Association of maternal iron deficiency anemia with the risk of gestational diabetes mellitus: a meta-analysis

The epidemiology of gestational diabetes, gestation hypertension, and anemia in North Palestine from 2018 to 2020: A retrospective study

BACKGROUND

In Palestine, women face a challenging environment and a demanding lifestyle, which puts them at a higher risk of experiencing complications during pregnancy. This study aimed to examine the risk factors linked with abnormal hemoglobin (Hb) levels, gestational diabetes (GD), and gestational hypertension (GH) among pregnant women. The results was compared between women residing in cities or villages areas and those in refugee camps.

METHODS

Medical records (N = 7889) for pregnant women at primary healthcare centers in the North West Bank were reviewed for sociodemographic and medical data along with the reported fasting blood sugar, hemoglobin, and blood pressure in the first and second trimesters from July 2018 to July 2020. However, only 6640 were included in the analysis as 1249 were excluded for having multiple pregnancy or lost to follow up. Complications and risk factors were defined according to the available global guidelines. Then, descriptive analysis was used to show the percentages of different risk factors and complications among them. The correlation between the several characteristics and variables with these complications was assessed by calculating the odds ratios (OR) using logistic regression. P-values of <0.05 were considered significant.

RESULTS

The prevalence of adolescent pregnancy was the highest among women living in rural areas (9.8%) and grand multigravidity among refugee women (22%). The overall prevalence of anemia was higher in the second-trimester (16.2%) than in the first-trimester (11.2%), with anemic women in the first-trimester being more likely to be anemic in the second-trimester (OR = 8.223, P-value<0.001). Although anemia was less common in the first-trimester among refugees than among women living in urban areas (OR = 0.768, P-value = 0.006), it was more prevalent in the second-trimester (OR = 1.352, P-value<0.001). Moreover, refugee women were at lower risk than women living in urban areas of having GD (OR = 0.687, P-value<0.001) and diabetes mellitus (OR = 0.472, P-value<0.001) in the second-trimester. GH was associated with GD (OR = 1.401, P-value = 0.003) and DM (OR = 1.966, P-value<0.001).

CONCLUSION

The findings of this study provide evidence-based data on the considerable prevalence of pregnancy complications, anemia, GD, and GH among Palestinian pregnant women living in the north of the West Bank. Multi gravida, gestational age, Hb levels, and the type of settings were strong predictors of pregnancy complications. Therefore, a national plan is needed to ensure adequate maternal care for all, especially disadvantaged women, those in rural areas and refugee camps.

Maternal and Neonatal Outcomes of Iron Deficiency Anemia: A Retrospective Cohort Study

INTRODUCTION

Understanding the outcomes of anemia in pregnancy is critical. Since no study has been conducted regarding the maternal and neonatal outcomes of iron-deficiency anemia in Hormozgan province of Iran, this study aims to assess the maternal and neonatal outcomes of iron-deficiency anemia in women who gave birth in Hormozgan province from January 2020 to January 2022.

