Effects of iron supplementation on maternal hematologic status in pregnancy

OBJECTIVES: Prenatal iron supplementation has been the standard recommendation for reducing maternal anemia in developing countries for the past 30 years. This article reviews the efficacy of iron supplementation on hemoglobin levels in pregnant women in developing countries. METHODS: Data from randomized controlled trials published between 1966 and 1998 were pooled. Meta-analyses of the relative change in maternal hemoglobin associated with iron supplementation were stratified by initial hemoglobin levels, duration of supplementation, and daily gestational supplement dose and supplementation with other nutrients. RESULTS: Iron supplementation raises hemoglobin levels. Its effects are dose dependent and are related to initial hematologic status. The extent to which iron supplementation can reduce maternal anemia is unclear. CONCLUSIONS: The extent to which maternal hemoglobin levels can be increased by recommended prenatal supplementation is limited and has uncertain physiological benefits. Other approaches, including food fortification and prevention and treatment of other causes of anemia, require methodologically rigorous evaluation to find effective answers to this global problem.     

Is There a Causal Relationship between Iron Deficiency or Iron-Deficiency Anemia and Weight at Birth, Length of Gestation and Perinatal Mortality?

An extensive literature review was conducted to identify whether iron deficiency, iron-deficiency anemia and anemia from any cause are causally related to low birth weight, preterm birth or perinatal mortality. Strong evidence exists for an association between maternal hemoglobin concentration and birth weight as well as between maternal hemoglobin concentration and preterm birth. It was not possible to determine how much of this association is attributable to iron-deficiency anemia in particular. Minimal values for both low birth weight and preterm birth occurred at maternal hemoglobin concentrations below the current cut-off value for anemia during pregnancy (110 g/L) in a number of studies, particularly those in which maternal hemoglobin values were not controlled for the duration of gestation. Supplementation of anemic or nonanemic pregnant women with iron, folic acid or both does not appear to increase either birth weight or the duration of gestation. However, these studies must be interpreted cautiously because most are subject to a bias toward false-negative findings. Thus, although there may be other reasons to offer women supplemental iron during pregnancy, the currently available evidence from studies with designs appropriate to establish a causal relationship is insufficient to support or reject this practice for the specific purposes of raising birth weight or lowering the rate of preterm birth.     

Pregnancy and Iron Deficiency: Unresolved Issues

Iron deficiency and iron deficiency anemia are prevalent among pregnant women. The extent to which iron deficiency affects maternal and neonatal health is uncertain. Existing data suggest that maternal iron deficiency anemia may be associated with adverse outcomes, including preterm delivery and higher maternal mortality. Further research is needed on the maternal and neonatal benefits of iron supplementation during pregnancy.     

Malaria in pregnancy: current issues

Though not known why, pregnant women are far more susceptible to Plasmodium falciparum malaria during their first pregnancies. Therefore, in sub-Saharan African countries endemic for malaria, almost half of all primigravidae will be parasitemic at their first antenatal visit. Some estimate that up to half of all low birth weight babies born to primigravidae in malaria-endemic areas may be attributable to malaria. Intrauterine growth in the context of maternal parasitemia therefore has major adverse implications for child survival. For the mothers, the prevalence of anemia among pregnant women is greatly increased in malarious areas, and iron-deficiency anemia in pregnant women in developed countries has been associated with pre-term birth and low birth weight. These adverse health and developmental consequences of malaria infection among mothers and their babies is compounded by the absence of any widely-applied recommendation for malaria control in pregnant women in Africa. Current control strategies are nonetheless described. The influence of HIV infection in relation to the effectiveness of malaria drug control during pregnancy has not been assessed.     

A national survey of iron and folate status in pregnant women in Switzerland.

