Iron supplementation in pregnancy—does the preparation matter?

Abstract

To assess the use, side effects and discontinuation rates of iron preparations during pregnancy. Six hundred and twelve randomly selected postpartum women completed a questionnaire on iron supplement use in the second and third trimesters. Of the 517 women (84.5%) reported using iron supplements, 453 were eligible for the study. The most common preparation was ferrous fumarate (46.8%, P < 0.01), followed by ferrous sulfate (31.8%), ferric polymaltose (12.4%), and ferric bisglycinate (7.3%). Almost half the participants (45%) reported at least one adverse effect, especially constipation (27.4%, P < 0.01), nausea (10.8%). Multivitamin preparations and ferric bisglycinate were associated with the fewest side effects (23.7, 21.2% respectively, P < 0.01), and ferrous fumarate and immediate-release ferrous sulfate with the most (56.3, 53.7% respectively). Eighty-three women discontinued their originally prescribed iron preparation, mainly (89%) due to side effects. Discontinuation rates were lowest for the multivitamin and ferric bisglycinate (10.5, 9.1%, respectively). In most cases, the specific preparation was recommended by the women's physician (76%). Ferrous fumarate-containing multivitamin preparations and ferric bisglycinate, although infrequently recommended as the first-line of iron supplementation, may be associated with less side effects and better compliance.