Prophylactic Iron Supplementation in Pregnancy: A Controversial Issue

Oxidative Stress in Pregnancy

Recent years have seen an increased interest in the role of oxidative stress (OS) in pregnancy. Pregnancy inherently heightens susceptibility to OS, a condition fueled by a systemic inflammatory response that culminates in an elevated presence of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in the circulatory system. The amplified OS in pregnancy can trigger a series of detrimental outcomes such as underdevelopment, abnormal placental function, and a host of pregnancy complications, including pre-eclampsia, embryonic resorption, recurrent pregnancy loss, fetal developmental anomalies, intrauterine growth restriction, and, in extreme instances, fetal death. The body's response to mitigate the uncontrolled increase in RNS/ROS levels requires trace elements that take part in non-enzymatic and enzymatic defense processes, namely, copper (Cu), zinc (Zn), manganese (Mn), and selenium (Se). Determination of ROS concentrations poses a challenge due to their short half-lives, prompting the use of marker proteins, including malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), catalase (CAT), and glutathione (GSH). These markers, indicative of oxidative stress intensity, can offer indirect assessments of pregnancy complications. Given the limitations of conducting experimental studies on pregnant women, animal models serve as valuable substitutes for in-depth research. This review of such models delves into the mechanism of OS in pregnancy and underscores the pivotal role of OS markers in their evaluation.

Prevention and Management of Iron Deficiency/Iron-Deficiency Anemia in Women: An Asian Expert Consensus

The lack of standardized clinical practice impeding the optimal management of iron deficiency (ID) and iron deficiency anemia (IDA) in women is a global concern, particularly in the Asia-Pacific region. The aim of this study was to determine best practices through a Delphi consensus process. In Round 1, panelists were asked to rate their level of agreement with 99 statements across four domains: identification, diagnosis and assessment, prevention, and treatment of ID/IDA in women. In Round 2, panelists reappraised their ratings in view of the collective feedback and responses to Round 1. After two rounds, consensus (≥85% agreement) was reached for 84% of the Delphi statements. Experts agreed on the role of presenting symptoms and risk factors in prompting assessments of anemia and iron status in women. Experts repeatedly called for prevention, recommending preventive iron supplementation for pregnant women irrespective of anemia prevalence levels, and for non-pregnant adult women, adolescent girls, and perimenopausal women living in areas with a high prevalence of anemia. Experts unanimously agreed to prescribing oral ferrous iron as first-line therapy for uncomplicated ID/IDA. The recommendations and clinical pathway algorithms generated should be used to inform clinical practice and standardize the care of women at risk or presenting with ID/IDA in the Asia-Pacific region.

A Retrospective Study of Various Iron Preparations Oral Administration in Pregnant Women with Iron Deficiency Anemia

During pregnancy anemia is a common medical condition, with iron deficiency and megaloblastic anemia being the most common. The symptoms range from very mild to severe and if left without proper medical treatment, there can be serious consequences for both mother and fetus. The most frequent pregnancy problem is anemia. The term "Iron Deficiency Anemia" refers to erythropoiesis under conditions of absolute iron deficiency. This presupposes the depletion of iron stores in the body. Iron deficiency anemia or Sideropenic anemia is the most common form of anemia worldwide. Special attention must be given to nutrition during pregnancy. In the current retrospective study, it was evaluated the contribution of various iron preparations substitution during the pregnancy and puerperium.

Effectiveness of Dietary Interventions in Prevention and Treatment of Iron-Deficiency Anemia in Pregnant Women: A Systematic Review of Randomized Controlled Trials

Pregnant women are among the population groups most vulnerable to the development of anemia, as the overall iron requirement during pregnancy is significantly higher than in non-pregnant women. The aim of the systematic review was to assess the effectiveness of dietary interventions in the prevention and treatment of iron-deficiency anemia in pregnant women based on randomized-controlled trials. The systematic review was based on the PRISMA guidelines and is registered in the PROSPERO database (CRD42021261235). The search was conducted within PubMed and Web of Science databases for the period until June 2021. The included randomized controlled trials presented effectiveness of dietary interventions in prevention and treatment of iron-deficiency anemia in pregnant women. From the total number of 7825 screened records, the final number of seven studies were included in the systematic review. The procedure of screening, inclusion, reporting, and assessment of the risk of bias while using the revised Cochrane risk of bias tool for randomized trials was conducted by two independent researchers. The studies included in the systematic review were conducted in populations of anemic pregnant women, or mixed populations of anemic and non-anemic pregnant women. The interventions described within the studies were associated with including fortified products, regular products, or dietary counselling. They were based on providing an increased amount of iron, providing an increased amount of multiple nutrients, or general counselling only, while effectiveness was compared with effectiveness of the placebo, supplementation, or control group. The study duration was diversified from a few weeks to half a year or longer. The major biochemical measure assessed within the included studies was hemoglobin. All applied dietary interventions, based on providing increased amount of iron, providing increased amount of multiple nutrients, or general counselling only, were effective. The majority of included studies were assessed as ones of a medium risk of bias. For some studies a high risk of bias was indicated, which resulted from a risk of bias arising from the randomization process, due to deviations from the intended interventions, and in selection of the reported result. Considering this fact, more randomized controlled trials should be planned and conducted in a rigorous manner to confirm the formulated observations of effectiveness of the studied interventions based on providing an increased amount of iron, providing an increased amount of multiple nutrients, or general counselling only.