Women often do not meet the increased iron and folate needs of pregnancy. Maternal iron-deficiency anemia is associated with poor maternal and infant outcomes, including preterm delivery and low birth weight. Poor folate status increases risk for maternal anemia, spontaneous abortion, and congenital defects. Because of this, supplemental iron and folate are often recommended during pregnancy. There are few data on iron and folate status in pregnant women in Switzerland. We measured iron and folate status in a national sample of Swiss pregnant women, estimated the prevalence of anemia, and determined if supplement use is associated with iron and/or folate status in this group. A 3-stage probability to size cluster sampling method was used to obtain a representative national sample of pregnant women (n = 381) in the second and third trimester. We measured hemoglobin, hematocrit, mean corpuscular volume, and serum folate and ferritin concentrations. Serum transferrin receptor concentration was determined in anemic subjects. The use of iron and folate supplements was evaluated by questionnaire. Mean hemoglobin (+/- SD) in the sample was 123 g/L (+/- 1.0). The prevalence of anemia was 6%. Of the 21 anemic women, 11 were iron-deficient, giving an iron-deficiency anemia prevalence of 3%. Nineteen percent of women had low serum ferritin concentrations (< 12 micrograms/L) and 4% had low serum folate concentration (< 2.5 micrograms/L). Supplements containing iron were taken by 65% of women, and 63% were taking folate-containing supplements. Women in the second and third trimester taking folate-containing supplements had significantly higher serum folate concentrations compared to those not taking a folate supplement (p < 0.001). In the third trimester, women taking iron-containing supplements had significantly higher serum ferritin concentrations compared to those not taking an iron-containing supplement (p < 0.01). Our findings indicate that iron and folate status appears to be adequate in the majority of pregnant women in Switzerland, and that use of iron and folate supplements may have a positive impact on status.     

Biological mechanisms that might underlie iron's effects on fetal growth and preterm birth

A negative association between anemia and duration of gestation and low birth weight has been reported in the majority of studies, although a causal link remains to be proven. This paper explores potential biological mechanisms that might explain how anemia, iron deficiency or both could cause low birth weight and preterm delivery. The risk factors for preterm delivery and intrauterine growth retardation are quite similar, although relatively little is understood about the influence of maternal nutritional status on risk of preterm delivery. Several potential biological mechanisms were identified through which anemia or iron deficiency could affect pregnancy outcome. Anemia (by causing hypoxia) and iron deficiency (by increasing serum norepinephrine concentrations) can induce maternal and fetal stress, which stimulates the synthesis of corticotropin-releasing hormone (CRH). Elevated CRH concentrations are a major risk factor for preterm labor, pregnancy-induced hypertension and eclampsia, and premature rupture of the membranes. CRH also increases fetal cortisol production, and cortisol may inhibit longitudinal growth of the fetus. An alternative mechanism could be that iron deficiency increases oxidative damage to erythrocytes and the fetoplacental unit. Iron deficiency may also increase the risk of maternal infections, which can stimulate the production of CRH and are a major risk factor for preterm delivery. It would be useful to explore these potential biological mechanisms in randomized, controlled iron supplementation trials in anemic and iron-deficient pregnant women.     

A free weekly iron-folic acid supplementation and regular deworming program is associated with improved hemoglobin and iron status indicators in Vietnamese women

Background  

Anemia due to iron deficiency is recognized as one of the major nutritional deficiencies in women and children in developing countries. Daily iron supplementation for pregnant women is recommended in many countries although there are few reports of these programs working efficiently or effectively. Weekly iron-folic acid supplementation (WIFS) and regular deworming treatment is recommended for non-pregnant women living in areas with high rates of anemia. Following a baseline survey to assess the prevalence of anemia, iron deficiency and soil transmitted helminth infections, we implemented a program to make WIFS and regular deworming treatment freely and universally available for all women of reproductive age in two districts of a province in northern Vietnam over a 12 month period. The impact of the program at the population level was assessed in terms of: i) change in mean hemoglobin and iron status indicators, and ii) change in the prevalence of anemia, iron deficiency and hookworm infections.     