METHODS

 We retrospectively assessed all singleton pregnant women who gave birth at a tertiary hospital in Bandar Abbas, Hormozgan province, Iran, for two years. We divided all women into iron-deficiency anemic and non-iron-deficiency anemic women. Iron-deficiency anemia was defined as hemoglobin less than 10.5 mg/dl at the time of admission without any other hemoglobinopathy, such as sickle cell anemia or thalassemia. Using electronic patient records, data were extracted from the Iranian Maternal and Neonatal Network (IMaN Net), a valid national system. Since the information of birth under 24 weeks of gestation is not recorded in this system, we excluded all deliveries under 24 weeks of gestation. The outcome measures of the study were demographic factors (age, education, residency place, access to prenatal care, smoking), obstetrical factors (parity, labor induction, fetal presentation, mode of delivery), and maternal and neonatal outcomes (the incidence of preeclampsia, gestational diabetes, placenta abruption, postpartum hemorrhage, maternal need for blood transfusion, maternal need for intensive care unit, preterm birth, low birth weight, intrauterine growth retardation, birth asphyxia, stillbirth, and neonatal intensive care admission). Chi-square tests were used to compare differences between iron-deficiency anemic and non-iron-deficiency anemic women. Logistic regression models were used to assess the effect of iron-deficiency anemia on maternal and neonatal outcomes. The result was presented as odds ratio (OR) or adjusted odds ratio (aOR) after adjusting for covariates and a 95% confidence interval (CI).  Results: The incidence of iron-deficiency anemia was 2.97%. Education and residency were among the demographic factors that differed significantly between groups. Iron-deficiency anemia was more frequent in those with higher education and women who lived in rural areas. In terms of obstetrical factors, method of delivery was the only significantly different factor between groups. Iron-deficiency anemic mothers had substantially more instrumental deliveries than non-iron-deficiency anemic mothers (4.3% vs. 0.8%), while the incidence of cesarean section was lower. Based on logistic regression in terms of maternal and neonatal outcomes, iron-deficiency anemic women had a substantially higher risk of the need for maternal blood transfusion (aOR: 6.54, 95%CI: 4.72-8.15), postpartum hemorrhage (aOR: 1.54, 95%CI: 0.71-2.11), preterm birth (aOR: 0.98, 95%CI: 0.45-1.13), low birth weight (aOR: 1.04, 95%CI: 0.78-2.01), intrauterine growth retardation (aOR: 1.30, 95%CI: 0.99-2.10), and neonatal intensive care admission (aOR: 1.06, 95%CI: p.52-2.72), after adjusting for educational level, residency place, and method of delivery.

CONCLUSIONS

Despite the higher incidence of postpartum hemorrhage and maternal blood transfusion, we found no increase in maternal intensive care unit admission risk. Regarding neonatal outcomes, iron-deficiency anemia was linked to preterm birth, low birth weight, intrauterine growth retardation, and neonatal intensive care admission.

Association of a pro-inflammatory diet and gestational diabetes mellitus with maternal anemia and hemoglobin levels during pregnancy: a prospective observational case-control study

Anemia is prevalent in pregnant women, and the causes include inadequate diet, increased demand for iron, and inflammation. We hypothesized that gestational diabetes mellitus (GDM) and hepcidin-related gene polymorphisms may contribute to maternal anemia and that an anti-inflammatory diet can alleviate this negative effect. The aim of this study was to investigate the association of an inflammatory diet, GDM, and single nucleotide polymorphisms (SNPs) in hepcidin-related genes, which are key regulators of iron, with maternal anemia. This was a secondary data analysis of a prospective prenatal diet and pregnancy outcome study in Japan. The Energy-Adjusted Dietary Inflammatory Index was calculated using a brief self-administered diet history questionnaire. We analyzed 121 SNPs in 4 genes: TMPRS6 (43 SNPs), TF (39 SNPs), HFE (15 SNPs), and MTHFR (24 SNPs). Multivariate regression analysis was conducted to determine the association between the first variable and maternal anemia. The prevalence of anemia in first, second, and third trimesters were 5.4%, 34.9%, and 45.8%, respectively. The pregnant women with GDM had a significantly higher incidence of moderate anemia than those without GDM (40.0% vs. 11.4%, P = .029). In multivariate regression analysis, Energy-adjusted Dietary Inflammatory Index (β = -0.057, P = .011) and GDM (β = -0.657, P = .037) were significantly associated with hemoglobin levels during the third trimester. Using Stata's qtlsnp command, TMPRSS6 rs2235321 was found to be associated with hemoglobin levels during the third trimester. These results indicate that inflammatory diets, GDM, and TMPRSS6 rs2235321 polymorphism are associated with maternal anemia. This result suggests that a pro-inflammatory diet and GDM are associated with maternal anemia.