Iron supplementation during the first trimester of pregnancy after a national change of recommendation: a Danish cross-sectional study

In 2013, the Danish Health Authorities recommended a change in prophylactic iron supplementation to 40–50 mg/d from gestational week 10. Hence, the aims of the present study were (1) to estimate the prevalence of women who follow the Danish recommendation on iron supplementation during the last 3 weeks of the first trimester of pregnancy and (2) to identify potential sociodemographic, reproductive and health-related pre-pregnancy predictors for iron supplementation during the first trimester. We conducted a cross-sectional study with data from the hospital-based Copenhagen Pregnancy Cohort. Characteristics were analysed by descriptive statistics and multivariable logistic regression analysis was performed to examine the associations between predictors and iron supplementation during the last 3 weeks of the first trimester. The study population consisted of 23 533 pregnant women attending antenatal care at Copenhagen University Hospital - Rigshospitalet from October 2013 to May 2019. The prevalence of iron supplementation according to recommendations was 49⋅1 %. The pre-pregnancy factors of ≥40 years of age, the educational level below a higher degree and a vegetarian or vegan diet were identified as predictors for iron supplementation during the first trimester of pregnancy. Approximately half of the women were supplemented with the recommended dose of iron during the first trimester of pregnancy. We identified pre-pregnancy predictors associated with iron supplementation. Interventions that target women of reproductive age are needed. An enhanced focus on iron supplementation during pregnancy should be incorporated in pre-pregnancy and interpregnancy counselling.

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

OBJECTIVE

Gestational anaemia (GA) is common in developing countries. This study assessed the relationship of late GA and negative perinatal outcomes in participants recruited in a reference maternity unit of the Caribbean region of Colombia.

DESIGN

Prospective analytical birth cohort study. Maternal Hb and serum ferritin (SF) levels were measured. GA was defined as Hb levels <6·82 mmol/l (<11 g/dl), SF depletion as SF levels <12 µg/l. Birth outcomes such as low birth weight (LBW), preterm birth (PB) and small for gestational age (SGA) were examined.

SETTING

Mothers in the first stage of labour, living in urban or rural areas of Bolívar, were enrolled in an obstetrical centre located in Cartagena, Colombia. Blood and stool samples were taken prior delivery. Maternal blood count, SF levels and infant anthropometric data were recorded for analysis.

PARTICIPANTS

1218 pregnant women aged 18-42 years and their newborns.

RESULTS

Prevalence of GA and SF depletion was 41·6 % and 41·1 %, respectively. GA was positively associated with poverty-related sociodemographic conditions. Prenatal care attendance lowered the risk of PB, LBW and SGA. Birth weight was inversely associated with Hb levels, observing a -36·8 g decrease in newborn weight per 0·62 mmol/l (or 1 g/dl) of maternal Hb. SF depletion, but not anaemia, was associated with PB. SGA outcome showed a significant association with anaemia, but not a significant relationship with SF depletion.

CONCLUSIONS

Birth weight and other-related perinatal outcomes are negatively associated with Hb and SF depletion. Prenatal care attendance reduced the risk of negative birth outcomes.

Micronutrient supplementation in pregnancies following bariatric surgery: a practical review for clinicians

Patients who have undergone bariatric surgery are at high risk for nutritional deficiencies before and after surgery if no proper supplementation and close follow-up are maintained. As pregnancies after these surgeries are occurring more frequently, deficiencies imply risks for both mother and child. Nutritional needs for this specific population are different from that of patients with obesity or a non-bariatric population. This review provides a comprehensive summary of the most described vitamins and minerals during pregnancy, after bariatric surgery, and during pregnancy after bariatric surgery in order to summarize their specific needs and possible side effects and to provide a useful guideline to the involved caregivers.

