Monitoring oral iron therapy with protoporphyrin/heme ratios in pregnant women

Comparison of different doses of daily iron supplementation for anemia prophylaxis in pregnancy: A systematic review

Different doses of iron are used for oral supplementation during pregnancy throughout the world. This objective of this review is to describe the effectiveness and side effect profile of different doses of oral iron supplementation for prophylaxis of anemia among pregnant women. Published literature was searched using keywords "iron," "pregnancy," and "supplementation" and related terms. Gray literature was searched in medical libraries including National Medical Library, Dr. B. B. Dikshit library, and library of ICMR. Intervention studies comparing different doses of oral iron given as prophylaxis for anemia during pregnancy, published till December 2017, were retrieved. Studies done only among anemic patients, and studies comparing oral iron with placebo were excluded. In total, 1588 studies were obtained and 11 of them met the objectives. In global studies, prophylactic dose of 30 mg and above is shown to maintain normal hemoglobin. Among the studies from India, prophylactic dose of 120 mg showed consistent results and 60 mg showed inconsistent results in increasing both hemoglobin and ferritin levels. No significant difference in side effects was reported up to 80 mg iron in global studies and the side effects were comparable with 60 to 240 mg doses in Indian studies. It was evident from the review that a state of clinical equipoise exists for the ideal dose of iron supplementation for the prevention of anemia in pregnancy in terms of efficacy and side effect profile. Robust clinical trial as well as technical consultation is required, especially in Indian setting to explore this question further.

Intermittent oral iron supplementation during pregnancy

BACKGROUND

Anaemia is a frequent condition during pregnancy, particularly among women in low- and middle-income countries. Traditionally, gestational anaemia has been prevented with daily iron supplements throughout pregnancy, but adherence to this regimen due to side effects, interrupted supply of the supplements, and concerns about safety among women with an adequate iron intake, have limited the use of this intervention. Intermittent (i.e. two or three times a week on non-consecutive days) supplementation has been proposed as an alternative to daily supplementation.

OBJECTIVES

To assess the benefits and harms of intermittent supplementation with iron alone or in combination with folic acid or other vitamins and minerals to pregnant women on neonatal and pregnancy outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 July 2015), the WHO International Clinical Trials Registry Platform (ICTRP) (31 July 2015) and contacted relevant organisations for the identification of ongoing and unpublished studies (31 July 2015).

SELECTION CRITERIA

Randomised or quasi-randomised trials.

DATA COLLECTION AND ANALYSIS

We assessed the methodological quality of trials using standard Cochrane criteria. Two review authors independently assessed trial eligibility, extracted data and conducted checks for accuracy.