Impact of iron supplementation on gestational diabetes mellitus: A literature review

Gestational diabetes mellitus (GDM) is a common complication of pregnancy, affecting 14% of pregnancies worldwide, and the prevention of pathological hyperglycaemia during pregnancy is meaningful for global public health. The role of iron supplementation in the progression of GDM has been of significant interest in recent years. Iron is a micronutrient that is vital during pregnancy; however, given the toxic properties of excess iron, it is probable that prophylactic iron supplementation will increase the risk of adverse pregnancy outcomes, including GDM. It is critical to clarify the effect of iron supplementation on the risk of GDM. Therefore, in this review, we comprehensively assess the role of iron in pregnancy. This review aimed to analyse the necessity of iron supplementation and maintenance of iron homeostasis during pregnancy, particularly reviewing the role and function of iron in beta cells and examining the mechanisms of excess iron contributing to the pathogenesis of GDM. Moreover, we aimed to discuss the association of haemoglobin and ferritin with GDM and identify priority areas for research.

Evaluation of first and second trimester maternal thyroid profile on the prediction of gestational diabetes mellitus and post load glycemia

Maternal thyroid alterations have been widely associated with the risk of gestational diabetes mellitus (GDM). This study aims to 1) test the first and the second trimester full maternal thyroid profile on the prediction of GDM, both alone and combined with non-thyroid data; and 2) make that prediction independent of the diagnostic criteria, by evaluating the effectiveness of the different maternal variables on the prediction of oral glucose tolerance test (OGTT) post load glycemia. Pregnant women were recruited in Concepción, Chile. GDM diagnosis was performed at 24-28 weeks of pregnancy by an OGTT (n = 54 for normal glucose tolerance, n = 12 for GDM). 75 maternal thyroid and non-thyroid parameters were recorded in the first and the second trimester of pregnancy. Various combinations of variables were assessed for GDM and post load glycemia prediction through different classification and regression machine learning techniques. The best predictive models were simplified by variable selection. Every model was subjected to leave-one-out cross-validation. Our results indicate that thyroid markers are useful for the prediction of GDM and post load glycemia, especially at the second trimester of pregnancy. Thus, they could be used as an alternative screening tool for GDM, independently of the diagnostic criteria used. The final classification models predict GDM with cross-validation areas under the receiver operating characteristic curve of 0.867 (p<0.001) and 0.920 (p<0.001) in the first and the second trimester of pregnancy, respectively. The final regression models predict post load glycemia with cross-validation Spearman r correlation coefficients of 0.259 (p = 0.036) and 0.457 (p<0.001) in the first and the second trimester of pregnancy, respectively. This investigation constitutes the first attempt to test the performance of the whole maternal thyroid profile on GDM and OGTT post load glycemia prediction. Future external validation studies are needed to confirm these findings in larger cohorts and different populations.

Iron Supplementation in Pregnancy and Risk of Gestational Diabetes: A Narrative Review

Pregnant women frequently supplement their diets with iron to treat any cryptic anemia, on the assumption that if anemia is not present, there will be no negative consequences. However, in women who are already iron-replete, it has been suggested that this can lead to iron overload and an increased risk of certain pregnancy complications. One such complication is gestational diabetes. Fourteen clinical trials, case-control or cohort studies (found using Pubmed/Scopus/Web of Science) have investigated links between iron supplementation in pregnancy and risk of gestational diabetes, several of them finding significant associations with increased risk. Potential mechanisms include increased oxidative stress leading to insulin resistance and inadequate compensatory insulin secretion. Current evidence suggests that dietary supplementation with iron in pregnancy may increase a pregnant woman's chance of developing gestational diabetes, although available evidence is somewhat contradictory, and the magnitude of any increased risk appears relatively small. Meta-analyses have suggested the presence of significant heterogeneity in results between studies, urging a degree of caution in interpreting these results. It is currently suggested that advice to pregnant women about whether to supplement their diets with iron or not should consider both their current iron status and their other established risk factors for gestational diabetes.

Prothrombotic state and calcium deficiency in early pregnancy are risk factors for gestational diabetes mellitus: a retrospective cohort study

OBJECTIVES

To investigate whether the prothrombotic state (PTS), calcium deficiency and iron deficiency anemia (IDA) in early pregnancy is associated with the risk of gestational diabetes mellitus (GDM).