Associations between Maternal Iron Supplementation in Pregnancy and Changes in Offspring Size at Birth Reflect Those of Multiple Micronutrient Supplementation

It was previously observed that in a population of a high-income country, dietary multiple micronutrient supplementation in pregnancy was associated with an increased risk of gestational diabetes (GDM) and increased offspring size at birth. In this follow-up study, we investigated whether similar changes are observed with dietary iron supplementation. For this we used the prospective Cambridge Baby Growth Study with records of maternal GDM status, nutrient supplementation, and extensive offspring birth size measurements. Maternal iron supplementation in pregnancy was associated with GDM development (risk ratio 1.67 (1.01-2.77), p = 0.048, n = 677) as well as offspring size and adiposity (n = 844-868) at birth in terms of weight (β' = 0.078 (0.024-0.133); p = 0.005), head circumference (β' = 0.060 (0.012-0.107); p = 0.02), body mass index (β' = 0.067 (0.014-0.119); p = 0.01), and various skinfold thicknesses (β' = 0.067-0.094; p = 0.03-0.003). In a subset of participants for whom GDM statuses were available, all these associations were attenuated by adjusting for GDM. Iron supplementation also attenuated the associations between multiple micronutrient supplementation and these same measures. These results suggest that iron supplementation may mediate the effects associated with multiple micronutrient supplementation in pregnancy in a high-income country, possibly through the increased risk of developing GDM.

Maternal iron-deficiency is associated with premature birth and higher birth weight despite routine antenatal iron supplementation in an urban South African setting: The NuPED prospective study

Background

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.

Methods

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.

Results

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.

Conclusion

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.

Blood Products in the Management of Abnormal Placentation

A critical tool in the successful management of patients with abnormal placentation is an established massive transfusion protocol designed to rapidly deliver blood products in obstetrical and surgical hemorrhage. Spurred by trauma research and an understanding of consumptive coagulopathy, the past 2 decades have seen a shift in volume resuscitation from an empiric, crystalloid-based method to balanced, targeted transfusion therapy. The present article reviews patient blood management in abnormal placentation, beginning with optimizing the patient's status in the antenatal period to the laboratory assessment and transfusion strategy for blood products at the time of hemorrhage.

Pathophysiology of iron overload-induced renal injury and dysfunction: Roles of renal oxidative stress and systemic inflammatory mediators

Iron-overload has been recognized as a risk factor for organ dysfunction and damage resulting in diseases such as liver and heart disease, diabetes mellitus, and neurodegenerative diseases. This study investigated renal function and some systemic inflammatory indices in iron-overloaded male Wistar rats. Thirty animals were equally distributed into 3groups and treated daily i.p. with either normal saline (0.2 ml; control), iron (as ferrous sulphate) (15 mg/kg) or iron (30 mg/kg) for 21days respectively. Post-treatment, blood samples were obtained from each animal by cardiac puncture after light anaesthesia into plain sample bottles. Iron, ferritin, transferrin, creatinine, urea, albumin, total protein, interleukin-6 (IL-6), prostaglandins-E2 and tumor necrosis factor-α (TNF-α) were analysed in serum. Kidney homogenates were obtained per group and analysed for superoxide dismutase (SOD), total antioxidant capacity (TAC), reduced glutathione (GSH), lipid peroxidation (MDA) and nitric oxide (NO). Kidney histology was evaluated per group using both Haematoxylin and Eosin and periodic acid Schiff stains. Iron-overload caused a graded increase (p < 0.05) in serum iron, ferritin, transferrin, creatinine, urea, IL-6, TNF-α, TAC, MDA and NO levels as well as a reduction in albumin levels, renal SOD and GSH in groups 2 (iron 15 mg/kg) and 3 (iron 30 mg/kg) respectively compared to control. Histological evaluation of the kidney showed structural and tubular aberrations consistent with renal damage via inflammatory processes in iron overloaded rats. Our present study suggests that iron-overloading causes renal dysfunction by triggering the evolution of several inflammatory mediators which lead to a cascade of systemic and renal inflammatory processes that alter renal structure and function.

