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Iron supplement in pregnancy and development of gestational diabetes—a randomised placebo‐controlled trial
Author(s) -
Chan KKL,
Chan BCP,
Lam KF,
Tam S,
Lao TT
Publication year - 2009
Publication title -
bjog: an international journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.157
H-Index - 164
eISSN - 1471-0528
pISSN - 1470-0328
DOI - 10.1111/j.1471-0528.2008.02014.x
Subject(s) - gestational diabetes , medicine , placebo , pregnancy , obstetrics , diabetes mellitus , iron supplementation , iron supplement , gestation , iron deficiency , endocrinology , alternative medicine , anemia , biology , pathology , genetics
Objective To test the hypothesis that iron supplement from early pregnancy would increase the risk of gestational diabetes mellitus (GDM). Design Randomised placebo‐controlled trial. Setting A university teaching hospital in Hong Kong. Population One thousand one hundred sixty‐four women with singleton pregnancy at less than 16 weeks of gestation with haemoglobin (Hb) level between 8 and 14 g/dl and no pre‐existing diabetes or haemoglobinopathies. Methods Women were randomly allocated to receive 60 mg of iron supplement daily ( n = 565) or placebo ( n = 599). Oral glucose tolerance tests (OGTTs) were performed at 28 and 36 weeks. Women were followed up until delivery. Outcome measures The primary outcome was development of GDM at 28 weeks. The secondary outcomes were 2‐hour post‐OGTT glucose levels, development of GDM at 36 weeks and delivery and infant outcomes. Results There was no significant difference in the incidence of GDM in the iron supplement and placebo groups at 28 weeks (OR: 1.04, 95% confidence interval [CI]: 0.7–1.53 at 90% power) or 36 weeks. Maternal Hb and ferritin levels were higher in the iron supplement group at delivery ( P < 0.001 and P = 0.003, respectively). Elective caesarean section rate was lower in the iron supplement group (OR: 0.58, 95% CI: 0.37–0.89). Infant birthweight was heavier ( P = 0.001), and there were fewer small‐for‐gestational‐age babies in the iron supplement group (OR: 0.46, 95% CI: 0.24–0.85). Conclusion Iron supplement from early pregnancy does not increase the risk of GDM. It may have benefits in terms of pregnancy outcomes.