中国妊娠期贫血流行状况分析

目的 了解中国妊娠期贫血流行状况,为完善中国妊娠期贫血防控政策、推进中国妊娠期贫血防控工作提供科学依据.方法 2019年11—12月在万方、知网、Sinomed、Pubmed等数据库采用关键词组配方式检索关于中国妊娠期贫血流行情况的文献.采用NoteExpress、Excel软件对相关文献进行数据管理和分析.结果 共纳...     

Safe motherhood: an insight into maternal mortality in the developing world

It is a tragic fact that in the very act of giving birth, of achieving motherhood, nearly half a million women die every year worldwide. This article presents an insight into maternal mortality in developing countries. Evidence shows that women who escape death survive with serious ill health and a host of pregnancy- and childbirth-related complications. Unfortunately, women from developing countries face the gravest risks. These women die of neglect and ignorance and inaccessibility to required health services. In view of the above, the UN International Children's Emergency Fund and the WHO, in collaboration with many countries, took the initiative in bringing down the infant mortality rate around the world, more significantly in the developing world. Also, the WHO reported 585,000 maternal deaths worldwide in 1990, only 4000 of which occurred in developed countries. Causes of these deaths are deeply rooted within the socioeconomic milieu in which people live. Therefore, this problem calls for a long-term strategy.     

孕产妇贫血患病率及影响因素分析

目的:调查我区孕产妇缺铁性贫血患病率及影响因素,提出干预措施。方法:采用分层整群抽样方法,对银川市等10个市、县(区)的孕产妇监测血红蛋白,并对有关因素进行专人问卷调查。结果:全区孕产妇缺铁性贫血平均患病率为20.27%。孕周、产后周数、年龄、孕产妇及其丈夫文化程度、民族、家庭年人均收入、膳食习惯、是否了解贫血防治知识、孕期患病、分娩地点与孕产妇贫血患病率有关。结论:孕产期妇女贫血发生率较高,应引起高度重视,并应针对影响贫血发生的主要因素进行干预,减少贫血的发生率,对降低孕妇和围产儿死亡率有重要意义。     

Iron status and its association with pregnancy outcome in Korean pregnant women

OBJECTIVE: The purpose of this study was to assess the prevalence of iron deficiency anemia among Korean pregnant women and to assess the association between maternal hemoglobin (Hb) level and pregnancy outcome. DESIGN: A longitudinal study. SETTING: Ewha Womans University Hospital, Seoul, Korea. SUBJECTS: A total of 248 normal pregnant women of 24-28 weeks gestation and 190 babies born to the pregnant subjects. METHODS: Maternal anthropometry, blood parameters and pregnancy outcomes were measured. RESULTS: Mean Hb, serum iron concentration, transferrin saturation and total iron binding capacity of the subjects were 11.4 g/dl, 89.4 microg/dl, 18.7% and 484.6 microg/dl, respectively, and 30.2% of the subjects were anemic judged by Hb concentration of <10.5 g/dl. When subjects were classified into tertile groups based on Hb levels, the lowest tertile (HbT1) group had significantly lower concentrations of cord serum iron and albumin than those in the highest tertile (HbT3) group. Newborn infants from the HbT1 group had significantly higher rates of preterm delivery, low birth weight and low Apgar scores than those in other groups. Logistic regression analysis showed that maternal serum albumin and Hb level were the most important predictive variables for low birth weight.Conclusions:A substantial proportion of Korean pregnant women were at risk of anemia. Infants born to women with a low Hb level showed a lower birth weight, height and Apgar scores.     