Impact and management of iron deficiency and iron deficiency anemia in women's health

INTRODUCTION

Iron deficiency and iron deficiency anemia are highly prevalent among women throughout their lives. Some females are particularly vulnerable to iron deficiency/iron deficiency anemia, including those with heavy menstrual bleeding (HMB) and pregnant/postpartum women. Despite the high prevalence of iron deficiency/iron deficiency anemia in women, the condition is still underdiagnosed and therefore undertreated, with serious clinical consequences. Areas covered: The following review examines the impact of iron deficiency and iron deficiency anemia on clinical outcomes and quality of life in women from adolescence to post-menopause, paying particular attention to guidelines and current recommendations for diagnostic tests and management. Expert commentary: There are numerous adverse health consequences of an iron-deficient state, affecting all aspects of the physical and emotional health and well-being of women. Guidelines must be developed to help clinicians better identify and treat women at risk of iron deficiency or iron deficiency anemia, particularly those with HMB, or who are pregnant or postpartum. Replacement therapy with oral or intravenous iron preparations is the mainstay of treatment for iron deficiency/iron deficiency anemia, with red blood cell transfusion reserved for emergency situations. Each iron therapy type is associated with benefits and limitations which impact their use.

Effects of micronutrients on placental function: evidence from clinical studies to animal models

Micronutrient deficiencies are common in pregnant women due to low dietary intake and increased requirements for fetal development. Low maternal micronutrient status is associated with a range of pregnancy pathologies involving placental dysfunction, including fetal growth restriction (FGR), small-for-gestational age (SGA), pre-eclampsia and preterm birth. However, clinical trials commonly fail to convincingly demonstrate beneficial effects of supplementation of individual micronutrients, attributed to heterogeneity and insufficient power, potential interactions and lack of mechanistic knowledge of effects on the placenta. We aimed to provide current evidence of relationships between selected micronutrients (vitamin D, vitamin A, iron, folate, vitamin B12) and adverse pregnancy outcomes, combined with understanding of actions on the placenta. Following a systematic literature search, we reviewed data from clinical, in vitro and in vivo studies of micronutrient deficiency and supplementation. Key findings are potential effects of micronutrient deficiencies on placental development and function, leading to impaired fetal growth. Studies in human trophoblast cells and rodent models provide insights into underpinning mechanisms. Interestingly, there is emerging evidence that deficiencies in all micronutrients examined induce a pro-inflammatory state in the placenta, drawing parallels with the inflammation detected in FGR, pre-eclampsia, stillbirth and preterm birth. Beneficial effects of supplementation are apparent in vitro and in animal models and for combined micronutrients in clinical studies. However, greater understanding of the roles of these micronutrients, and insight into their involvement in placental dysfunction, combined with more robust clinical studies, is needed to fully ascertain the potential benefits of supplementation in pregnancy.

Maternal Anemia and Low Birth Weight: A Systematic Review and Meta-Analysis

Objective: To systematically analyze the relationship between maternal anemia and low birth weight. Methods: A search of studies was conducted in the main databases (Medline, Embase, Scopus, Web of Science, SciELO, and Lilacs), the gray literature, and the reference lists of selected articles. Cohort and case-control studies that met the eligibility criteria were included in the review. There was no limitation on the language or date of publication. Article selection and data extraction were performed by two independent reviewers. Meta-analyses with random effects, subgroup analyses and meta-regressions were performed. Publication bias was measured using Egger regression and visual funnel plot inspection. Results: A total of 7243 articles were found, of which 71 comprised the systematic review and 68 were included in the meta-analyses. Maternal anemia was associated with low birth weight with an adjusted OR: 1.23 (95% CI: 1.06–1.43) and I²: 58%. The meta-regressions confirmed that the sample size and the methodological quality may partially explain the statistical heterogeneity. Conclusions: Maternal anemia was considered a risk factor for low birth weight.

Maternal Anemia and Low Birth Weight: A Systematic Review and Meta-Analysis

OBJECTIVE

To systematically analyze the relationship between maternal anemia and low birth weight.

METHODS

A search of studies was conducted in the main databases (Medline, Embase, Scopus, Web of Science, SciELO, and Lilacs), the gray literature, and the reference lists of selected articles. Cohort and case-control studies that met the eligibility criteria were included in the review. There was no limitation on the language or date of publication. Article selection and data extraction were performed by two independent reviewers. Meta-analyses with random effects, subgroup analyses and meta-regressions were performed. Publication bias was measured using Egger regression and visual funnel plot inspection.

RESULTS

A total of 7243 articles were found, of which 71 comprised the systematic review and 68 were included in the meta-analyses. Maternal anemia was associated with low birth weight with an adjusted OR: 1.23 (95% CI: 1.06⁻1.43) and I²: 58%. The meta-regressions confirmed that the sample size and the methodological quality may partially explain the statistical heterogeneity.

CONCLUSIONS

Maternal anemia was considered a risk factor for low birth weight.