Antenatal iron supplements consumed daily produce oxidative stress in contrast to weekly supplementation in Mexican non-anemic women

Universal prenatal daily supplementation with iron (60–120 mg iron) plus folic acid (0.4 mg), as recommended by INACG/WHO/UNICEF, prevents anemia where iron deficiency is prevalent but may be excessive for non-anemic women. Weekly supplementation with 120 mg iron plus various amounts of folic acid similarly prevents significant anemia.ObjectiveDetermine, in non-anemic pregnant women, if oxidative stress is produced by recommended daily or weekly supplementation schemes.Procedure100 non-anemic pregnant women, 30% iron-deficient at week 20, were randomly supplemented daily followed by weekly, each for 8 weeks, or in reversed order.ResultsWith daily supplementation thio-barbituric-acid-reacting-substances (TBARS) increased significantly and high serum ferritin, iron, and excessively elevated hemoglobin occurred near term. During weekly supplementation significant anemia and high iron parameters were prevented, and elevated TBARS declined.ConclusionIn non-anemic pregnant women both schemes prevented significant anemia. Oxidative stress occurred only during daily supplementation periods. Weekly supplementation appears safer.

► Weekly prenatal iron–folic acid–B12 safely prevents significant gestational anemia. ► Recommended daily 60 mg iron doses for non-anemic pregnant women may be excessive. ► Recommended prenatal daily iron doses produce oxidative stress shown by high TBARS. ► Weekly prenatal iron supplements after daily supplementation reduce TBARS levels. ► High serum iron levels in late pregnancy correlate with high TBARS serum levels.