Impact of nutritional deficiencies on anemia in pregnant women

Dietary deficiency in iron and to a lesser extent folic acid is the principle cause of anemia in the world. Reproductive aged women and growing children are the principle groups at risk of anemia. About half of nonpregnant reproductive aged women in tropical countries have hemoglobin levels lower than 12 g/100 ml, the level used by the World Health Organization to define anemia. Nutritional anemia is even more widespread among pregnant and lactating women because of the increased needs for iron during those periods. Pregnant women need almost 500 mg of iron for their increased red blood cell mass, 220 mg for routine iron loss through the urine, bile, sweat, and other routes; 290 mg for the fetus, and almost 25 mg for the placenta. In all, the pregnant women theoretically requires over 1000 mg of iron through diet or bodily reserves. Healthy, well-nourished women have total iron reserves of 2500 mg, but according to published data almost 2/3 of pregnant women even in favorable circumstances end their pregnancies with no remaining iron reserves. In tropical regions the lack of iron reserves is aggravated by parasites and infections, closely spaced pregnancies that do not allow restoration of reserves, and poor dietary availability of iron. Anemia during pregnancy is associated with elevated risks of maternal morbidity and mortality. Fatigue, dyspnea, palpitations and tachycardia, vertigo, loss of appetite and cravings for soil or other inappropriate substances are frequently observed in anemic women. The risks of prematurity and low weight are increased for infants of anemic women. Fetal malformation may be associated with folic acid deficiency. Nutrition education is needed for pregnant women. Local foods may be enriched with iron, and pregnant women may be given iron and vitamin B12 supplements directly. Iron supplements may rapidly increase iron reserves, but they are poorly tolerated by many women. The supplements should be avoided if possible early in the pregnancy because digestive intolerance is more likely in the 1st months of pregnancy. Parasitic and bacterial infections should be diagnosed and treated as a step in controlling anemia.     

Low birth weight in the United States

Pregnancy outcomes in the United States and other developed countries are considerably better than those in many developing countries. However, adverse pregnancy outcomes are generally more common in the United States than in other developed countries. Low-birth-weight infants, born after a preterm birth or secondary to intrauterine growth restriction, account for much of the increased morbidity, mortality, and cost. Wide disparities exist in both preterm birth and growth restriction among different population groups. Poor and black women, for example, have twice the preterm birth rate and higher rates of growth restriction than do most other women. Low birth weight in general is thought to place the infant at greater risk of later adult chronic medical conditions, such as diabetes, hypertension, and heart disease. Of interest, maternal thinness is a strong predictor of both preterm birth and fetal growth restriction. However, in the United States, several nutritional interventions, including high-protein diets, caloric supplementation, calcium and iron supplementation, and various other vitamin and mineral supplementations, have not generally reduced preterm birth or growth restriction. Bacterial intrauterine infections play an important role in the etiology of the earliest preterm births, but, at least to date, antibiotic treatment either before labor for risk factors such as bacterial vaginosis or during preterm labor have not consistently reduced the preterm birth rate. Most interventions have failed to reduce preterm birth or growth restriction. The substantial improvement in newborn survival in the United States over the past several decades is mostly due to better access to improved neonatal care for low-birth-weight infants.     

Safe Motherhood Initiative: the art of the feasible]

In 1987 the worldwide health program, the Safe Motherhood Initiative, was launched in Nairobi by international organizations to combat the alarming rate of maternal mortality resulting from pregnancy and delivery complications that takes 500,000 lives a year, 98% of them in developing countries. Yet the rate has scarcely diminished since ten. In underdeveloped countries maternal mortality is around 400 per 100,000 live births compared to 10-20 in Europe. The rate is the highest in high fertility regions such as Africa and Southeast Asia. The causes are blood loss, infection, hypertensive episodes during pregnancy, rupture of the uterus, and sepsis from botched induced abortion. In postpartum hemorrhage, especially in grand multiparous women, blood transfusion can be lifesaving. However, in a large part of Africa blood is often unusable because of infection with AIDS. In Jamaica and Bangladesh family planning campaigns particularly aimed at adolescents have yielded good results. In Zimbabwe campaigns target mostly men because of their authority. The utility of basic training of traditional birth attendants (TBAs) in delivery is highly questionable, and more thorough going training is being evaluated. Obstacles to reduction of maternal mortality within the Safe Motherhood program include shortage of funds, lack of coordination with local entities, inadequate antenatal care, illiteracy, and cultural barriers. Communication and training activities are essential, as demonstrated by the Matlab project in Bangladesh. The Matlab region had 200,000 people, 83% of women were illiterate, and maternal mortality reached 400 per 100,000 live births. 3 years after schooled midwives trained TBAs and integrated care for pregnant women, and transportation by boat to a newly built clinic was arranged, the maternal mortality rate declined to 140 from 380 per 100,000 live births in the intervention area (p = 0.02) compared to the control region. In the coming year the halving of maternal mortality is envisioned through prevention of anemia, tetanus, and extensive contraceptive use.     

