The effectiveness of discontinuing iron-containing prenatal multivitamins on reducing the severity of nausea and vomiting of pregnancy.
J Obstet Gynaecol. 2009 Jan;29(1):13-6. PMID: 19280488
Nausea and vomiting of pregnancy (NVP) is experienced by the majority of pregnant women, and can negatively affect a women's quality of life. It has been suggested in observational studies that iron-containing prenatal multivitamins may increase the severity of NVP. The objective of this study was to determine whether decreasing iron exposure can mitigate NVP symptoms. Data were collected from a prospective cohort at the Motherisk Program in Toronto. Women (n = 97) seeking advice on managing severe NVP were advised to discontinue prenatal multivitamin administration and switch to folic acid, an adult multivitamin or a children's chewable multivitamin. Two-thirds (63 out of 97) (p < 0.001) of those women qualitatively reported an improvement in NVP symptoms after discontinuation of iron-containing prenatal multivitamins. These findings were verified quantitatively using both the pregnancy-unique quantification of emesis and nausea (PUQE) (p < 0.001) and well-being (p < 0.001) scoring systems. This is the first interventional study showing that discontinuation of iron results in improvement of NVP symptoms. Our data suggest that avoiding iron-containing prenatal multivitamins in the first trimester is effective in improving NVP symptoms in the majority of pregnant women suffering from morning sickness.