METHODS

We conducted a retrospective cohort study, including consecutive pregnant women tested for PTS, calcium deficiency and IDA before 20 weeks' gestation between September 1, 2017 and March 21, 2021. For routine prenatal care, pregnant women underwent a 75-g oral glucose tolerance test (OGTT) to make a GDM diagnosis during 24-28 weeks of gestation. Testing data and relevant clinical information were obtained from Shenzhen Baoan Women's and Children's Hospital. To estimate GDM risk of exposures (PTS, calcium deficiency and IDA) in early pregnancy, we used logistic regression to obtain odds ratio (OR) adjusted for maternal age, parity, family history of diabetes and pre-pregnancy body mass index.

RESULTS

The cohort included 8396 pregnant women with complete data of exposures and GDM outcomes. Baseline characteristics were not comparable between exposure and control groups. PTS (adjusted OR 2.38, 95% CI 1.61-3.52) or calcium deficiency (adjusted OR 1.23, 95% CI 1.02-1.49) in early pregnancy was independently associated with increased GDM risk after adjusting covariates. There was no significant association between IDA status and GDM risk (adjusted OR 0.86, 95% CI 0.63-1.18).

CONCLUSIONS

PTS and calcium deficiency in early pregnancy may be independent risk factors of GDM. These findings need further validation in well-designed prospective cohorts.

The Impact of Nutritional Supplementation During Pregnancy on the Incidence of Gestational Diabetes and Glycaemia Control

The nutritional state before and throughout pregnancy has a critical impact on the women's health and the baby's development and growth. The release of placental hormones during pregnancy induces/ increases maternal insulin resistance and promotes nutrition utilization by the fetus. Gestational Diabetes Mellitus (GDM) is the most common medical complication in pregnancy and is associated with significant maternal and fetal morbidity. Several studies have examined the effect of physical activity, healthy eating, and various food supplements on the risk of developing gestational diabetes (GDM) and related outcomes. Among those, Myo-Inositol supplementation has shown encouraging results in the prevention of GDM. Maternal vitamin D deficiency has been associated with an elevated risk of GDM, and supplementation can improve glucose haemostasis by lowering fasting blood glucose, HbA1c, and serum insulin concentration. Probiotics modulate the gut microbiota leading to an improved glucose and lipid metabolism, which is proposed to reduce the risk of GDM. We aim to review the strength and limitation of the current evidence for using some nutritional supplements either as single agents or in combinations on the risk of developing GDM and on glycaemic control.

Maternal first trimester iron status and its association with obstetric and perinatal outcomes

PURPOSE

To assess the following in singleton pregnant women: (1) associations between first trimester iron deficiency and obstetric and perinatal outcomes, (2) overall first trimester iron status and (3) post-treatment iron status after intensified iron supplementation.

METHODS

A prospective cohort study was conducted with linkage of first trimester hemoglobin and plasma ferritin with obstetric and perinatal data from a hospital database. Blood sample data were obtained from a Danish University Hospital. The cohort was divided into groups according to ferritin and hemoglobin: (1) iron-deficient anemic (ferritin < 30 ng/mL and Hb < 110 g/L), (2) iron-deficient non-anemic (ferritin < 30 ng/mL and Hb ≥ 110 g/L), and (3) iron-replete non-anemic (ferritin 30-200 ng/mL and Hb ≥ 110 g/L). Obstetric and perinatal outcomes in each iron-deficient group were compared to the iron-replete non-anemic group using multivariable logistic regression. The effect of 4 weeks intensified iron supplementation on hemoglobin and ferritin was assessed by groupwise comparisons.

RESULTS

The cohort comprised 5763 singleton pregnant women, of which 14.2% had non-anemic iron deficiency, and 1.2% had iron-deficiency anemia. Compared to iron-replete non-anemic women, iron-deficient anemic women had a higher risk of gestational diabetes (aOR 3.8, 95% CI 1.4-9.0), and iron-deficient non-anemic women had a higher risk of stillbirth (aOR 4.0, 95% CI 1.0-14.3). In group 1 and 2, 81.5% and 67.7% remained iron-deficient after intensified iron supplementation.