Prevalence of micronutrient deficiency particularly of iron, zinc and folic acid in pregnant women in South East Asia

Micronutrient deficiency, whether clinical or subclinical, may affect growth, cognition and reproductive performance. In pregnant women moderate to severe deficiencies of iron, zinc and folic acid have been shown to increase risk of low birth weight, pregnancy complications and birth defects. Any attempt to introduce a micronutrient supplementation programme during pregnancy must be based on adequate data on the prevalence of micronutrient deficiencies, their adverse effects and the potential for reversing these through supplementation. This paper reviews parameters for assessment of iron, zinc and folic acid deficiencies in pregnancy and the available data on prevalence of these in pregnant women in South Asia. Iron deficiency and anemia affect 50 % or more of pregnant women, the prevalence of folic acid deficiency may be up to 30-50 % and there is evidence to suggest that zinc deficiency is likely to be widespread but supportive data are scarce.     

Micronutrients and reproductive health issues: an international perspective

Micronutrients may have a role in enhancing reproductive health of women living in the developing world. Two illustrative micronutrients, zinc and vitamin A, have received some attention in this regard. Numerous animal experiments and observational studies suggest the potential role of zinc deficiency in labor and delivery-related complications such as premature rupture of membrane, placental abruption, preterm labor and inefficient uterine contraction. These associations have not been confirmed in supplementation studies. Zinc does not appear to be a limiting factor in intrauterine growth in the developing world, contrary to some evidence of its suggested benefit among women residing in industrialized countries. One study in Nepal found that maternal vitamin A or beta-carotene supplementation reduces pregnancy-related mortality but not infant mortality. These findings are corroborated by observations of the significantly higher risk of mortality among night-blind women compared to non-night-blind women long after the termination of pregnancy and the resolution of night blindness. Maternal multiple micronutrient supplementation needs more careful evaluation before its use in large-scale programs. Two recent trials indicated that a prenatal multiple micronutrient supplement provides no added advantage over iron and folate in reducing outcomes such as low birth weight and probably no survival benefit. Data are also suggestive that adding zinc may negate the beneficial effect of iron and folic acid on birth weight. Research is needed to further our understanding of nutrient-nutrient interactions.     

Iron in the diets of rural Honduran women and children

Iron deficiency, a major cause of nutritional anemia, is the most prevalent micronutrient deficiency in the world. One of the main causes of iron deficiency anemia in developing countries is poor availability of absorbable iron from the diet. This study investigates the level of iron intake, bio‐availability, and adequacy in the diets of women and children in the rural west of Honduras. We find that the dietary iron status of this population is very poor. Fifty‐seven percent of the children under one year of age and 23% of 1 to 2 year olds are likely to have inadequate intakes to prevent iron deficiency anemia. Almost all of the pregnant women and 33% of the non‐pregnant non‐lactating women are at risk of developing iron deficiency anemia. The corn based Honduran diet, owing to high phytate levels, has a low bio‐availabiiity for iron. Extremely low intakes of fruits and vegetables and of meats, coupled with significant intake of coffee by all age groups, further limits the availability of dietary iron in the Honduran population.     