MAIN RESULTS

This review includes 27 trials from 15 countries, but only 21 trials (with 5490 women) contributed data to the review. All studies compared daily versus intermittent iron supplementation. The methodological quality of included studies was mixed and most had high levels of attrition.The overall assessment of the quality of the evidence for primary infant outcomes was low and for maternal outcomes very low.Of the 21 trials contributing data, three studies provided intermittent iron alone, 14 intermittent iron + folic acid and four intermittent iron plus multiple vitamins and minerals in comparison with the same composition of supplements provided in a daily regimen.Overall, for women receiving any intermittent iron regimen (with or without other vitamins and minerals) compared with a daily regimen there was no clear evidence of differences between groups for any infant primary outcomes: low birthweight (average risk ratio (RR) 0.82; 95% confidence interval (CI) 0.55 to 1.22; participants = 1898; studies = eight; low quality evidence), infant birthweight (mean difference (MD) 5.13 g; 95% CI -29.46 to 39.72; participants = 1939; studies = nine; low quality evidence), premature birth (average RR 1.03; 95% CI 0.76 to 1.39; participants = 1177; studies = five; low quality evidence), or neonatal death (average RR 0.49; 95% CI 0.04 to 5.42; participants = 795; studies = one; very low quality). None of the studies reported congenital anomalies.For maternal outcomes, there was no clear evidence of differences between groups for anaemia at term (average RR 1.22; 95% CI 0.84 to 1.80; participants = 676; studies = four; I² = 10%; very low quality). Women receiving intermittent supplementation had fewer side effects (average RR 0.56; 95% CI 0.37 to 0.84; participants = 1777; studies = 11; I² = 87%; very low quality) and were at lower risk of having high haemoglobin (Hb) concentrations (greater than 130 g/L) during the second or third trimester of pregnancy (average RR 0.53; 95% CI 0.38 to 0.74; participants = 2616; studies = 15; I² = 52%; (this was not a primary outcome)) compared with women receiving daily supplements. There were no significant differences in iron-deficiency anaemia at term between women receiving intermittent or daily iron + folic acid supplementation (average RR 0.71; 95% CI 0.08 to 6.63; participants = 156; studies = one). There were no maternal deaths (six studies) or women with severe anaemia in pregnancy (six studies). None of the studies reported on iron deficiency at term or infections during pregnancy.Most of the studies included in the review (14/21 contributing data) compared intermittent oral iron + folic acid supplementation compared with daily oral iron + folic acid supplementation (4653 women) and findings for this comparison broadly reflect findings for the main comparison (any intermittent versus any daily regimen).Three studies with 464 women examined supplementation with intermittent oral iron alone compared with daily oral iron alone. There were no clear differences between groups for mean birthweight, preterm birth, maternal anaemia or maternal side effects. Other primary outcomes were not reported.Four studies with a combined sample size of 412 women compared intermittent oral iron + vitamins and minerals supplementation with daily oral iron + vitamins and minerals supplementation. Results were not reported for any of the review's infant primary outcomes. One study reported fewer maternal side effects in the intermittent iron group, and two studies that more women were anaemic at term compared with those receiving daily supplementation.Where sufficient data were available for primary outcomes, we set up subgroups to look for possible differences between studies in terms of earlier or later supplementation; women's anaemia status at the start of supplementation; higher and lower weekly doses of iron; and the malarial status of the region in which the trials were conducted. There was no clear effect of these variables on results.

AUTHORS' CONCLUSIONS

This review is the most comprehensive summary of the evidence assessing the benefits and harms of intermittent iron supplementation in pregnant women on haematological and pregnancy outcomes. Findings suggest that intermittent regimens produced similar maternal and infant outcomes as daily supplementation but were associated with fewer side effects and reduced the risk of high levels of Hb in mid and late pregnancy, although the risk of mild anaemia near term was increased. While the quality of the evidence was assessed as low or very low, intermittent may be a feasible alternative to daily iron supplementation among those pregnant women who are not anaemic and have adequate antenatal care.

Daily oral iron supplementation during pregnancy

BACKGROUND

Iron and folic acid supplementation has been the preferred intervention to improve iron stores and prevent anaemia among pregnant women, and it is thought to improve other maternal and birth outcomes.

OBJECTIVES

To assess the effects of daily oral iron supplements for pregnant women, either alone or in conjunction with folic acid, or with other vitamins and minerals as a public health intervention in antenatal care.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (10 January 2015). We also searched the WHO International Clinical Trials Registry Platform (ICTRP) (26 February 2015) and contacted relevant organisations for the identification of ongoing and unpublished studies (26 February 2015) .

SELECTION CRITERIA

Randomised or quasi-randomised trials evaluating the effects of oral preventive supplementation with daily iron, iron + folic acid or iron + other vitamins and minerals during pregnancy.

DATA COLLECTION AND ANALYSIS

We assessed the methodological quality of trials using standard Cochrane criteria. Two review authors independently assessed trial eligibility, extracted data and conducted checks for accuracy. We used the GRADE approach to assess the quality of the evidence for primary outcomes.We anticipated high heterogeneity among trials and we pooled trial results using a random-effects model and were cautious in our interpretation of the pooled results: the random-effects model gives the average treatment effect.

