Iron status in late pregnancy is inversely associated with birth weight in Colombia

Associations of maternal serum concentration of iron-related indicators with birth outcomes in Chinese: a pilot prospective cohort study

BACKGROUND

Previous studies of maternal iron and birth outcomes have been limited to single indicators that do not reflect the comprehensive relationship with birth outcomes. We aimed to investigate the relationship between maternal iron metabolism and neonatal anthropometric indicators using comprehensive iron-related indicators.

METHODS

A total of 914 Chinese mother-child dyads were enrolled in this prospective study. Subjects' blood samples were collected at ≤ 14 weeks of gestation. Serum concentrations of iron-related indicators were measured by enzyme-linked immunosorbent assay (ELISA). Femur length was measured by B-ultrasound nearest delivery. Neonatal anthropometric indicators were collected from medical records.

RESULTS

After adjustment for potential covariates, higher iron (per one standard deviation, SD increase) was detrimentally associated with - 0.22 mm lower femur length, whereas higher transferrin (per one SD increase) was associated with 0.20 mm higher femur length. Compared with normal subjects (10th-90th percentiles), subjects with extremely high (> 90th percentile) iron concentration were detrimentally associated with lower femur length, birth weight, and chest circumference, and a higher risk of low birth weight, LBW (HR: 3.92, 95%CI: 1.28, 12.0). Subjects with high concentration of soluble transferrin receptor, sTFR and transferrin (> 90th percentile) were associated with higher femur length. Subjects with low concentration of iron and ferritin concentrations (< 10th percentile) were associated with a higher risk of LBW (HR: 4.10, 95%CI: 1.17, 14.3) and macrosomia (HR: 2.79, 95%CI: 1.06, 7.35), respectively.

CONCLUSIONS

Maternal iron overload in early pregnancy may be detrimentally associated with neonatal anthropometric indicators and adverse birth outcomes.

Maternal Iron Deficiency and Environmental Lead (Pb) Exposure Alter the Predictive Value of Blood Pb Levels on Brain Pb Burden in the Offspring in a Dietary Mouse Model: An Important Consideration for Cumulative Risk in Development

Maternal iron deficiency (ID) and environmental lead (Pb) exposure are co-occurring insults that both affect the neurodevelopment of offspring. Few studies have investigated how ID affects brain-region-specific Pb accumulations using human-relevant Pb concentrations. Furthermore, how these Pb exposures impact blood and brain Fe levels remains unclear. Importantly, we also wanted to determine whether the use of blood Pb levels as a surrogate for the brain Pb burden is affected by underlying iron status. We exposed virgin Swiss Webster female mice to one of six conditions differing by iron diet and Pb water concentration (0 ppm, 19 ppm, or 50 ppm lead acetate) and used Inductively Coupled Plasma Mass Spectrometry to measure the maternal and offspring circulating, stored, and brain Pb levels. We found that maternal ID rendered the offspring iron-deficient anemic and led to a region-specific depletion of brain Fe that was exacerbated by Pb in a dose-specific manner. The postnatal iron deficiency anemia also exacerbated cortical and hippocampal Pb accumulation. Interestingly, BPb levels only correlated with the brain Pb burden in ID pups but not in IN offspring. We conclude that ID significantly increases the brain Pb burden and that BPb levels alone are insufficient as a clinical surrogate to make extrapolations on the brain Pb burden.

Maternal Iron Status Is Dynamic Throughout Pregnancy and Might Predict Birth Outcomes in a Sex Dependent Manner: Results from the Alberta Pregnancy Outcomes and Nutrition (APrON) Cohort Study

BACKGROUND

Developmental responses to nutrient deprivation may differ by fetal sex. Despite this, relationships between maternal prenatal iron biomarkers and birth outcomes when stratifying by offspring sex are poorly described, especially in healthy cohorts.

OBJECTIVES

This study aimed to determine associations between maternal iron biomarkers and birth weights (BWs) and birth head circumferences (BHCs) among female and male newborns to assess whether the potential predictive ability of iron biomarkers on birth outcomes differs by offspring sex.

METHODS

The Alberta Pregnancy Outcomes and Nutrition (APrON) cohort study recruited 2189 pregnant individuals from Calgary and Edmonton, Canada. Maternal blood was drawn at each trimester and 3 mo postpartum. Maternal serum ferritin (SF) concentrations were measured using chemiluminescent immunoassays and erythropoietin (EPO), hepcidin, and soluble transferrin receptor (sTfR) using enzyme-linked immunosorbent assays. Ratios of sTfR:SF and hepcidin:EPO were calculated and birth outcomes accessed through delivery records. Directed acyclic graphs informed multivariate regression models.

RESULTS

The risk of maternal iron deficiency increased throughout pregnancy because ∼61% showed depleted iron stores (SF < 15 μg/L) by the third trimester. Maternal hepcidin, SF, sTfR, and sTfR:SF concentrations changed across time (P < 0.01), and participants carrying female fetuses consistently (across 6 biomarkers) showed a lower iron status during the third trimester compared with those with male fetuses (P < 0.05). Higher maternal SF and hepcidin:EPO during the third trimester was associated with lower BWs in males (P = 0.006 for SF; P = 0.03 for hepcidin:EPO) and females (P = 0.02 for SF; P = 0.02 for hepcidin:EPO). There were additional inverse associations between BWs and third trimester maternal hepcidin (P = 0.03) and hemoglobin (P = 0.004) and between BHCs and maternal SF (second trimester; P < 0.05) and Hb (third trimester P = 0.02) but only in males.

CONCLUSIONS

Relationships between maternal iron biomarkers and BWs and BHCs may depend on the timing of pregnancy and offpsring sex. There was a high risk of third trimester iron storage depletion among generally healthy pregnant individuals.

