The Association between Maternal Dietary Iron Intake during the First Trimester of Pregnancy with Pregnancy Outcomes and Pregnancy-Related Complications

Association between maternal iron status and the risk of pre-eclampsia: a case-control study

BACKGROUND AND OBJECTIVES

This study aimed to assess the associations of maternal iron status and placental iron transport proteins expression with the risk of pre-eclampsia (PE) in Chinese pregnant women.

METHODS AND STUDY DESIGN

A total of 94 subjects with PE and 112 healthy pregnant women were enrolled. Fasting blood samples were collected to detect maternal iron status. The placenta samples were collected at delivery to detect the mRNA and protein expression of divalent metal transporter 1 (DMT1) and ferroportin-1 (FPN1). Logistic analysis was used to explore the associations of maternal iron status with PE risk. The associations of placental iron transport proteins with maternal iron status were explored.

RESULTS

After adjusting for covariates, dietary total iron, non-heme iron intake and serum hepcidin were negatively associated with PE, with adjusted ORs (95%CIs) were 0.40 (0.17, 0.91), 0.42 (0.18, 0.94) and 0.02 (0.002, 0.13) for the highest versus lowest tertile, respectively. For the highest tertile versus lowest tertile, serum iron (4.08 (1.58, 10.57)) and ferritin (5.61 (2.36, 13.31)) were positively associated with PE. The mRNA expressions and protein levels of DMT1 and FPN1 in placenta were up-regulated in the PE group (p < 0.05). The mRNA expressions of DMT1 and FPN1 in placenta showed a negative correlation with the serum hepcidin (r = -0.71, p < 0.001; r = -0.49, p < 0.05).

CONCLUSIONS

In conclusion, the maternal iron status were closely associated with PE risk, placental DMT1 and FPN1 were upregulated in PE which may be a promising target for the prevention of PE.

The association between dietary mineral intake and the risk of preeclampsia in Chinese pregnant women: a matched case-control study

Previous studies on the relationship between dietary minerals and preeclampsia (PE) have given inconsistent results. The aim of this study was to further clarify the relationship between dietary minerals intake and PE in Chinese pregnant women. In this study, 440 pairs of hospital-based preeclamptic and healthy women were matched 1:1. Dietary intake was obtained through a 78-item semi-quantitative food frequency questionnaire. Multivariate conditional logistic regression was used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs). Restricted cubic splines were plotted to evaluate the dose-response relationship between dietary minerals intake and PE. This study found significant inverse associations for dietary intake of calcium, magnesium, phosphorus, iron, copper, manganese and zinc and the risk of PE in both univariate and multivariate models (all P- trend < 0.05). After adjusting for possible confounders, compared with the lowest quartile, the odds ratio of the highest quartile was 0.74 (95% CI 0.56-0.98) for calcium, 0.63 (95% CI 0.42-0.93) for magnesium, 0.45 (95% CI 0.31-0.65) for phosphorus, 0.44 (95% CI 0.30-0.65) for iron, 0.72 (95% CI 0.53-0.97) for copper, 0.66 (95% CI 0.48-0.91) for manganese and 0.38 (95% CI 0.25-0.57) for zinc. In addition, a reverse J-shaped relationship between dietary minerals intake and PE risk was observed (P-overall association < 0.05). In Chinese pregnant women, a higher intake of dietary minerals, including calcium, magnesium, phosphorus, copper, iron, manganese, and zinc was associated with a lower odds of PE.

Prenatal environment and developmental trajectories: the intrauterine growth restriction

The prenatal environment is of fundamental importance for the fetus, as the fetus is particularly susceptible to environmental influences while in utero, and several prenatal adversities may constitute a risk factor for fetal growth and child development. Intrauterine growth restriction (IUGR) refers to a pregnancy complication involving the inadequate growth of the fetus in utero, with potential programming consequences on the children's brain-behavior development. In this narrative review we will discuss the most recent literature about IUGR children, including their development and their relationship with the prenatal and postnatal environment. In particular, as an attempt to an adaptive response to intrauterine changes, the brain development of IUGR fetuses follows abnormal developmental pathways, which likely has cascade effects on the future neurodevelopmental outcomes of the children. Cognitive and motor functions are in fact impaired, as well as IUGR children present, across studies, poor socio-emotional abilities and a greater risk for internalizing and externalizing behavior problems. The current work also highlights how the postnatal environment, and in particular parental care, has an important role in IUGR development, acting as a protective factor, or otherwise increasing their constitutional vulnerabilities. Overall, this narrative review has important implications for clinical practice, suggesting the need for long-term follow-up care with IUGR children and strategies supporting parent-child interactions as well.