MAIN RESULTS

We included 61 trials. Forty-four trials, involving 43,274 women, contributed data and compared the effects of daily oral supplements containing iron versus no iron or placebo.Preventive iron supplementation reduced maternal anaemia at term by 70% (risk ratio (RR) 0.30; 95% confidence interval (CI) 0.19 to 0.46, 14 trials, 2199 women, low quality evidence), iron-deficiency anaemia at term (RR 0.33; 95% CI 0.16 to 0.69, six trials, 1088 women), and iron deficiency at term by 57% (RR 0.43; 95% CI 0.27 to 0.66, seven trials, 1256 women, low quality evidence). There were no clear differences between groups for severe anaemia in the second or third trimester, or maternal infection during pregnancy (RR 0.22; 95% CI 0.01 to 3.20, nine trials, 2125 women, very low quality evidence; and, RR 1.21; 95% CI 0.33 to 4.46; one trial, 727 women, low quality evidence, respectively), or maternal mortality (RR 0.33; 95% CI 0.01 to 8.19, two trials, 12,560 women, very low quality evidence), or reporting of side effects (RR 1.29; 95% CI 0.83 to 2.02, 11 trials, 2423 women, very low quality evidence). Women receiving iron were on average more likely to have higher haemoglobin (Hb) concentrations at term and in the postpartum period, but were at increased risk of Hb concentrations greater than 130 g/L during pregnancy, and at term.Compared with controls, women taking iron supplements less frequently had low birthweight newborns (8.4% versus 10.3%, average RR 0.84; 95% CI 0.69 to 1.03, 11 trials, 17,613 women, low quality evidence), and preterm babies (RR 0.93; 95% CI 0.84 to 1.03, 13 trials, 19,286 women, moderate quality evidence). They appeared to also deliver slightly heavier babies (mean difference (MD) 23.75; 95% CI -3.02 to 50.51, 15 trials, 18,590 women, moderate quality evidence). None of these results were statistically significant. There were no clear differences between groups for neonatal death (RR 0.91; 95% CI 0.71 to 1.18, four trials, 16,603 infants, low quality evidence), or congenital anomalies (RR 0.88, 95% CI 0.58 to 1.33, four trials, 14,636 infants, low quality evidence).Twenty-three studies were conducted in countries that in 2011 had some malaria risk in parts of the country. In some of these countries/territories, malaria is present only in certain areas or up to a particular altitude. Only two of these studies reported malaria outcomes. There is no evidence that iron supplementation increases placental malaria. For some outcomes heterogeneity was higher than 50%.

AUTHORS' CONCLUSIONS

Supplementation reduces the risk of maternal anaemia and iron deficiency in pregnancy but the positive effect on other maternal and infant outcomes is less clear. Implementation of iron supplementation recommendations may produce heterogeneous results depending on the populations' background risk for low birthweight and anaemia, as well as the level of adherence to the intervention.

Daily oral iron supplementation during pregnancy

BACKGROUND

Iron and folic acid supplementation has been the preferred intervention to improve iron stores and prevent anaemia among pregnant women, and it may also improve other maternal and birth outcomes.

OBJECTIVES

To assess the effects of daily oral iron supplements for pregnant women, either alone or in conjunction with folic acid, or with other vitamins and minerals as a public health intervention.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (2 July 2012). We also searched the WHO International Clinical Trials Registry Platform (ICTRP) (2 July 2012) and contacted relevant organisations for the identification of ongoing and unpublished studies.

SELECTION CRITERIA

Randomised or quasi-randomised trials evaluating the effects of oral preventive supplementation with daily iron, iron + folic acid or iron + other vitamins and minerals during pregnancy.

DATA COLLECTION AND ANALYSIS

We assessed the methodological quality of trials using standard Cochrane criteria. Two review authors independently assessed trial eligibility, extracted data and conducted checks for accuracy.

