 和 36 周时测量了血红蛋白、铁状态和炎症的生物标志物，以及分娩时的出生体重和胎龄。使用调整了混杂因素的回归模型确定了贫血和铁状态与出生结局的关联。
在入组时，贫血、铁缺乏（ID）和缺铁性红细胞生成（IDE）的患病率分别为 29%、15%和 15%，且随着妊娠进展显著增加。22 周时的贫血和 ID，以及 36 周时的 IDE 与较高的出生体重相关（β=135.4；95%CI：4.8，266.1 和β=205.4；95%CI：45.6，365.1 和β=178.0；95%CI：47.3，308.7）。22 周时铁蛋白最低四分位数的孕妇所生婴儿比最高四分位数的孕妇重 312 克（95%CI：94.8，528.8）。相比之下，22 周时的 IDE 与早产风险增加相关（OR：3.57，95%CI：1.24，10.34），而 18 周时血红蛋白较低四分位数的孕妇的妊娠时间比最高四分位数的孕妇短 7 天（β=-6.9，95%CI：-13.3，-0.6）。
尽管常规补充铁剂，但在妊娠期间贫血、ID 和 IDE 的患病率仍在增加。妊娠中期的 ID 和贫血与较高的出生体重相关，而 IDE 与早产相关。这些结果表明，南非目前的产前筛查和补充实践需要重新考虑。
