Figure 1

Urinary iodine concentrations during pregnancy and 6 months postpartum according to the use of iodine-containing multivitamins, measured at 12 weeks (no iodine-containing multivitamins n = 89, iodine-containing multivitamins n = 76), 18 weeks (no iodine-containing multivitamins n = 81, iodine-containing multivitamins n = 79), 30 weeks (no iodine-containing multivitamins n = 58, iodine-containing multivitamins n = 62) 36 weeks (no iodine-containing multivitamins n = 51, iodine-containing multivitamins n = 60) and at 6 months post-partum (no iodine-containing multivitamins n = 21, iodine-containing multivitamins n = 17). Line and boxes represent the median and the inter-quartile range and whiskers represent the 95% confidence interval. *p < 0.05 between iodine supplement and no supplement group at 36 weeks (Mann Whitney U test); significant differences across gestation are represented by different alpha symbols (p < 0.01).