MAIN RESULTS

We included 60 trials. Forty-three trials, involving more than 27,402 women, contributed data and compared the effects of daily oral supplements containing iron versus no iron or placebo.Overall, women taking iron supplements were less likely to have low birthweight newborns (below 2500 g) compared with controls (8.4% versus 10.2%, average risk ratio (RR) 0.81; 95% confidence interval (CI) 0.68 to 0.97, 11 trials, 8480 women) and mean birthweight was 30.81 g greater for those infants whose mothers received iron during pregnancy (average mean difference (MD) 30.81; 95% CI 5.94 to 55.68, 14 trials, 9385 women). Preventive iron supplementation reduced the risk of maternal anaemia at term by 70% (RR 0.30; 95% CI 0.19 to 0.46, 14 trials, 2199 women) and iron deficiency at term by 57% (RR 0.43; 95% CI 0.27 to 0.66, seven trials, 1256 women). Although the difference between groups did not reach statistical significance, women who received iron supplements were more likely than controls to report side effects (25.3% versus 9.91%) (RR 2.36; 95% CI 0.96 to 5.82, 11 trials, 4418 women), particularly at doses 60 mg of elemental iron or higher. Women receiving iron were on average more likely to have higher haemoglobin (Hb) concentrations at term and in the postpartum period, but were at increased risk of Hb concentrations greater than 130g/L during pregnancy and at term. Twenty-three studies were conducted in countries that in 2011 had some malaria risk in parts of the country. In some of these countries/territories, malaria is present only in certain areas or up to a particular altitude. Only two of these reported malaria outcomes. There is no evidence that iron supplementation increases placental malaria. For some outcomes heterogeneity was higher than 50%.

AUTHORS' CONCLUSIONS

Prenatal supplementation with daily iron are effective to reduce the risk of low birthweight, and to prevent maternal anaemia and iron deficiency in pregnancy. Associated maternal side effects and particularly high Hb concentrations during pregnancy at currently used doses suggest the need to update recommendations on doses and regimens for routine iron supplementation.

Intermittent oral iron supplementation during pregnancy

BACKGROUND

Anaemia is a frequent condition during pregnancy, particularly among women from developing countries who have insufficient iron intake to meet increased iron needs of both the mother and the fetus.Traditionally, gestational anaemia has been prevented with the provision of daily iron supplements throughout pregnancy, but adherence to this regimen due to side effects, interrupted supply of the supplements, and concerns about safety among women with an adequate iron intake, have limited the use of this intervention. Intermittent (i.e. one, two or three times a week on non-consecutive days) supplementation with iron alone or in combination with folic acid or other vitamins and minerals has recently been proposed as an alternative to daily supplementation.

OBJECTIVES

To assess the benefits and harms of intermittent supplementation with iron alone or in combination with folic acid or other vitamins and minerals to pregnant women on neonatal and pregnancy outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (23 March 2012). We also searched the WHO International Clinical Trials Registry Platform (ICTRP) for ongoing studies and contacted relevant organisations for the identification of ongoing and unpublished studies (23 March 2012).

SELECTION CRITERIA

Randomised or quasi-randomised trials.

DATA COLLECTION AND ANALYSIS

We assessed the methodological quality of trials using standard Cochrane criteria. Two review authors independently assessed trial eligibility, extracted data and conducted checks for accuracy.

