TY - JOUR

T1 - Iron supplements in pregnant women with normal iron status

T2 - A systematic review and meta-analysis

AU - Hansen, Rebecka

AU - Sejer, Emilie P.F.

AU - Holm, Charlotte

AU - Schroll, Jeppe B.

N1 - Funding Information: The authors kindly thank trialists who upon request provided us additional study information, and the Copenhagen University Library for valuable input to the search strategy development. Publisher Copyright: © 2023 The Authors. Acta Obstetricia et Gynecologica Scandinavica published by John Wiley & Sons Ltd on behalf of Nordic Federation of Societies of Obstetrics and Gynecology (NFOG).

PY - 2023

Y1 - 2023

N2 - Introduction: Effects of daily iron supplementation in iron replete pregnancy are unclear. This systematic review aimed to assess benefits and harms of oral iron supplements in pregnant women without anemia and iron deficiency. Material and methods: We predefined and registered a protocol in PROSPERO (CRD42020186210) and performed the review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology. We searched for randomized clinical trials (RCTs) and observational studies comparing daily oral iron supplementation with no iron supplements in non-anemic iron replete pregnant women. Searches were conducted in MEDLINE (by PubMed), EMBASE (by OVID), Cochrane Library, and ClinicalTrials.gov from inception to September 2022 without language restrictions. Two authors independently screened records, extracted data, and assessed risk of bias using the revised Cochrane risk of bias tool (RoB2). One author read full-texts, assessed certainty of evidence by GRADE and conducted meta-analyses using a random-effects model. Primary outcomes included iron deficiency anemia, iron deficiency, hemoglobin >130 g/L, elevated iron status, small for gestational age newborns, low birthweight newborns, preterm birth, and congenital anomalies. Results: Eight RCTs (2822 women) but no observational studies were eligible for inclusion. Daily oral iron supplementation in pregnancy probably reduces iron deficiency anemia at term (risk ratio [RR]: 0.51, 95% confidence interval [CI]: 0.38–0.70; 4 RCTs, 1670 women; I2 = 13%; moderate-certainty evidence) and the incidence of low birthweight babies (RR: 0.30, 95% CI: 0.13–0.68; 2 RCTs, 361 infants; I2 = 0%; moderate-certainty evidence). In addition, it may reduce iron deficiency at term (RR: 0.74, 95% CI: 0.60–0.92; 4 RCTs, 1663 women; I2 = 58%; low-certainty evidence) and the incidence of small for gestational age babies (RR: 0.39, 95% CI: 0.17–0.86; 1 RCT, 213 infants; I2 not estimable; low-certainty evidence). Conclusions: Daily iron supplementation in iron replete non-anemic pregnant women probably reduces the risk of maternal iron deficiency anemia at term and low birthweight.

AB - Introduction: Effects of daily iron supplementation in iron replete pregnancy are unclear. This systematic review aimed to assess benefits and harms of oral iron supplements in pregnant women without anemia and iron deficiency. Material and methods: We predefined and registered a protocol in PROSPERO (CRD42020186210) and performed the review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology. We searched for randomized clinical trials (RCTs) and observational studies comparing daily oral iron supplementation with no iron supplements in non-anemic iron replete pregnant women. Searches were conducted in MEDLINE (by PubMed), EMBASE (by OVID), Cochrane Library, and ClinicalTrials.gov from inception to September 2022 without language restrictions. Two authors independently screened records, extracted data, and assessed risk of bias using the revised Cochrane risk of bias tool (RoB2). One author read full-texts, assessed certainty of evidence by GRADE and conducted meta-analyses using a random-effects model. Primary outcomes included iron deficiency anemia, iron deficiency, hemoglobin >130 g/L, elevated iron status, small for gestational age newborns, low birthweight newborns, preterm birth, and congenital anomalies. Results: Eight RCTs (2822 women) but no observational studies were eligible for inclusion. Daily oral iron supplementation in pregnancy probably reduces iron deficiency anemia at term (risk ratio [RR]: 0.51, 95% confidence interval [CI]: 0.38–0.70; 4 RCTs, 1670 women; I2 = 13%; moderate-certainty evidence) and the incidence of low birthweight babies (RR: 0.30, 95% CI: 0.13–0.68; 2 RCTs, 361 infants; I2 = 0%; moderate-certainty evidence). In addition, it may reduce iron deficiency at term (RR: 0.74, 95% CI: 0.60–0.92; 4 RCTs, 1663 women; I2 = 58%; low-certainty evidence) and the incidence of small for gestational age babies (RR: 0.39, 95% CI: 0.17–0.86; 1 RCT, 213 infants; I2 not estimable; low-certainty evidence). Conclusions: Daily iron supplementation in iron replete non-anemic pregnant women probably reduces the risk of maternal iron deficiency anemia at term and low birthweight.

KW - iron

KW - iron deficiency

KW - iron replete

KW - maternal iron deficiency

KW - non-anemic

KW - pregnant

KW - review

U2 - 10.1111/aogs.14607

DO - 10.1111/aogs.14607

M3 - Review

C2 - 37403900

AN - SCOPUS:85164476218

VL - 102

SP - 1147

EP - 1158

JO - Acta Obstetricia et Gynecologica Scandinavica

JF - Acta Obstetricia et Gynecologica Scandinavica

SN - 0001-6349

IS - 9

ER -