Correlation between serum ferritin in early pregnancy and hypertensive disorders in pregnancy

Objective

To explore the correlation between serum ferritin (SF) in early pregnancy and the risk of hypertensive disorders in pregnancy (HDP).

Method

A retrospective cohort study was conducted on 43,421 pregnant women with singleton pregnancies who underwent antenatal checkups at Fujian Provincial Maternal and Child Health Hospital from January 2018 to December 2020. Based on pregnancy records, women were classified as non-hypertensive, having gestational hypertension, preeclampsia and preeclampsia with severe features according to the degree of the disease. General baseline data, and SF levels in the early (up to 12 gestational weeks) and late (after 28  weeks of gestation) stages of pregnancy were collected. The significance of the characteristic variables was assessed using a random forest algorithm, and the correlation between early pregnancy SF levels and the incidence of HDP was further analyzed using logistics regression adjusted for confounders. A generalized additive model (GAM) was fitted to a smoothed graph of the relationship between early pregnancy SF levels and HDP, and a threshold effect analysis was performed to find the threshold values of early pregnancy SF for iron supplementation therapy.

Result

A total of 30,703 pregnant women were included. There were 1,103 women who were diagnosed with HDP. Of them, 418 had gestational hypertension, 12 had chronic hypertension without SPE, 332 - preeclampsia and 341 women had preeclampsia with severe features. Levels of SF in early and late pregnancy were significantly higher (p < 0.001) in women with HDP compared to non-hypertensive women and the difference was more pronounced in early pregnancy. The random forest algorithm showed that early pregnancy SF was more effective in predicting HDP compared to late pregnancy SF levels and was also an independent risk factor for HDP (adjusted odds ratio (AOR) = 1.07, 95% CI [1.05,1.09]) after correction for confounding factors. Early pregnancy SF >64.22  mg/l was associated with higher risk of developing hypertensive disorders.

Conclusion

Risk of pregnancy-related hypertensive disorders increases with increasing early pregnancy SF levels. SF levels may therefore be used to further develop guidelines for iron supplementation therapy in pregnant women.

The effect of maternal anaemia on low birth weight among newborns in Northwest Ethiopia

Low birth weight is an indicator of maternal-related multifactorial problems such as malnutrition, illness, and work overload. As a result, low birth weight is associated with maternal anaemia, and both of them were significant public health issues in developing nations. Low birth weight and anaemia are caused by insufficient nutrient intake, which is especially severe during pregnancy. So, this study aimed to assess the effect of maternal anaemia during the late trimester on low birth weight among newborns in Northwest Ethiopia. A systematic random sampling technique was used to select 211 participants for the primary data collection. Face-to-face interviews were used to collect data, while blood samples were collected using standard operating procedures. For further analysis, the data file was imported into Stata version 16 (MP) software. The binary logistic regression model was used to investigate significant factors related to low birth weight. Finally, the statistical significance of the variables was determined using a p value of ≤ 0.05. The prevalence of anaemia among pregnant women in the late trimester and newborns was 34 (16.11%, 95% CI: 11.42, 21.78) and 64 (30.33%, 95% CI: 24.20, 37.01), respectively. The mean ± standard deviation of the newborn babies' weight was 3.19 ± 0.49 kg. The proportion of low birth weight among newborns was 26 (12.32%, 95% CI: 8.20, 17.53%). The independent effect of anaemia on low birth weight was 4.19 times while all other factors were constant (COR = 4.19, 95% CI: 1.70, 10.30). Maternal educational status [unable to read and write (AOR = 10.94, 95% CI: 1.74, 68.58) and attained secondary education (AOR = 8.06, 95% CI: 1.53, 42.36)], and maternal anaemia (AOR = 3.51, 95% CI: 1.29, 9.55) were associated with low birth weight after adjusting with all other variables. In this study, the proportion of low birth weight was high. Here, maternal anaemia alone had a significant independent role in the development of low birth weight. Maternal education status and anaemic conditions were associated with low birth weight among newborns. Early detection and treatment of maternal anaemia during pregnancy is crucial with the usual nutritional-related care.

Association Between Serum Ferritin Concentration and Risk of Adverse Maternal and Fetal Pregnancy Outcomes: A Retrospective Cohort Study

OBJECTIVE

This study evaluated the associations of serum ferritin (SF) concentration during pregnancy with the risk of adverse maternal and fetal pregnancy outcomes.

METHODS

We conducted a retrospective study of 2327 pregnant women from 2015 to 2020 in Guangdong, China. SF concentrations were measured at 16-18th and 28-32th week of gestation. Logistic regression models were applied to estimate the association between SF concentration and the risk of adverse pregnancy outcomes.

RESULTS

After multivariable adjustment, the odds ratio (OR) of the highest quartile of SF concentration at 16-18th week of gestation was 1.43 (95% confidence interval [CI]: 1.09, 1.89) for gestational diabetes mellitus (GDM) and 1.79 (95% CI: 1.15, 2.79) for small for gestational age (SGA) when compared with the lowest quartile. At 28-32th week of gestation compared with the lowest quartile, women with SF in the highest quartile had an increased risk of SGA (OR: 1.62; 95% CI: 1.01, 2.62). Moreover, the lowest quartile of SF concentration decreased risk of SGA by 90% (95% CI: 0.01, 0.80) when compared with the highest quartile among pregnancy women with GDM.

CONCLUSION

Elevated SF concentrations increased the risk of GDM and SGA during pregnancy. Maintaining an appropriately low level of maternal SF at 28-32th week of gestation in women with GDM could reduce the risk of SGA.