MAIN RESULTS

This review includes 21 trials from 13 different countries, but only 18 trials (with 4072 women) reported on our outcomes of interest and contributed data to the review. All of these studies compared daily versus intermittent iron supplementation.Three studies provided iron alone, 12 iron+folic acid and three more iron plus multiple vitamins and minerals. Their methodological quality was mixed and most had high levels of attrition. Overall, there was no clear evidence of differences between groups for infant primary outcomes: low birthweight (average risk ratio (RR) 0.96; 95% confidence interval (CI) 0.61 to 1.52, seven studies), infant birthweight (mean difference MD -8.62 g; 95% CI -52.76 g to 35.52 g, eight studies), premature birth (average RR 1.82; 95% CI 0.75 to 4.40, four studies). None of the studies reported neonatal deaths or congenital anomalies.For maternal outcomes, there was no clear evidence of differences between groups for anaemia at term (average RR 1.22; 95% CI 0.84 to 1.80, four studies) and women receiving intermittent supplementation had less side effects (average RR 0.56; 95% CI 0.37 to 0.84, 11 studies) than those receiving daily supplements. Women receiving intermittent supplements were also at lower risk of having high haemoglobin (Hb) concentrations (greater than 130 g/L) during the second or third trimester of pregnancy (average RR 0.48; 95% CI 0.35 to 0.67, 13 studies). There were no significant differences in iron-deficiency anaemia between women receiving intermittent or daily iron+folic acid supplementation (average RR 0.71; 95% CI 0.08 to 6.63, 1 study). There were no maternal deaths (six studies) or women with severe anaemia in pregnancy (six studies). None of the studies reported on iron deficiency at term or infections during pregnancy.Where sufficient data were available for primary outcomes, we set up subgroups to look for possible differences between studies in terms of earlier or later supplementation; women's anaemia status at the start of supplementation; higher and lower weekly doses of iron; and the malarial status of the region in which the trials were conducted. There was no clear effect of these variables on the results of the review.

AUTHORS' CONCLUSIONS

The present systematic review is the most comprehensive summary of the evidence assessing the benefits and harms of intermittent iron supplementation regimens in pregnant women on haematological and pregnancy outcomes. The findings suggest that intermittent iron+folic acid regimens produce similar maternal and infant outcomes at birth as daily supplementation but are associated with fewer side effects. Women receiving daily supplements had increased risk of developing high levels of Hb in mid and late pregnancy but were less likely to present mild anaemia near term. Although the evidence is limited and the quality of the trials was low or very low, intermittent may be a feasible alternative to daily iron supplementation among those pregnant women who are not anaemic and have adequate antenatal care.

Iron deficiency in pregnancy

Iron deficiency (ID) and related anaemia (IDA) during pregnancy are highly prevalent worldwide in both developed and developing nations although the causes are often different. At conception, many women lack sufficient iron stores to meet the increased requirements of pregnancy, which are calculated at approximately 1200 mg. Appraisal of iron status in pregnant women is problematic, however the most reliable available diagnostic test is a serum ferritin < 20 µg/L. ID is often associated with other nutritional disorders, and there is frequently a secondary cause or association. A greater oral intake is usually insufficient to meet the increased demands of pregnancy, however regular oral supplements (given either daily or intermittently) can often meet maternal needs and avoid associated neonatal complications of IDA. Over-treatment with iron should be avoided, but intravenous administration is useful when deficiency is discovered late, is severe, or if the woman is intolerant of oral formulations. This paper reviews the current literature, and addresses differences in the prevalence and causes of ID betwen developed and developing nations. It examines gestational iron requirements, distinguishes between ID and IDA, and highlights difficulties in diagnostic testing. Finally, it appraises the evidence for and against different treatment regimens, ranging from food fortification to intravenous iron infusions, according to availability and to need.

Effects and safety of preventive oral iron or iron+folic acid supplementation for women during pregnancy

BACKGROUND

Intake of supplements containing iron or a combination of iron and folic acid by pregnant women may improve maternal health and pregnancy outcomes. Recently, intermittent supplementation regimens have been proposed as alternatives to daily regimens.

OBJECTIVES

To assess the effectiveness and safety of daily and intermittent use of iron or iron+folic acid supplements by pregnant women.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (March 2009) and contacted relevant organisations for the identification of ongoing and unpublished studies.

SELECTION CRITERIA

All randomised or quasi-randomised trials evaluating the effect of supplementation with iron or iron+folic acid during pregnancy.

DATA COLLECTION AND ANALYSIS

We assessed the methodological quality of trials using the standard Cochrane criteria. Two authors independently assessed which trials to include in the review and one author extracted data.