CONCLUSION

Iron-deficiency anemia was associated with gestational diabetes, and non-anemic iron deficiency with stillbirth, although risk estimates were imprecise due to few events. Iron deficiency was present in 15.4% and often persisted despite 4 weeks intensified iron supplementation.

tRNA Biology in the Pathogenesis of Diabetes: Role of Genetic and Environmental Factors

The global rise in type 2 diabetes results from a combination of genetic predisposition with environmental assaults that negatively affect insulin action in peripheral tissues and impair pancreatic β-cell function and survival. Nongenetic heritability of metabolic traits may be an important contributor to the diabetes epidemic. Transfer RNAs (tRNAs) are noncoding RNA molecules that play a crucial role in protein synthesis. tRNAs also have noncanonical functions through which they control a variety of biological processes. Genetic and environmental effects on tRNAs have emerged as novel contributors to the pathogenesis of diabetes. Indeed, altered tRNA aminoacylation, modification, and fragmentation are associated with β-cell failure, obesity, and insulin resistance. Moreover, diet-induced tRNA fragments have been linked with intergenerational inheritance of metabolic traits. Here, we provide a comprehensive review of how perturbations in tRNA biology play a role in the pathogenesis of monogenic and type 2 diabetes.

High Prevalence of Gestational Diabetes Mellitus in Rural Tanzania-Diagnosis Mainly Based on Fasting Blood Glucose from Oral Glucose Tolerance Test

Gestational diabetes mellitus (GDM) is associated with poor pregnancy outcomes and increased long-term risk of metabolic diseases for both mother and child. In Tanzania, GDM prevalence increased from 0% in 1991 to 19.5% in 2016. Anaemia has been proposed to precipitate the pathogenesis of GDM. We aimed to examine the prevalence of GDM in a rural area of Tanzania with a high prevalence of anaemia and to examine a potential association between haemoglobin concentration and blood glucose during pregnancy. The participants were included in a population-based preconception, pregnancy and birth cohort study. In total, 538 women were followed during pregnancy and scheduled for an oral glucose tolerance test (OGTT) at week 32-34 of gestation. Gestational diabetes mellitus was diagnosed according to the WHO 2013 guidelines. Out of 392 women screened, 39% (95% CI: 34.2-44.1) had GDM, the majority of whom (94.1%) were diagnosed based solely on the fasting blood sample from the OGTT. No associations were observed between haemoglobin or ferritin and glucose measurements during pregnancy. A very high prevalence of GDM was found in rural Tanzania. In view of the laborious, costly and inconvenient OGTT, alternative methods such as fasting blood glucose should be considered when screening for GDM in low- and middle-income countries.

Risk factors for gestational diabetes: An umbrella review of meta-analyses of observational studies

BACKGROUND/OBJECTIVE

Gestational diabetes mellitus (GDM) is a common pregnancy complication, with complex disease mechanisms, and several risk factors may contribute to its onset. We performed an umbrella review to summarize the evidence from meta-analyses of observational studies on risk factors associated with GDM, evaluate whether there are indications of biases in this literature and identify which of the previously reported associations are supported by convincing evidence.

METHODS

We searched PubMed and ISI Web of Science from inception to December 2018 to identify meta-analyses examining associations between putative risk factors for GDM. For each meta-analysis we estimated the summary effect size, the 95% confidence interval, the 95% prediction interval, the between-study heterogeneity, evidence of small-study effects, and evidence of excess-significance bias.

RESULTS

Thirty eligible meta-analyses were identified, providing data on 61 associations. Fifty (82%) associations had nominally statistically significant findings (P<0.05), while only 15 (25%) were significant at P<10-6 under the random-effects model. Only four risk factors presented convincing evidence:, low vs. normal BMI (cohort studies), BMI ~30-35 kg/m2 vs. normal BMI, BMI >35 kg/m2 vs. normal BMI, and hypothyroidism.

CONCLUSIONS

The compilation of results from synthesis of observational studies suggests that increased BMI and hypothyroidism show the strongest consistent evidence for an association with GDM. Diet and lifestyle modifications in pregnancy should be tested in large randomized trials. Our findings suggest that women with known thyroid disease may be offered screening for GDM earlier in pregnancy.