A study that was conducted to assess the use, side effects and discontinuation rates of different iron preparations during pregnancy showed that ferrous bisglycinate therapy is accompanied by least side-effects and has a better compliance. In this study, 453 postpartum women were asked to complete a questionnaire on iron supplement use during their second and third trimesters. It was observed that nearly 45% of the participants reported at least 1 adverse effect, especially constipation (27.4%) and nausea (10.8%). Side effects were least with the use of ferrous bisglycinate and multivitamin preparations (21.2% and 23.7%, respectively), and highest with ferrous fumarate and immediate-release ferrous sulfate (56.3% and 53.7%, respectively). Moreover, discontinuation rates were also lowest for ferrous bisglycinate and multivitamin (9.1% and 10.5%, respectively).