MAIN RESULTS

We included 49 trials, involving 23,200 pregnant women. Overall, the results showed significant heterogeneity across most prespecified outcomes and were analysed assuming random-effects. The trials provided limited information related to clinical maternal and infant outcomes.Overall, daily iron supplementation was associated with increased haemoglobin levels in maternal blood both before and after birth and reduced risk of anaemia at term. These effects did not differ significantly between women receiving intermittent or daily iron or iron+folic acid supplementation. Women who received daily prenatal iron supplementation with or without folic acid were less likely to have iron deficiency at term as defined by current cut-off values than those who received no treatment or placebo. Side effects and haemoconcentration (a haemoglobin level greater than 130 g/L) were more common among women who received daily iron or iron+folic acid supplementation than among those who received no treatment or placebo. The risk of haemoconcentration during the second and third trimester was higher among those on a daily regimen of iron supplementation. The clinical significance of haemoconcentration remains uncertain.

AUTHORS' CONCLUSIONS

Universal prenatal supplementation with iron or iron+folic acid provided either daily or weekly is effective to prevent anaemia and iron deficiency at term. We found no evidence, however, of the significant reduction in substantive maternal and neonatal adverse clinical outcomes (low birthweight, delayed development, preterm birth, infection, postpartum haemorrhage). Associated side effects and particularly haemoconcentration during pregnancy may suggest the need for revising iron doses and schemes of supplementation during pregnancy and adjust preventive iron supplementation recommendations.

Effects of routine oral iron supplementation with or without folic acid for women during pregnancy

BACKGROUND

It has been suggested that routine intake of supplements containing iron or combination of iron and folic acid during pregnancy improves maternal health and pregnancy outcomes.

OBJECTIVES

To assess the efficacy, effectiveness and safety of routine antenatal daily or intermittent iron supplementation with or without folic acid during pregnancy on the health of mothers and newborns.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (June 2005). Additionally, we contacted relevant organizations for the identification of ongoing and unpublished studies.

SELECTION CRITERIA

All randomised or quasi-randomised trials evaluating the effect of routine supplementation with iron or combination of iron and folic acid during pregnancy.

DATA COLLECTION AND ANALYSIS

We assessed trials for methodological quality using the standard Cochrane criteria. Two authors independently assessed the trials for inclusion and one author extracted data. We collected information on randomisation method, allocation concealment, blinding and loss to follow up. The primary outcomes included maternal and infant clinical and laboratory outcomes.

MAIN RESULTS

Forty trials, involving 12706 women, were included in the review. Overall, the results showed significant heterogeneity across most prespecified outcomes. Heterogeneity could not be explained by standard sensitivity analyses including quality assessment; therefore, all results were analysed assuming random-effects. Very limited information related to clinical maternal and infant outcomes was available in the included trials. The data suggest that daily antenatal iron supplementation increases haemoglobin levels in maternal blood both antenatally and postnatally. It is difficult to quantify this increase due to significant heterogeneity between the studies. Women who receive daily antenatal iron supplementation are less likely to have iron deficiency and iron-deficiency anaemia at term as defined by current cut-off values. Side-effects and haemoconcentration are more common in women who receive daily iron supplementation. No differences were evident between daily and weekly supplementation with regards to gestational anaemia; haemoconcentration during pregnancy appears less frequent with the weekly regimen. The clinical significance of hemoconcentration defined as haemoglobin greater than 130 g/L remains uncertain.

AUTHORS' CONCLUSIONS

Further studies are needed to assess the effects of routine antenatal supplementation with iron or a combination of iron and folic acid on clinically important maternal and infant outcomes.

Iron deficiency in pregnancy, obstetrics, and gynecology

Iron deficiency remains a major health risk in the United States, despite the apparent availability of a high-quality diet. In the United States, at least 7.8 million adolescent girls and premenopausal women are iron-deficient. Worldwide, the challenge of identifying and treating iron deficiency is enormous. Physicians involved in the primary care and in the obstetric and gynecologic care of women of all ages must be aware of the nature of the problem and the correct approach to screening, diagnosis, and treatment. The potential benefit to newborns and infants and to their mothers is substantial. Furthermore, a thorough diagnostic evaluation has considerable potential for uncovering a potentially lethal disease, such as gastrointestinal malignancy, in a curable phase.