Maternal heme-enriched diet promotes a gut pro-oxidative status associated with microbiota alteration, gut leakiness and glucose intolerance in mice offspring

Maternal environment, including nutrition and microbiota, plays a critical role in determining offspring's risk of chronic diseases such as diabetes later in life. Heme iron requirement is amplified during pregnancy and lactation, while excessive dietary heme iron intake, compared to non-heme iron, has shown to trigger acute oxidative stress in the gut resulting from reactive aldehyde formation in conjunction with microbiota reshape. Given the immaturity of the antioxidant defense system in early life, we investigated the extent to which a maternal diet enriched with heme iron may have a lasting impact on gut homeostasis and glucose metabolism in 60-day-old C3H/HeN mice offspring.

As hypothesized, the form of iron added to the maternal diet differentially governed the offspring's microbiota establishment despite identical fecal iron status in the offspring. Importantly, despite female offspring was unaffected, oxidative stress markers were however higher in the gut of male offspring from heme enriched-fed mothers, and were accompanied by increases in fecal lipocalin-2, intestinal para-cellular permeability and TNF-α expression. In addition, male mice displayed blood glucose intolerance resulting from impaired insulin secretion following oral glucose challenge. Using an integrated approach including an aldehydomic analysis, this male-specific phenotype was further characterized and revealed close covariations between unidentified putative reactive aldehydes and bacterial communities belonging to Bacteroidales and Lachnospirales orders.

Our work highlights how the form of dietary iron in the maternal diet can dictate the oxidative status in gut offspring in a sex-dependent manner, and how a gut microbiota-driven oxidative challenge in early life can be associated with gut barrier defects and glucose metabolism disorders that may be predictive of diabetes development.

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Maternal heminic vs. non-heminic iron intake differentially and persistently imprints the offspring's fecal microbiota.

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Males from heme-fed dams exhibit increased gut lumen reactive aldehydes in absence of direct dietary exposure to heme iron.

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Some of the increased reactive aldehydes closely covariated with Orders belonging to Bacteroidales and Lachnospirales.

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Maternal exposure to dietary heme iron impairs gut barrier and glucose tolerance in male offspring.

Iron Metabolism in Normal and Pathological Pregnancies and Fetal Consequences

Iron is required for energy production, DNA synthesis, and cell proliferation, mainly as a component of the prosthetic group in hemoproteins and as part of iron-sulfur clusters. Iron is also a critical component of hemoglobin and plays an important role in oxygen delivery. Imbalances in iron metabolism negatively affect these vital functions. As the crucial barrier between the fetus and the mother, the placenta plays a pivotal role in iron metabolism during pregnancy. Iron deficiency affects 1.2 billion individuals worldwide. Pregnant women are at high risk of developing or worsening iron deficiency. On the contrary, in frequent hemoglobin diseases, such as sickle-cell disease and thalassemia, iron overload is observed. Both iron deficiency and iron overload can affect neonatal development. This review aims to provide an update on our current knowledge on iron and heme metabolism in normal and pathological pregnancies. The main molecular actors in human placental iron metabolism are described, focusing on the impact of iron deficiency and hemoglobin diseases on the placenta, together with normal metabolism. Then, we discuss data concerning iron metabolism in frequent pathological pregnancies to complete the picture, focusing on the most frequent diseases.

The role of nutrition in the development and management of gestational diabetes among Iranian women: a systematic review and meta-analysis

Purpose

We aimed to review existing evidence on nutrition associations with gestational diabetes mellitus (GDM) development and management among Iranian women.

Methods

Web of Science, PubMed, Scopus, SID, and Magiran were searched up to August 2020. Observational studies on associations between circulatory markers of vitamins and minerals, dietary intakes, and GDM and clinical trials of the effects of nutritional supplementations or dietary modifications on management or prevention of GDM among Iranian women were selected.

Results

We reviewed 49 publications. Pooled analyses revealed that GDM women had lower serum vitamin D (-8.31 nmol/l (95% CIs= -14.4, -2.19), higher serum iron (26.2 μg/dl (95% CIs= 2.52, 49.8), ferritin (24.1 ng/ml (95% CIs= 15.0, 33.4), and haemoglobin (1.14 g/dl (95% CIs: 0.32, 1.96) levels than non-GDM women. Single studies found the inverse associations of the Mediterranean diet, dietary approaches to stop hypertension diet, plant-based dietary index, and the direct associations of dietary acid load and dietary inflammatory index with the odds of GDM. Vitamin D supplementation early in pregnancy prevented GDM in two clinical trials. In two studies, iron supplementation's effect on GDM in non-anemic women was inconsistent. Pooled analyses of probiotic supplementation in women with GDM showed no significant impact on maternal glycemia.

Conclusions

Vitamin D supplementation early in pregnancy may reduce the incidence of GDM. There is no compelling evidence that vitamin D or probiotics can help with GDM management. There is currently inadequate data to recommend a specific dietary pattern to prevent GDM in Iranian women.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-021-00944-7.