Pregnancy in the Sickle Cell Disease and Fetomaternal Outcomes in Different Sickle cell Genotypes: A Systematic Review and Meta-Analysis

BackgroundPregnancy is a major concern among women with the sickle cell disease (SCD), and it is associated with increased adverse outcomes. The aim of the present meta-analysis is to report the fetomaternal outcomes in different sickle cell genotypes.MethodsIn this systematic review and meta-analysis, a comprehensive search of databases and search engines such as PubMed, Scopus, Web of Science, ProQuest, Cochrane Library, Science Direct and Google Scholar were performed. Any observational studies that had compared at least one outcome such as maternal outcomes, fetal outcomes, and morbidity between two groups of pregnant women with different types of sickle cell genotypes and pregnant women without SCD were evaluated.ResultsA total number of 9,827 pregnant women with SCD were examined. The results showed that pregnancy in SCD increased the risk of adverse outcomes for the mothers (including postpartum hemorrhage, prematurity, pregnancy-induced hypertension, pre-eclampsia, eclampsia, cesarean section, lower segment cesareansection, maternal death), fetus (including live births, low birth weight, intrauterine growth restriction, APGAR score at 5 min <7, stillbirth, neonatal death, perinatal mortality, acute fetal distress, intrauterine fetal death) and morbidity among the SCD(severe anemia, urinary tract infection, blood transfusion, painful crisis, acute chest syndrome, vaso-occlusive crises).ConclusionAccording to the results of this meta-analysis, pregnancy in the SCD is associated with an increased risk of maternal outcomes, fetal outcomes, and morbidity among SCD patients with different genotypes. Pregnancy in sickle cell hemoglobinopathies needs careful multidisciplinary management and cautious caring so as to decrease maternal and fetal morbidity and mortality.     

Mediational pathways connecting secondary education and age at marriage to maternal mortality: A comparison between developing and developed countries

While studies have shown that maternal mortality rates have been improving worldwide, rates are still high across developing nations. In general, poor health of women is associated with higher maternal mortality rates in developing countries. Understanding country-level risk factors can inform intervention and prevention efforts that could bring high maternal mortality rates down. Specifically, the authors were interested in investigating whether: (1) secondary education participation (SEP) or age at marriage (AM) of women were related to maternal mortality rates, and (2) adolescent birth rate and contraceptive use (CU) acted as mediators of this association. The authors add to the literature with this current article by showing the relation of SEP and AM to maternal mortality rates globally (both directly and indirectly through mediators) and then by comparing differences between developed and developing/least developed countries. Path analysis was used to test the hypothesized model using country level longitudinal data from 2000 to 2010 obtained from United Nations publications, World Health Organization materials, and World Bank development reports. Findings include a significant correlation between SEP and AM for developing countries; for developed countries the relation was not significant. As well, SEP in developing countries was associated with increased CU. Women in developing countries who finish school before marriage may have important social capital gains.     

Epidemiology and control of gonococcal ophthalmia neonatorum

From a public health point of view gonococcal ophthalmia neonatorum (GCON) is important as it can rapidly lead to blindness. The frequency of GCON is determined by the prevalence of maternal gonococcal infection. In most industrialized countries the prevalence of gonorrhoea in pregnant women is less than 1%; in developing countries the rates are between 3% and 15%, more than 50% being due to penicillinase-producing Neisseria gonorrhoeae strains (PPNG). The rate of transmission from mother to newborn is between 30% and 50%. Strategies for the control of GCON include: (1) prevention of gonococcal infection in women of childbearing age, (2) detection and treatment of gonococcal infection in pregnant women, (3) eye prophylaxis in the newborn at birth, and (4) diagnosis and treatment of GCON. Eye prophylaxis by the instillation immediately after birth of either 1% silver nitrate eye drops or 1% tetracycline eye ointment is very effective. This reduces the GCON incidence by 80% to 95% and is highly cost-effective, particularly in high-risk settings.